1,036 results on '"Horizontal resolution"'
Search Results
2. Effect of Horizontal Resolution on a Meso‐β‐Scale Vortex Simulation in an Extreme Rainstorm on 22 May 2020 Over South China: A Contrastive Study Based on Different‐Resolution Ensembles.
- Author
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Zhang, Guanshun, Zhang, Xubin, and Yang, Zhaoli
- Subjects
- *
RAINSTORMS , *GRAVITY waves , *PHOTOVOLTAIC power systems , *PROCESS heating , *ADVECTION-diffusion equations - Abstract
A transient extreme rainstorm that occurred over Guangzhou city, China, on 22 May 2020, has been investigated based on two ensemble prediction systems (EPSs), one with 9‐km (TRAMS9km‐EPS) and the other with 3‐km (TRAMS3km‐EPS) grid spacings, respectively. The results show that the better performance in the rainstorm event of TRAMS3km‐EPS than that of TRAMS9km‐EPS has been attributed to the reasonable simulation of an eastward propagating meso‐β‐scale convective vortex (MβCV). The composite evolution of the good‐performing members for the two EPSs has verified the important role of the MβCV in modulating the structure of low‐level jet (LLJ) to converge toward the Guangzhou city, facilitating the formation of the rainstorm. In comparison to the gravity wave disturbance when LLJ passed through the mountains in TRAMS3km‐EPS, the topographic effect induced the moist air to ascend deeply in TRAMS9km‐EPS, which directly led to earlier outbreaks of convection and rainstorm processes and affected the structural intensity of the upstream MβCV. Quantitative PV diagnosis has demonstrated that the dispersedly strong high‐PV systems in TRAMS3km‐EPS were caused by positive feedback effect between meso‐scale convective systems and diabatic heating, and were favorable for the entire cyclonic development of MβCV. The unsymmetrical PV tendency around the moving MβCV under the combined effect of diabatic heating and advection process in TRAMS9km‐EPS resulted in a rapid propagation of this system. However, the symmetrically developed PV system within the MβCV in TRAMS3km‐EPS allowed the enhanced cyclonic circulation to persistently affect Guangzhou city, inducing extreme rainstorms similar to the observations. Plain Language Summary: An eastward propagating meso‐β‐scale convective vortex (MβCV) that triggered a transient extreme rainstorm over Guangzhou city, China, on 22 May 2020, has been examined and simulated using a same ensemble prediction system (EPS) model with two horizontal resolutions (3 and 9 km). In this study, we have analyzed the similarities and differences between the two EPSs. Our results show that the effect of horizontal resolution resulted in distinct MβCV structures in the two EPSs and led to different rainstorm processes in terms of intensity and duration. Some aspects, such as the low‐level jet, topographic effect, and small‐scale disturbances, are specifically compared between the two EPSs. The associated research highlights the effect of horizontal resolution on the MβCV simulation and a possible development mechanism of such a mesoscale system. Key Points: The topographic uplift and fore‐mountain convergence processes are amplified in low‐resolution ensemble simulationsThe unsymmetrical PV tendency around MβCV center determines the direction and velocity of the moving MβCVSmall‐scale convective systems enhance cyclonic structure of MβCV through positive feedback with diabatic heating [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Role of high-resolution modeling system in prediction of heavy rainfall events over Tamil Nadu and Kerala on different global/regional datasets
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Chanchal, Km and Singh, Kuvar Satya
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- 2024
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4. The impact of horizontal resolution on the representation of atmospheric circulation types in Western Europe using the MPI‐ESM model.
- Author
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Ibebuchi, Chibuike Chiedozie
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ATMOSPHERIC circulation , *DISTRIBUTION (Probability theory) , *SEA level , *NO-tillage - Abstract
In this study, the added value in using the sea level pressure field from the coupled higher‐resolution version of the Max Planck Institute Earth System Model (MPI‐ESM‐HR), compared to the lower‐resolution version (MPI‐ESM‐LR) for circulation typing, within the regional context of Western Europe was examined. The results show that the MPI‐ESM‐HR and the MPI‐ESM‐LR simulations can produce the classified circulation types (CTs) and their long‐term statistical characteristics as obtained from the ERA5 reanalysis. Overall, there are improvements in the composite maps, probability of occurrence and annual cycle of the simulated CTs in the MPI‐ESM‐HR compared to the MPI‐ESM‐LR. The model bias in simulating the structure of anticyclonic circulations over the Western European landmass was reduced by 14% under MPI‐ESM‐HR. Furthermore, under the shared socio‐economic pathways (SSP2‐4.5 and SSP5‐8.5) future emission scenarios, the historical CTs in the region of assessment were classified, suggesting that in Western Europe, the same historical CTs are present under future climate change scenarios. However, the frequency distribution and geographical structure of some of the CTs in Western Europe are projected to change by the MPI‐ESM model, especially under the higher future emission scenario. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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5. Effect of Horizontal Resolution on a Meso‐β‐Scale Vortex Simulation in an Extreme Rainstorm on 22 May 2020 Over South China: A Contrastive Study Based on Different‐Resolution Ensembles
- Author
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Guanshun Zhang, Xubin Zhang, and Zhaoli Yang
- Subjects
extreme rainstorm ,ensemble prediction system ,horizontal resolution ,meso‐β‐scale convective vortex ,potential vorticity ,Astronomy ,QB1-991 ,Geology ,QE1-996.5 - Abstract
Abstract A transient extreme rainstorm that occurred over Guangzhou city, China, on 22 May 2020, has been investigated based on two ensemble prediction systems (EPSs), one with 9‐km (TRAMS9km‐EPS) and the other with 3‐km (TRAMS3km‐EPS) grid spacings, respectively. The results show that the better performance in the rainstorm event of TRAMS3km‐EPS than that of TRAMS9km‐EPS has been attributed to the reasonable simulation of an eastward propagating meso‐β‐scale convective vortex (MβCV). The composite evolution of the good‐performing members for the two EPSs has verified the important role of the MβCV in modulating the structure of low‐level jet (LLJ) to converge toward the Guangzhou city, facilitating the formation of the rainstorm. In comparison to the gravity wave disturbance when LLJ passed through the mountains in TRAMS3km‐EPS, the topographic effect induced the moist air to ascend deeply in TRAMS9km‐EPS, which directly led to earlier outbreaks of convection and rainstorm processes and affected the structural intensity of the upstream MβCV. Quantitative PV diagnosis has demonstrated that the dispersedly strong high‐PV systems in TRAMS3km‐EPS were caused by positive feedback effect between meso‐scale convective systems and diabatic heating, and were favorable for the entire cyclonic development of MβCV. The unsymmetrical PV tendency around the moving MβCV under the combined effect of diabatic heating and advection process in TRAMS9km‐EPS resulted in a rapid propagation of this system. However, the symmetrically developed PV system within the MβCV in TRAMS3km‐EPS allowed the enhanced cyclonic circulation to persistently affect Guangzhou city, inducing extreme rainstorms similar to the observations.
- Published
- 2024
- Full Text
- View/download PDF
6. Evaluation of the seasonal to decadal variability in dynamic sea level simulations from CMIP5 to CMIP6
- Author
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Chenyang Jin, Hailong Liu, and Pengfei Lin
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CMIP6 ,CMIP5 ,Dynamic sea level ,Root-mean-square error ,Pattern correlation coefficient ,Horizontal resolution ,Science ,Geology ,QE1-996.5 - Abstract
Abstract Previous studies have revealed little progress in the ensemble mean of Coupled Model Intercomparison Project Phase 6 (CMIP6) models compared to Phase 5 (CMIP5) models in simulating global dynamic sea level (DSL). This study investigates the performance of the CMIP5 and CMIP6 ensembles in simulating the spatial pattern and magnitude of DSL climatology, seasonal variability, interannual variability, and decadal variability by using the pattern correlation coefficient (PCC) and root-mean-square error (RMSE) as metrics. We show that the top models of the CMIP6 ensemble perform better than those of the CMIP5 ensemble in the simulation of DSL climatology and seasonal and interannual variability, but not DSL decadal variability. An intermodel linear relationship between the RMSE and PCC is found for both the CMIP5 and CMIP6 ensembles; however, this intermodel relationship is more linearly correlated in the CMIP6 ensemble and not significant for DSL decadal variability. The results show that the finer-horizontal resolution models tend to yield a smaller RMSE and a larger PCC in the DSL climatology, seasonal variability, interannual variability but not decadal variability simulations, and the relationship is more evident for the CMIP6 ensemble than for the CMIP5 ensemble.
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- 2023
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7. Sensitivity of the CALMET-CALPUFF model system on estimating PM10 concentrations at a mining site in northern Colombia
- Author
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Heli A. Arregocés and Roberto Rojano
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Horizontal resolution ,Atmospheric modeling ,Parameterization ,Sensitivity analysis ,Environmental engineering ,TA170-171 ,Chemical engineering ,TP155-156 - Abstract
Pollutant dispersion models are essential tools to assess the influence of emission sources in the atmosphere. We performed PM10 simulations using the CALMET-CALPUFF system at a mining site in northern. We set the dynamic parameters (TERRAD, RMAX1, RMAX2, R1, R2, and Calmet-Bias) and established different horizontal grid spacing (0.5 km, 1 km, 2 km, 3 km, and 5 km). Also, we adjusted the surface roughness length (0.1 m–0.5 m) values to determine the sensitivity of the dispersion model. Blocking effects due to terrain, represented by TERRAD, and horizontal resolution in the simulations significantly influence PM10 estimates. TERRAD values below 6 km reduced the values of MSE (0.75 μg/m3 - 4 μg/m3), BIAS (0.5 μg/m3–6 μg/m3), and FB (up to 0.32) at all receptors. The modeling's horizontal resolution of 0.5 km allowed us to identify high PM10 concentrations areas. However, it increases the MSE values (6.42 μg/m3–12.29 μg/m3) compared to the EPA-Federal-Land-Manager-recommended parameter configuration settings of the modeling system. Increasing surface roughness length values slightly increased the MSE values (
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- 2023
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8. Evaluation of the seasonal to decadal variability in dynamic sea level simulations from CMIP5 to CMIP6.
- Author
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Jin, Chenyang, Liu, Hailong, and Lin, Pengfei
- Subjects
SEASONS ,CLIMATOLOGY ,STATISTICAL correlation - Abstract
Previous studies have revealed little progress in the ensemble mean of Coupled Model Intercomparison Project Phase 6 (CMIP6) models compared to Phase 5 (CMIP5) models in simulating global dynamic sea level (DSL). This study investigates the performance of the CMIP5 and CMIP6 ensembles in simulating the spatial pattern and magnitude of DSL climatology, seasonal variability, interannual variability, and decadal variability by using the pattern correlation coefficient (PCC) and root-mean-square error (RMSE) as metrics. We show that the top models of the CMIP6 ensemble perform better than those of the CMIP5 ensemble in the simulation of DSL climatology and seasonal and interannual variability, but not DSL decadal variability. An intermodel linear relationship between the RMSE and PCC is found for both the CMIP5 and CMIP6 ensembles; however, this intermodel relationship is more linearly correlated in the CMIP6 ensemble and not significant for DSL decadal variability. The results show that the finer-horizontal resolution models tend to yield a smaller RMSE and a larger PCC in the DSL climatology, seasonal variability, interannual variability but not decadal variability simulations, and the relationship is more evident for the CMIP6 ensemble than for the CMIP5 ensemble. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
9. Added value of high-resolution regional climate model in simulating precipitation based on the changes in kinetic energy
- Author
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Gayoung Kim, Jineun Kim, and Dong-Hyun Cha
- Subjects
Regional climate model ,Added Value ,Horizontal resolution ,Kinetic energy ,Science ,Geology ,QE1-996.5 - Abstract
Abstract As the resolution of regional climate models has increased with the development of computing resources, Added Values (AVs) have always been a steady research topic. Most previous studies examined AVs qualitatively by comparing model results with different model resolutions qualitatively. This study tried to quantitatively investigate the AV of the high-resolution regional climate model for precipitation by analyzing the distribution of kinetic energy according to the different wavelengths at two different resolutions (36 km vs. 4 km), away from the traditional comparative analysis. In addition, the experiment that the low-resolution topography was forced to the high-resolution model was additionally conducted to separate the AVs associated with the topographic effect. Among the three experiments, two with the same topography and two with the exact horizontal resolution were compared separately. With identical topography, the high-resolution model simulated amplified precipitation intensity more than the low-resolution model in all quantiles, especially for extreme precipitation. The precipitation generated by mesoscale or smaller scale weather/climate events was also simulated with greater intensity in the high-resolution model. With the same grid spacing, the more detailed topography model showed AV for increasing spatial variability of precipitation, especially in mountainous regions. The AVs identified in this study were related to kinetic energy with wavelengths at the meso-beta or smaller scale. On the other hand, the kinetic energy above the meso-alpha or larger scale has no significant correlation with the AV of precipitation.
- Published
- 2022
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10. Effect of Horizontal Resolution of Printer on Trueness of 3D-Printed Provisional Crown: An In Vitro Study.
- Author
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Hai, Pham Nhu, Son, Tong Minh, Anh, Nguyen Viet, Ngoc, Vo Truong Nhu, and Tra, Nguyen Thu
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3-D printers ,COMPUTER-aided design ,MOLARS ,DENTAL laboratories ,MANDIBLE - Abstract
Objectives Provisional crowns play an integral role in prosthodontic therapy and need to be fabricated with high accuracy to ensure good marginal fit and proper contour. The aim of this study is to evaluate the effect of 3D printer's horizontal pixel resolution on trueness of the intaglio surface, external surface, and marginal area and the actual marginal adaptation of the interim crowns. Materials and Methods A gypsum reference model of mandible with a prepared right first molar was scanned with a dental laboratory scanner (AutoScan-DS-MIX, Shining 3D) and a digital provisional crown was design using the computer-aided design (CAD) software (Exocad). The provisional crown was manufactured by two printers with different horizontal resolutions (Sonic Mini 4K Printer and Sonic Mini 8K Printer). The printed crowns were scanned using the aforementioned scanner. The trueness of the external surface, internal surface, and marginal area of the provisional crowns was evaluated by comparing the scanned data with the reference CAD design data using a 3D inspection software (Geomagic Control X, 3D systems). The trueness of the crown manufactured by two printers was compared by a two-sided test (α = 0.05). Finally, the marginal adaptation of the provisional crowns was evaluated on the printed removable dies and compared. Results The results revealed that there was a significant difference in the trueness of the marginal area and the marginal adaptation (p < 0.05). Conclusions It can be concluded that the trueness of provisional crown marginal area and the marginal adaptation was affected by the horizontal resolution of the 3D printer. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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11. Added value of high-resolution regional climate model in simulating precipitation based on the changes in kinetic energy.
- Author
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Kim, Gayoung, Kim, Jineun, and Cha, Dong-Hyun
- Subjects
KINETIC energy ,ATMOSPHERIC models ,PRECIPITATION variability ,TOPOGRAPHY - Abstract
As the resolution of regional climate models has increased with the development of computing resources, Added Values (AVs) have always been a steady research topic. Most previous studies examined AVs qualitatively by comparing model results with different model resolutions qualitatively. This study tried to quantitatively investigate the AV of the high-resolution regional climate model for precipitation by analyzing the distribution of kinetic energy according to the different wavelengths at two different resolutions (36 km vs. 4 km), away from the traditional comparative analysis. In addition, the experiment that the low-resolution topography was forced to the high-resolution model was additionally conducted to separate the AVs associated with the topographic effect. Among the three experiments, two with the same topography and two with the exact horizontal resolution were compared separately. With identical topography, the high-resolution model simulated amplified precipitation intensity more than the low-resolution model in all quantiles, especially for extreme precipitation. The precipitation generated by mesoscale or smaller scale weather/climate events was also simulated with greater intensity in the high-resolution model. With the same grid spacing, the more detailed topography model showed AV for increasing spatial variability of precipitation, especially in mountainous regions. The AVs identified in this study were related to kinetic energy with wavelengths at the meso-beta or smaller scale. On the other hand, the kinetic energy above the meso-alpha or larger scale has no significant correlation with the AV of precipitation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Impact of Horizontal Resolution (Submesoscale Permitting vs. Mesoscale Resolving) on Ocean Dynamic Features in the South China Sea.
- Author
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Wu, Renhao, Jia, Liqun, Li, Chunyan, Liu, Yu, Han, Bo, and Chen, Dake
- Subjects
- *
OCEANOGRAPHY , *OCEAN , *OCEAN dynamics , *OCEAN circulation , *VERTICAL motion ,KUROSHIO - Abstract
Model resolution is a key factor that impacts the model bias in simulating ocean dynamics. How would model resolution influence model bias is an important question. In this study, we set up two sets of experiments with identical settings except the grid resolution, one with a minimum spacing of 2 km, referred to as the submesoscale permitting (SP) model, and the other with a minimum spacing of 6 km, referred to as the mesoscale resolving (MR) model, to investigate the impact of horizontal resolution on simulated dynamic features in the South China Sea. Results show that the SP outperforms the MR model in simulating both barotropic and baroclinic tides, upper ocean circulation, sea surface height, and temperature in the South China Sea, and in simulating the evolution of the eddy pair east of Indo‐China Peninsula in summer and the Kuroshio loop current in the Luzon Strait in winter. The SP model also performs better in simulating thermal structure within the ocean and the winter mixed layer depth. Additionally, the SP model can capture more vertical motion features. The superiority of the SP model lies in its ability to better resolve terrain features that have a significant impact on ocean dynamical processes, and to resolve more physical processes. As a result, the SP model relies less on the uncertain parameterized processes. Our study has important implications for studies on the modeling of physical oceanography in the South China Sea, as well as for the reduction of climate model biases. Plain Language Summary: The spatial resolution of numerical models significantly influences the model performance. The question is, how can model bias be reduced by increasing model resolution. By examining results from a numerical model with different spatial resolutions, involving some important ocean dynamical processes in the South China Sea, we addressed this question. This is done through two sets of numerical experiments with different horizontal resolutions but otherwise identical settings. Results show that the higher resolution model (∼2 km) outperforms the lower resolution model (∼6 km) in all dynamical and thermal features in the South China Sea. Analysis shows that this is mainly related to the fact that higher resolution models can better resolve the topography and more physical processes. Key Points: Two sets of models with different horizontal resolutions simulate key ocean dynamics processes in the South China SeaThe higher resolution model outperforms the lower resolution model in simulating all dynamical and thermal features of interestPreliminary analysis suggests that higher resolution models can better resolve topography as well as more physical processes [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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13. Decadal Methane Emission Trend Inferred from Proxy GOSAT XCH4 Retrievals: Impacts of Transport Model Spatial Resolution.
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Zhu, Sihong, Feng, Liang, Liu, Yi, Wang, Jing, and Yang, Dongxu
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SPATIAL resolution , *ATMOSPHERIC methane , *KALMAN filtering , *CHEMICAL models , *GREENHOUSE gases , *METHANE , *NATURAL gas vehicles - Abstract
In recent studies, proxy XCH4 retrievals from the Japanese Greenhouse gases Observing SATellite (GOSAT) have been used to constrain top-down estimation of CH4 emissions. Still, the resulting interannual variations often show significant discrepancies over some of the most important CH4 source regions, such as China and Tropical South America, by causes yet to be determined. This study compares monthly CH4 flux estimates from two parallel assimilations of GOSAT XCH4 retrievals from 2010 to 2019 based on the same Ensemble Kalman Filter (EnKF) framework but with the global chemistry transport model (GEOS-Chem v12.5) being run at two different spatial resolutions of 4° × 5° (R4, lon × lat) and 2° × 2.5° (R2, lon × lat) to investigate the effects of resolution-related model errors on the derived long-term global and regional CH4 emission trends. We found that the mean annual global methane emission for the 2010s is 573.04 Tg yr−1 for the inversion using the R4 model, which becomes about 4.4 Tg yr−1 less (568.63 Tg yr−1) when a finer R2 model is used, though both are well within the ensemble range of the 22 top-down results (2008–17) included in the current Global Carbon Project (from 550 Tg yr−1 to 594 Tg yr−1). Compared to the R2 model, the inversion based on the R4 tends to overestimate tropical emissions (by 13.3 Tg yr which is accompanied by a general underestimation (by 8.9 Tg yr−1) in the extratropics. Such a dipole reflects differences in tropical-mid-latitude air exchange in relation to the model's convective and advective schemes at different resolutions. The two inversions show a rather consistent long-term CH4 emission trend at the global scale and over most of the continents, suggesting that the observed rapid increase in atmospheric methane can largely be attributed to the emission growth from North Africa (1.79 Tg yr−2 for R4 and 1.29 Tg yr−2 for R2) and South America Temperate (1.08 Tg yr−2 for R4 and 1.21 Tg yr−2 for R2) during the first half of the 2010s, and from Eurasia Boreal (1.46 Tg yr−2 for R4 and 1.63 Tg yr−2 for R2) and Tropical South America (1.72 Tg yr−2 for R4 and 1.43 Tg yr−2 for R2) over 2015–19. In the meantime, emissions in Europe have shown a consistent decrease over the past decade. However, the growth rates by the two parallel inversions show significant discrepancies over Eurasia Temperate, South America Temperate, and South Africa, which are also the places where recent GOSAT inversions usually disagree with one other. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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14. Does Increasing Horizontal Resolution Improve Seasonal Prediction of Indian Summer Monsoon?: A Climate Forecast System Model Perspective.
- Author
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Kumar, Siddharth, Phani, R., Mukhopadhyay, P., and Balaji, C.
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SEASONS , *ATMOSPHERIC models , *MARKOV processes , *FORECASTING , *LANGUAGE policy - Abstract
The seasonal prediction skill of climate forecast system model with two different resolutions, namely T126 and T382, is studied using hindcast data. Using novel diagnostic tools such as total variation distance and two‐state Markov Chain analysis, it is shown that increasing the horizontal resolution of the model has minimal impact on the quality of seasonal prediction. The underlying rain distribution and associated transition probabilities are very similar in both model versions. The Markov chain analysis also provides critical clues about the issues associated with convective processes in the model. Both the models produce longer (shorter) wet (dry) spells compared to the observations. Models are trying to bring the atmosphere closer to convective quasi‐equilibrium, leading to a substantial departure from observed features. Although the conventional error metrics are helpful to assess the prediction skills, the new metrics used in the study provide further insights on possible pathways to improve model moist physics. Plain Language Summary: The state of the art in respect to the prediction of Indian summer monsoon uses coupled climate models. Models, in general, have a hard time producing an accurate forecast of seasonal mean monsoon. Serious effort is being put globally to improve the quality of the forecast. One of the simple and easy to comprehend approaches among the scientific community is to increase the model's horizontal resolution to improve the accuracy of the predictions. The present study indicates that this approach alone is not very useful as there is an only marginal improvement with an increase in the resolutions. Key Points: Novel metrics have been used to compare model hindcast at different horizontal resolutionsPrevious studies claiming an improved simulation of monsoon with higher resolutions climate forecast system model require further investigationOnly a marginal improvement is seen in the fidelity of the model with an increase in horizontal resolution [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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15. Dependence of dense filament frontogenesis in a hydrostatic model.
- Author
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Fan, Yalin, Yu, Zhitao, Sullivan, Peter, and Rydbeck, Adam
- Abstract
• Cold filament frontogenesis in a hydrostatic model - NCOM. • NCOM can predict the characteristics of frontogenesis but fails to capture the dynamics. • Horizontal mixing parameterization in NCOM has marginal effect on frontogenesis. • Higher model resolution is corresponding to stronger frontogenesis. • Parameterized wave effect in vertical mixing cannot represent the real physics of wave-front interaction. In this study, a hydrostatic model - the Navy Coastal Ocean Model (NCOM) is used to analyze the temporal evolution of a cold filament under moderate wind (along / cross filament) and surface cooling forcing conditions. The experimental framework adhered to the setup used in large eddy simulations by Sulllivan and McWilliams (2018). For each forcing scenario, the impact of horizontal resolutions is systematically explored through varies model resolutions of 100 m, 50 m, and 20 m; and the influence of horizontal mixing is investigated by adjusting the Smagorinsky constant within the Smagorinsky horizontal mixing scheme. The role of surface gravity waves is also assessed by conducting experiments both with and without surface wave forcing. The outcomes of our study revealed that while the hydrostatic model is able to predict the correct characteristics/physical appearance of filament frontogenesis, it fails to capture the precise dynamics of the phenomenon. Horizontal mixing parameterization in the model was found to have marginal effect on frontogenesis, and the frontal arrest is controlled by the model's subgrid-scale artificial regularization procedure instead of horizontal shear instability. Consequently, higher resolution is corresponding to stronger frontogenesis in the model. Thus, whether the hydrostatic model can produce realistic magnitude of frontogenesis is purely dependent on the characteristic of the front/filament simulated and model resolution. Moreover, examination of the parameterized effect of surface gravity wave forcing through vertical mixing unveiled a limited impact on frontogenesis, suggesting that the parameterization falls short in representing the real physics of wave-front interaction. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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16. Experimental validation of the horizontal resolution improvement by ultra-wideband metasurfaces for GPR systems.
- Author
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Zheng, Wuan, Hao, Tong, Li, Xiaojing, and Luo, Wenhao
- Subjects
- *
GROUND penetrating radar , *NONDESTRUCTIVE testing , *ELECTROMAGNETIC waves , *BURIED pipes (Engineering) , *MATERIALS testing - Abstract
Achieving high horizontal resolution is crucial for general non-destructive testing (NDT) applications, and in the domain of ground penetrating radar (GPR), it can be more challenging due to inefficient transmissions of electromagnetic waves into and through complex material under test (MUT). In this study, we showcase the validation results of our recently designed ultra-wideband metasurface (UWM) in improving the horizontal resolution for GPR B-Scan images. This UWM has an ultra-wide working frequency band (100%) from 1 to 3 GHz, in which high-frequency GPR signals can be enhanced and transmitted into MUT. Our fourteen-day consecutive GPR experiments demonstrate that two buried pipes with an edge-to-edge spacing of 8 cm that are hard to distinguish by traditional GPR surveys can be visually identified by depositing the UWM atop the MUT. The underlying mechanism is the sustained and improved transmission of high-frequency signals into the MUT, enabled by the removal of transmission coupling loss by the UWM at the air–MUT interface and the resulting enhanced transmission of more high-frequency components. Our simulations also provide quantitative analysis of such enhanced behavior with a nominal transmittance increase of 30% ∼ 50%. We believe the horizontal resolution improvement enabled by UWM will open a new corridor for high-resolution GPR system design. • An ultra-wideband metasurface (UWM) is designed for enhanced signal transmission in GPR surveys. • Multi-day GPR surveys validate the horizontal resolution improvement assisted by UWM. • Simulation results showcase the GPR transmittance increase of 30% ∼ 50%. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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17. Evaluating the Impact of Chemical Complexity and Horizontal Resolution on Tropospheric Ozone Over the Conterminous US With a Global Variable Resolution Chemistry Model
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Rebecca H. Schwantes, Forrest G. Lacey, Simone Tilmes, Louisa K. Emmons, Peter H. Lauritzen, Stacy Walters, Patrick Callaghan, Colin M. Zarzycki, Mary C. Barth, Duseong S. Jo, Julio T. Bacmeister, Richard B. Neale, Francis Vitt, Erik Kluzek, Behrooz Roozitalab, Samuel R. Hall, Kirk Ullmann, Carsten Warneke, Jeff Peischl, Ilana B. Pollack, Frank Flocke, Glenn M. Wolfe, Thomas F. Hanisco, Frank N. Keutsch, Jennifer Kaiser, Thao Paul V. Bui, Jose L. Jimenez, Pedro Campuzano‐Jost, Eric C. Apel, Rebecca S. Hornbrook, Alan J. Hills, Bin Yuan, and Armin Wisthaler
- Subjects
atmospheric chemistry ,tropospheric ozone ,air quality ,aircraft campaigns ,horizontal resolution ,chemical complexity ,Physical geography ,GB3-5030 ,Oceanography ,GC1-1581 - Abstract
Abstract A new configuration of the Community Earth System Model (CESM)/Community Atmosphere Model with full chemistry (CAM‐chem) supporting the capability of horizontal mesh refinement through the use of the spectral element (SE) dynamical core is developed and called CESM/CAM‐chem‐SE. Horizontal mesh refinement in CESM/CAM‐chem‐SE is unique and novel in that pollutants such as ozone are accurately represented at human exposure relevant scales while also directly including global feedbacks. CESM/CAM‐chem‐SE with mesh refinement down to ∼14 km over the conterminous US (CONUS) is the beginning of the Multi‐Scale Infrastructure for Chemistry and Aerosols (MUSICAv0). Here, MUSICAv0 is evaluated and used to better understand how horizontal resolution and chemical complexity impact ozone and ozone precursors over CONUS as compared to measurements from five aircraft campaigns, which occurred in 2013. This field campaign analysis demonstrates the importance of using finer horizontal resolution to accurately simulate ozone precursors such as nitrogen oxides and carbon monoxide. In general, the impact of using more complex chemistry on ozone and other oxidation products is more pronounced when using finer horizontal resolution where a larger number of chemical regimes are resolved. Large model biases for ozone near the surface remain in the Southeast US as compared to the aircraft observations even with updated chemistry and finer horizontal resolution. This suggests a need for adding the capability of replacing sections of global emission inventories with regional inventories, increasing the vertical resolution in the planetary boundary layer, and reducing model biases in meteorological variables such as temperature and clouds.
- Published
- 2022
- Full Text
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18. Capability and sensitivity of MPAS-A in simulating tropical cyclones over the South-West Indian Ocean
- Author
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Donkin, Paige T. and Abiodun, Babatunde J.
- Published
- 2023
- Full Text
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19. Numerical Eddy-Resolving Modeling of the Ocean: Mesoscale and Sub-Mesoscale Examples
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E.V. Stanev, M. Ricker, S. Grayek, B. Jacob, V. Haid, and J. Staneva
- Subjects
ocean eddies ,numerical ocean models ,horizontal resolution ,inter-basin exchange ,Oceanography ,GC1-1581 - Abstract
Purpose. The study addresses rotational motion of geophysical fluids in the horizontal and vertical planes. It is aimed mainly at tracing the development of high-resolution numerical modeling of the ocean, as well as at demonstrating new physical processes due to more correct consideration both of the tides in the eddy-resolving numerical models and sub-mesoscale dynamics in the models of the sea straits. Methods and Results. The ocean eddies and their interaction with tides are studied using numerical simulations by four NEMO models for the European North-West shelf with the resolutions ranging from 7 to 1.5 km. The vertical characteristics of motion in the Bosporus Strait were studied using numerical simulations with SCHISM, the unstructured grid model with the ultra-fine model resolution (less than 100 m). The barotropic tidal forcing resulted in substantial flattening of the slopes of the spectral curves. The most important difference between the spectral features of four models occurs in the motion rotational component. In the model with the 1.5 km resolution, the magnitude of the vorticity power spectral density at the scales ~ 70 km is by an order of magnitude higher than in the other three models. Although most of the tidal flattening is associated with the internal tides, beyond a certain horizontal resolution, the eddy dynamics become affected by the barotropic tides. The shelf of the Biscay Bay and the shallows around the Faroe Islands are the most sensitive areas to adding of the barotropic tides to the model forcing. Due to the grid ultra-fine resolution, new elements of physical motion emerged in the Bosporus region. The lateral circulation is dominated by the systems of multiple circulation cells with the scales ~ 1 km. In some areas, the lateral flow magnitude exceeds 0.5 m/s, which is comparable with the magnitude of the axial flow. This reveals importance of the helical elements of the strait circulation for overturning of water masses in the Bosporus. Conclusions. Without proper resolution, the models of tidal oceanic dynamics simulate the ocean general circulation, but do not describe correctly the energy cascades at the eddy scales including interaction between the tides and the mesoscale eddies. Absence of this sub-mesoscale dynamics in the models can largely affect their capability to simulate the two-layer inter-basin exchange.
- Published
- 2020
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20. CMIP6模式水平分辨率对模拟我国西南地区 夏季极端降水的影响评估 .
- Author
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黄子立, 吴小飞, and 毛江玉
- Abstract
Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
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21. 区域气候模式水平分辨率对黄淮海流域 当代气候模拟的影响.
- Author
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石 英, 吴 婕, and 徐 影
- Subjects
- *
CLIMATE extremes , *CLIMATE research , *CLIMATE change models , *ATMOSPHERIC models , *CLIMATE change - Abstract
As a primary tool in climate change research at the watershed scale, the role of horizontal resolution in regional climate simulations needs to be evaluated. This paper investigates the role over the Huang-Huai-Hai (HHH) River basin using a regional climate model, RegCM4, coupled with the National Center for Atmospheric Research (NCAR) Community Land Model, version 4.5 (CLM4.5) including the modules of CN and DV (RCM_CLM4.5). The model is driven by ERA-Interim reanalysis data, and the time period is 1990—2010. Model validation shows that RCM_CLM4. 5 at 50 km and 25 km resolutions can reproduce the present climate well, including the spatial distribution of winter and summer mean temperature and precipitation, the annual cycles of temperature and precipitation, and the climate extremes. However, some biases can also be found. For example, compared with the observation, cold and warm biases are found in the winter and summer mean temperature, respectively; wet biases are found in the precipitation. Comparison between the two simulations, better performance of the magnitude and spatial distribution of mean temperature is found in the simulation at 25 km resolution; while for precipitation, better performance is observed in the one at 50 km resolution; little difference is found for the climate extremes. In general, results from this study indicate a very low sensitivity of present climate in this region to model resolution and can provide a reference for the application of this model in future climate change research over the HHH River basin. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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- View/download PDF
22. Do increasing horizontal resolution and downscaling approaches produce a skillful thunderstorm forecast?
- Author
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Priya, Kumari, Nadimpalli, Raghu, and Osuri, Krishna K.
- Subjects
THUNDERSTORM forecasting ,DOWNSCALING (Climatology) ,THUNDERSTORMS ,METEOROLOGICAL research ,WEATHER forecasting ,HUMIDITY ,NATURAL disaster warning systems - Abstract
The timely prediction of thunderstorms (TS) is always a challenging task for operational and research community. The present study is aimed to address the credibility of the high grid-spacing and downscaling approach for improved simulation of TS. Fourteen TS are simulated with different domain configurations using weather research and forecasting (WRF) model. Two nested domains with 9–3 km (known as DD3), and 6–2 km (DD2), and 3 km single domain (SD3) are considered for simulations. Results indicate that the high-resolution DD2 has improved 2-m temperature (T2), 2-m relative humidity (RH2), and 10-m wind speed (WS10) at different stages of TS. The average mean error of T2 and RH2 in the DD2 experiment is 0.7 °C, − 6% during the mature stage, and 0.2 °C, − 4% at dissipating stage. The error in SD3 and DD3 is relatively higher (9–17% for T2 and 20–60% for RH2). Better horizontal and vertical representation of thermodynamic variables in DD2 run reinforces the atmosphere to initiate and intensify the convection in the right place. The DD2 could show slightly higher instability (convective available potential energy, CAPE, 3188 J kg
−1 ) as compared with DD3 (3164 J kg−1 ) and SD3 (3020 J kg−1 ). The model is biased to simulate early TS activity. DD2 run could simulate the formation, mature and dissipation stages with fewer timing errors (− 1.35 h, − 1.5 h, and − 2.6 h, respectively) than other experiments. The critical success index of the DD2 run is higher for all the rainfall thresholds; however, it is more than 0.2 up to 2.5 mm h−1 . The results highlight that high resolution nested configuration yields better simulation skills than the single domain configuration. [ABSTRACT FROM AUTHOR]- Published
- 2021
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23. On the Importance of High-Resolution in Large-Scale Ocean Models.
- Author
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Chassignet, Eric P. and Xu, Xiaobiao
- Subjects
- *
OCEAN , *SEA ice , *ATMOSPHERIC models , *COMPUTER scientists , *EDDIES , *COMPUTER simulation - Abstract
Eddying global ocean models are now routinely used for ocean prediction, and the value-added of a better representation of the observed ocean variability and western boundary currents at that resolution is currently being evaluated in climate models. This overview article begins with a brief summary of the impact on ocean model biases of resolving eddies in several global ocean–sea ice numerical simulations. Then, a series of North and Equatorial Atlantic configurations are used to show that an increase of the horizontal resolution from eddy-resolving to submesoscale-enabled together with the inclusion of high-resolution bathymetry and tides significantly improve the models' abilities to represent the observed ocean variability and western boundary currents. However, the computational cost of these simulations is extremely large, and for these simulations to become routine, close collaborations with computer scientists are essential to ensure that numerical codes can take full advantage of the latest computing architecture. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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24. Analysis on the effects of different horizontal resolutions and microphysical schemes on the simulation of a rainstorm in central China
- Author
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Zhaoping KANG, Zhiming ZHOU, and Hongli LI
- Subjects
wrf ,horizontal resolution ,microphysical scheme ,ice hydrometeor ,Meteorology. Climatology ,QC851-999 - Abstract
Using the Weather Research and Forecasting (WRF) model, a heavy rainfall in central China during 30 June to 1 Jul 2016 is simulated to explore the effects of different horizontal resolutions and microphysical schemes. The results show that:(1) all of the simulations can reproduce the rainfall well, but simulated rainstorm areas are smaller than observations. The total rainfall is more sensitive to horizontal resolutions than to microphysical schemes, although the big rainstorm is sensitive to both horizontal resolutions and microphysical schemes. With different horizontal resolutions, microphysical schemes and cumulus schemes affect the performance of the rainfall forecast in common. TS scores of 24-hour accumulated precipitation show that the simulation with 12 km horizontal resolution andthe Lin scheme performs the best in extremely rainstorm simulation. (2) The evolution of hydrometeors simulated by different microphysical schemes largely depends on themselves. The Lin scheme simulates more ice and graupel, but less snow. The Thompson scheme simulates more snow, but less ice and graupel. The Morrison shceme simulates the similar contents among three types of ice hydrometeors. The Lin scheme underestimates the ice-water content significantly. The Thompson and Morrison scheme overestimate the ice-water content significantly. (3) Updraft strength simulated by different schemes affects the distribution of hydrometeors in the mature stage. The Lin scheme simulates upright updraft and weak upper flow so that most of the ice hydrometeors are limited in convective system. The Thompson and Morrison schemes simulate slantwise updraft and strong upper flow so that most of ice hydrometeors flow with upper flow.
- Published
- 2019
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25. Decadal Methane Emission Trend Inferred from Proxy GOSAT XCH4 Retrievals: Impacts of Transport Model Spatial Resolution
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Zhu, Sihong, Feng, Liang, Liu, Yi, Wang, Jing, and Yang, Dongxu
- Published
- 2022
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26. Tropical Cyclone Integrated Kinetic Energy in an Ensemble of HighResMIP Simulations.
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Kreussler, Philip, Caron, Louis‐Philippe, Wild, Simon, Loosveldt Tomas, Saskia, Chauvin, Fabrice, Moine, Marie‐Pierre, Roberts, Malcolm J., Ruprich‐Robert, Yohan, Seddon, Jon, Valcke, Sophie, Vannière, Benoît, and Vidale, Pier Luigi
- Subjects
- *
TROPICAL cyclones , *KINETIC energy , *ATMOSPHERIC models , *WIND speed , *CYCLONES - Abstract
This study investigates tropical cyclone integrated kinetic energy, a measure which takes into account the intensity and the size of the storms and which is closely associated with their damage potential, in three different global climate models integrated following the HighResMIP protocol. In particular, the impact of horizontal resolution and of the ocean coupling are assessed. We find that, while the increase in resolution results in smaller and more intense storms, the integrated kinetic energy of individual cyclones remains relatively similar between the two configurations. On the other hand, atmosphere‐ocean coupling tends to reduce the size and the intensity of the storms, resulting in lower integrated kinetic energy in that configuration. Comparing cyclone integrated kinetic energy between a present and a future scenario did not reveal significant differences between the two periods. Plain Language Summary: The damage potential of tropical cyclones is often described by their maximum wind speed. However, maximum wind speed is not particularly well correlated with tropical cyclone losses because intensity defined in such a way does not take into account the size of the storm, which is an important factor driving tropical cyclone related losses. Tropical cyclone integrated kinetic energy on the other hand is a measure which takes into account both the size and the intensity of the cyclones and is more representative of its destructiveness. Here, we investigate integrated kinetic energy in three different global climate models following a common protocol. We find that an increase in horizontal model resolution results in smaller and more intense storms, but that the range of integrated kinetic energy produced by the models remains similar in both configurations. On the other hand, allowing the atmosphere and ocean to interact with each other in the models tends to reduce the size and the intensity of the storms, resulting in lower integrated kinetic energy. Comparing cyclone integrated kinetic energy between present conditions and a projected future climate scenario did not suggest notable changes between the two periods. Key Points: Increasing horizontal resolution leads to smaller and more intense tropical cyclones but relatively similar integrated kinetic energyCoupling atmosphere and ocean tends to reduce the size and intensity of cyclones, generally resulting in lower integrated kinetic energyComparing integrated kinetic energy between present and projected future conditions does not reveal significant differences between the two [ABSTRACT FROM AUTHOR]
- Published
- 2021
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27. Impacts of Horizontal and Vertical Resolutions on the Microphysical Structure and Boundary Layer Fluxes of Typhoon Hato (2017).
- Author
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ZHAO Yang-jie, LI Jiang-nan, LI Fang-zhou, and RUAN Zi-xi
- Subjects
- *
BOUNDARY layer (Aerodynamics) , *WATER vapor transport , *FRICTION velocity , *TYPHOONS , *ICE clouds , *LARGE eddy simulation models - Abstract
We set four sets of simulation experiments to explore the impacts of horizontal resolution (HR) and vertical resolution (VR) on the microphysical structure and boundary layer fluxes of tropical cyclone (TC) Hato (2017). The study shows that higher HR tends to strengthen TC. Increasing VR in the upper layers tends to weaken TC, while increasing VR in the lower layers tends to strengthen TC. Simulated amounts of all hydrometeors were larger with higher HR. Increasing VR at the upper level enhanced the mixing ratios of cloud ice and cloud snow, while increasing VR at the lower level elevated the mixing ratios of graupel and rainwater. HR have greater impact on the distributions of hydrometeors. Higher HR has a more complete ring structure of the eyewall and more concentrated hydrometeors along the cloud wall. Increasing VR at the lower level has little impact on the distribution of TC hydrometeors, while increasing VR at the upper level enhances the cloud thickness of the eyewall area. Surface latent heat flux (SLHF) is influenced greatly by resolution. Higher HR leads to larger water vapor fluxes and larger latent heat, which would result in a stronger TC. A large amount of false latent heat was generated when HR was too high, leading to an extremely strong TC, VR has a smaller impact on SLHF than HR. But increasing VR at the upper-level reduces the SLHF and weakens TC, and elevating VR at the lower-level increases the SLHF and strengthens TC. The changes in surface water vapor flux and SLHF were practically identical and the simulation results were improved when HR and VR were more coordinated. The friction velocity was greater with higher VR. Enhancing VR at the lower level increased the friction velocity, while increasing VR at the upper level reduced it. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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28. Roles of air–sea coupling and horizontal resolution in the climate model simulation of Indian monsoon low pressure systems.
- Author
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Levine, Richard C., Klingaman, Nicholas P., Peatman, Simon C., and Martin, Gill M.
- Subjects
- *
ATMOSPHERIC models , *OCEAN temperature , *MONSOONS , *SIMULATION methods & models , *OCEAN-atmosphere interaction - Abstract
The roles of air–sea coupling and horizontal resolution in the representation of Indian monsoon low pressure systems (LPS) in Met Office Unified Model (MetUM) global climate simulations are investigated. To avoid the generally large sea surface temperature (SST) biases in standard coupled atmosphere–ocean global climate models (GCMs), the analysis is performed on experiments from an atmosphere model coupled to a mixed-layer ocean model (MetUM-GOML2), which allows coupling to be applied regionally as well as globally, while constraining the ocean mean state in coupled regions. Compared to the standard AMIP-style MetUM atmosphere-only simulations, the MetUM-GOML2 simulations produce more monsoon LPS, which is attributed to effects of relatively small remaining (Indian Ocean) SST biases that somewhat strengthen the atmospheric monsoon base state. However, the MetUM-GOML2 simulations, all starting from the same atmospheric and oceanic base state, allow for an idealised approach to evaluate the relative effects of coupling and resolution. When the effects of SST biases are excluded, global coupling has a neutral impact on the number of LPS formed, while the associated rainfall is somewhat reduced due to a local negative air–sea feedback reducing the strength of atmospheric convection and weakening individual LPS. The MetUM-GOML2 simulations show particular sensitivity to localised coupling in the Indian and Pacific Oceans, which appears to enhance the effect of monsoon LPS. Although, in contrast to the global coupling comparison, the comparison of regionally coupled simulations is affected by both differences in interannual SST variability and SST biases, and it is likely that this causes at least part of the positive effects from Indian and Pacific Ocean coupling. More importantly, however, is that the effects of air–sea coupling are substantially smaller than the positive effects of the increase in horizontal resolution from N96 (approx. 200 km) to N216 (approx. 90 km). The resolution effect is also larger than that seen in older MetUM configurations. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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29. Kinetic energy-conserving hyperdiffusion can improve low resolution atmospheric models
- Abstract
© 2015. The Authors. © 2015 American Geophysical Union. P.Z.G is funded by grant CGL2012-30641 by the Ministry of Economy and Research of Spain. The results presented in this work were obtained using the spectral dynamical core available at http://www.gfdl.noaa.gov/fms and the kinetic energy-conserving subgrid scheme described in the manuscript. The output data for all simulations in the paper are stored in the Geophysical Fluid Dynamics Laboratory archive system and can be obtained from the first author (pzurita@alum.mit.edu) upon request. We are grateful to Ed Gerber and an anonymous reviewer for their thorough reviews and pertinent suggestions., Motivated by findings that energetically consistent subgrid dissipation schemes can improve eddy-permitting ocean simulations, this work investigates the impact of the subgrid dissipation scheme on low-resolution atmospheric dynamical cores. A kinetic energy-conserving dissipation scheme is implemented in the model adding a negative viscosity term that injects back into the eddy field the kinetic energy dissipated by horizontal hyperdiffusion. The kinetic energy-conserving scheme enhances numerical convergence when horizontal resolution is changed with fixed vertical resolution and gives superior low-resolution results. Improvements are most obvious for eddy kinetic energy but also found in other fields, particularly with strong or little scale-selective horizontal hyperdiffusion. One advantage of the kinetic energy-conserving scheme is that it reduces the sensitivity of the model to changes in the subgrid dissipation rate, providing more robust results., Ministerio de Economia y Competitividad (MINECO), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub
- Published
- 2023
30. Hurricanes in an aquaplanet world: Implications of the impacts of external forcing and model horizontal resolution
- Author
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Li, F, Collins, WD, Wehner, MF, and Leung, LR
- Subjects
hurricane ,horizontal resolution ,aquaplanet ,climate model ,tropical storm ,Atmospheric Sciences - Abstract
High-resolution climate models have been shown to improve the statistics of tropical storms (TCs) and hurricanes compared to low-resolution models. The impact of increasing horizontal resolution in the TC simulation is investigated exclusively using a series of Atmospheric Global Climate Model (AGCM) runs with idealized aquaplanet steady-state boundary conditions and a fixed operational storm-tracking algorithm. The results show that increasing horizontal resolution helps to detect more hurricanes, simulate stronger extreme rainfall, and emulate better storm structures in the models. However, increasing model resolution does not necessarily produce stronger hurricanes in terms of maximum wind speed, minimum sea-level pressure, and mean precipitation, as the increased number of storms simulated by high-resolution models is mainly associated with weaker storms. The spatial scale at which the analyses are conducted appears to have more important control on these meteorological statistics compared to horizontal resolution of the model grid. When the simulations are analyzed on common low-resolution grids, the statistics of the hurricanes, particularly the hurricane counts, show reduced sensitivity to the horizontal grid resolution and signs of scale invariance. ©2013. American Geophysical Union. All Rights Reserved.
- Published
- 2013
31. Effective resolution in high resolution global atmospheric models for climate studies
- Author
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Remko Klaver, Rein Haarsma, Pier Luigi Vidale, and Wilco Hazeleger
- Subjects
atmospheric models ,global climate models ,horizontal resolution ,Meteorology. Climatology ,QC851-999 - Abstract
Abstract We estimate the extent of spatial scales that atmospheric models in a new generation of global climate models, used in the Coupled Model Intercomparison Project 6, are able to resolve on the basis of kinetic energy spectra, commonly referred to as the effective resolution. We examine the spectra derived from the rotational and divergent parts of the wind for six state‐of‐the‐art global climate models that have been run with at least two horizontal resolutions. For each of the high resolution configurations, the effective resolution enhancement is less than proportional to the increase of the nominal resolution. The highest effective resolution obtained by the models in this study is roughly 200 km. This shows that the newest generation of high resolution climate models starts to resolve synoptic scales relevant for the dynamics of weather events.
- Published
- 2020
- Full Text
- View/download PDF
32. An Idealized Test of the Response of the Community Atmosphere Model to Near‐Grid‐Scale Forcing Across Hydrostatic Resolutions
- Author
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A. R. Herrington and K. A. Reed
- Subjects
GCMs ,horizontal resolution ,idealized tests ,cloud parameterizations ,Physical geography ,GB3-5030 ,Oceanography ,GC1-1581 - Abstract
Abstract A set of idealized experiments are developed using the Community Atmosphere Model (CAM) to understand the vertical velocity response to reductions in forcing scale that is known to occur when the horizontal resolution of the model is increased. The test consists of a set of rising bubble experiments, in which the horizontal radius of the bubble and the model grid spacing are simultaneously reduced. The test is performed with moisture, through incorporating moist physics routines of varying complexity, although convection schemes are not considered. Results confirm that the vertical velocity in CAM is to first‐order, proportional to the inverse of the horizontal forcing scale, which is consistent with a scale analysis of the dry equations of motion. In contrast, experiments in which the coupling time step between the moist physics routines and the dynamical core (i.e., the “physics” time step) are relaxed back to more conventional values results in severely damped vertical motion at high resolution, degrading the scaling. A set of aqua‐planet simulations using different physics time steps are found to be consistent with the results of the idealized experiments.
- Published
- 2018
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- View/download PDF
33. Reflectivity and Resolution Improvement of Underground Rectilinear Objects Detection Using GPR.
- Author
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Bilik, Y., Haridim, M., and Bilik, D.
- Abstract
In our previous works, we presented a fundamentally new method for detecting underground rectilinear objects by means of georadars. To improve the lateral resolution of the proposed method, a variant of this method using two transmitting antennas fed in antiphase was proposed. In this letter, we extend the previous work and present a deeper analysis of this method. It is shown that using the proposed method, a significant increase in both the relative area reflectivity (RAR) of rectilinear objects and the lateral resolution in the detection of underground narrow objects can be achieved. Our calculations show that using this method, it is possible to achieve a high horizontal resolution of the order of 0.2 m at depths of 20–30 m. The dependencies of RAR on the object’s depth and width are calculated and presented. This method is applicable for both orthogonal and any other scanning scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
34. Effective resolution in high resolution global atmospheric models for climate studies.
- Author
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Klaver, Remko, Haarsma, Rein, Vidale, Pier Luigi, and Hazeleger, Wilco
- Subjects
- *
ATMOSPHERIC models , *KINETIC energy - Abstract
We estimate the extent of spatial scales that atmospheric models in a new generation of global climate models, used in the Coupled Model Intercomparison Project 6, are able to resolve on the basis of kinetic energy spectra, commonly referred to as the effective resolution. We examine the spectra derived from the rotational and divergent parts of the wind for six state‐of‐the‐art global climate models that have been run with at least two horizontal resolutions. For each of the high resolution configurations, the effective resolution enhancement is less than proportional to the increase of the nominal resolution. The highest effective resolution obtained by the models in this study is roughly 200 km. This shows that the newest generation of high resolution climate models starts to resolve synoptic scales relevant for the dynamics of weather events. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
35. On the probabilistic skill of dual‐resolution ensemble forecasts.
- Author
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Leutbecher, Martin and Ben Bouallègue, Zied
- Subjects
- *
LONG-range weather forecasting , *MULTILEVEL models , *FORECASTING , *NUMERICAL weather forecasting , *ABILITY , *WEATHER forecasting - Abstract
Increasing spatial resolution and increasing ensemble size both tend to improve the skill of ensemble forecasts. Due to computational constraints, a balance needs to be found in operational NWP. Here, we examine a scenario where ensembles are formed by pooling k lower‐resolution and m higher‐resolution members such that the overall computational cost is equal to the constraint. The approach is applied to medium‐range weather forecasts with ECMWF's Integrated Forecasting System using horizontal resolutions of 18, 29 and 45 km and ensemble sizes ranging from 8 to 254 members. The methodology is similar to the multi‐level Monte‐Carlo approach but does not use stochastic perturbations that are shared between members at different levels. Probabilistic skill is quantified for 850 hPa temperature verified against analyses and 2 m temperature verified against station observations. Generally, dual‐resolution ensembles with similar numbers of lower and higher‐resolution members provide the optimal configuration for 2 m temperature prediction. In contrast, single‐resolution ensembles appear to be the most skilful for 850 hPa temperature. The dual‐resolution ensembles are a special kind of multi‐model ensemble. An analytic model describing the skill of such a multi‐model ensemble is developed and its parameters are estimated from the actual verification statistics. The model is capable of describing the general differences in behaviour between 2 m temperature and 850 hPa temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
36. Improved representation of the diurnal variation of warm season precipitation by an atmospheric general circulation model at a 10 km horizontal resolution.
- Author
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Kim, Hyerim, Lee, Myong-In, Cha, Dong-Hyun, Lim, Young-Kwon, and Putman, William M.
- Subjects
- *
GENERAL circulation model , *METEOROLOGICAL precipitation , *ATMOSPHERIC circulation , *MESOSCALE convective complexes , *HUMIDITY , *RELIEF models - Abstract
This study investigates the diurnal variation of the warm season precipitation simulated by the Goddard Earth Observing System version 5 atmospheric general circulation model for 2 years (2005–2006) at a horizontal resolution of 10 km. The simulation was validated with the satellite-derived Tropical Rainfall Measuring Mission (TRMM) 3B42 precipitation data and the Modern-Era Retrospective analysis for Research and Applications atmospheric reanalysis for atmospheric winds and moisture. The simulation is compared with the coarse-resolution run in 50 km to examine the impacts driven by resolution change. Overall, the 10 km model tends to reproduce the important features of the observed diurnal variation, such as the amplitude and phase at which precipitation peaks in the evening on land and in the morning over the ocean, despite an excessive amplitude bias over land. The model also reproduces the realistic propagation patterns of precipitation in the vicinity of ocean coasts and major mountains. The regional characteristics of the diurnal precipitation over two regions, the Bay of Bengal and the Great Plains in North America, are examined in detail, where the observed diurnal cycle exhibits a systematic transition in the peak phase due to the development and propagation of regional-scale convective systems. The model is able to reproduce this pattern as well as the diurnal variation of low-level wind and moisture convergence; however, it is less effective at representing the nocturnal peak of precipitation over the Great Plains. The model results suggest that increasing the horizontal resolution of the model to 10 km substantially improves the representation of the diurnal precipitation cycle. However, intrinsic model deficiencies in topographical precipitation and the accurate representation of mesoscale convective systems remain a challenge. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
37. Revisiting the effect of increasing horizontal resolution on the evolution of El Niño in a coupled model.
- Author
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Arora, Anika
- Subjects
- *
SOUTHERN oscillation , *ZONAL winds , *OCEAN temperature , *OCEAN-atmosphere interaction , *MONSOONS ,EL Nino - Abstract
The ENSO (El Niño southern oscillation) in the tropical Pacific plays a crucial role in regulating the Indian summer monsoon. Many mechanisms have been proposed to explain the positive and negative feedback associated with the ENSO through air-sea interaction in the tropical Pacific. Historical run data at varying oceanic and atmospheric resolutions from the MPI-ESM model is analyzed and compared with observations to determine the possible reasons for the much earlier onset and delayed withdrawal of ENSO in the coupled model. Increasing the resolution of the oceanic and atmospheric components of the coupled model helps in well-resolving the annual cycle of sea surface temperature in the tropical Pacific. There is a significant improvement in the early onset and late withdrawal of El Niño in the coupled model with increasing horizontal resolution of the model components. The weak subsurface propagation along the 20 °C isotherm in the equatorial Pacific improves on increasing the horizontal resolution of the coupled model. Similar to observations, there is a clear eastward extension of convection, 20° east of the dateline, in the equatorial tropical Pacific in the coupled model during ENSO years. Increasing the resolution of the oceanic and atmospheric components of the coupled model improves the simulation of convective activity over the western Pacific along with the improved magnitude of anomalous zonal wind strength during El Niño years. However, the presentation of convective activity over the equatorial Pacific deteriorated on increasing atmospheric resolution further to T255 due to the enhanced value of the interannual amplitude of intraseasonal zonal wind around the international dateline. Also, the coupled model does not capture the accurate eastward propagation of the Madden Julian Oscillation envelope over the western Pacific. While higher resolutions showed improvement in the representation of El Niño events in terms of their number and duration, challenges persisted in accurately capturing the frequency of these events and their related triggering mechanisms. Understanding the intricate interplay of factors influencing the evolution of El Niño requires further research and progress in modeling strategies. • Historical data of MPI-ESM model is analyzed to understand earlier onset and delayed withdrawal of ENSO in a coupled model. • There is a clear eastward extension of convection in the PO in the coupled model during ENSO years, like observations. • Increasing the horizontal resolution of the coupled model improves the simulation of convective activity over the western PO. • Convective activity over PO deteriorated on increasing resolution to T255 due to increase ininterannual amplitude of intraseasonal zonal wind. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Does Increasing Model Resolution Improve the Real-Time Forecasts of Western North Pacific Tropical Cyclones?
- Author
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Jihong Moon, Jinyoung Park, and Dong-Hyun Cha
- Subjects
tropical cyclone forecast ,WRF ,horizontal resolution ,moving nesting ,the western North Pacific tropical cyclones ,Meteorology. Climatology ,QC851-999 - Abstract
In this study, the general impact of high-resolution moving nesting domains on tropical cyclone (TC) intensity and track forecasts was verified, for a total of 107 forecast cases of 33 TCs, using the Weather Research and Forecasting (WRF) model. The experiment, with a coarse resolution of 12 km, could not significantly capture the intensification process, especially for maximum intensities (>60 m s−1). The intense TCs were better predicted by experiments using a moving nesting domain with a horizontal resolution of 4 km. The forecast errors for maximum wind speed and minimum sea-level pressure decreased in the experiment with higher resolution; the forecast of lifetime maximum intensity was improved. For the track forecast, the experiment with a coarser resolution tended to simulate TC tracks deviating rightward to the TC motions in the best-track data; this erroneous deflection was reduced in the experiment with a higher resolution. In particular, the track forecast in the experiment with a higher resolution improved more frequently for intense TCs that were generally distributed at relatively lower latitudes among the test cases. The sensitivity of the track forecast to the model resolution was relatively significant for lower-latitude TCs. On the other hand, the track forecasts of TCs moving to the mid-latitudes, which were primarily influenced by large-scale features, were not sensitive to the resolution.
- Published
- 2021
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39. Simulation of Pre-monsoon Cyclones of Two Contrasting Monsoon Years Using Mesoscale Model WRF (ARW)
- Author
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Ramakrishna, Surireddi S. V. S., Srinivas, C. V., Sravani, A., Rao, N. Nanaji, Rao, V. Lakshmana, Saradhi, N. Vijaya, Mohanty, U. C., editor, Mohapatra, M., editor, Singh, O. P., editor, Bandyopadhyay, B. K., editor, and Rathore, L. S., editor
- Published
- 2014
- Full Text
- View/download PDF
40. The Sensitivity of Euro‐Atlantic Regimes to Model Horizontal Resolution.
- Author
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Strommen, K., Mavilia, I., Corti, S., Matsueda, M., Davini, P., Hardenberg, J., Vidale, P.‐L., and Mizuta, R.
- Subjects
- *
ATMOSPHERIC circulation , *CIRCULATION models , *ATMOSPHERIC structure , *DOCUMENT clustering , *SPATIOTEMPORAL processes - Abstract
There is growing evidence that the atmospheric dynamics of the Euro‐Atlantic sector during winter is driven in part by the presence of quasi‐persistent regimes. However, general circulation models typically struggle to simulate these with, for example, an overly weakly persistent blocking regime. Previous studies have showed that increased horizontal resolution can improve the regime structure of a model but have so far only considered a single model with only one ensemble member at each resolution, leaving open the possibility that this may be either coincidental or model dependent. We show that the improvement in regime structure due to increased resolution is robust across multiple models with multiple ensemble members. However, while the high‐resolution models have notably more tightly clustered data, other aspects of the regimes may not necessarily improve and are also subject to a large amount of sampling variability that typically requires at least three ensemble members to surmount. Key Points: Climate models have difficulty representing Euro‐Atlantic regime structure correctlyIncreasing horizontal resolution improves the significance of regime clustering across multiple modelsSpatial patterns and persistence levels of regimes do not necessarily improve with increased resolution [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
41. Response of Indian monsoon to increase of resolution in NCAR-CAM5.
- Author
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Anand, Abhishek, Bhowmick, Mansi, Mishra, Saroj K., Sahany, Sandeep, and Reddy Telukuntla, Chanakya V.
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MONSOONS , *EARTH temperature , *HUMIDITY , *ATMOSPHERIC models , *DIURNAL variations in meteorology - Abstract
Abstract Effects of increase in horizontal resolution (from 2°, to 1° and 0.5°) in simulating Indian summer monsoon (ISM) in Community Atmosphere Model version 5 (CAM5) are reported herein. Various parameters — temperature, rainfall, winds, surface evaporation, precipitable water, specific humidity, and clouds — of the model simulations are examined with respect to observations {India Meteorological Department (IMD) and Tropical Rainfall Measuring Mission (TRMM) data for precipitation and Modern-Era Retrospective analysis for Research and Applications (MERRA) products for rest of the variables}. With increase in horizontal resolution overall improvement in majority of surface driven parameters like surface air temperature, surface specific humidity, and low-level winds is observed that highlights the importance of better representation of orography. Over the Indian subcontinent and surrounding oceans, rainfall is overestimated due to the overestimation of the large-scale precipitation in the model, which significantly gets alleviated with increase in resolution. Overall, seasonal mean features of ISM show significant improvements, which are likely to further improve by representing finer spatial features with increase in resolution. However, some aspects of its temporal variations — seasonal, intraseasonal, and diurnal variations — of monsoon rainfall do not show much improvement with increase in resolution, suggesting that traditional physics parameterizations do not work well at high resolution and hence there is a need for improvement in model physics. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
42. THE IMPACT OF HORIZONTAL RESOLUTION ON THE INTENSITY AND MICROSTRUCTURE OF SUPER TYPHOON USAGI.
- Author
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WEN Ying-fang, LIU Yu-di, TAN Wei-cai, PENG Ke-man, and CHEN Hai-feng
- Subjects
- *
TYPHOONS , *MICROSTRUCTURE , *SIMULATION methods & models - Abstract
Typhoon Usagi (1319) was simulated by using the Advanced Weather Research and Forecasting numerical model (WRF) with different horizontal resolution to understand the impact of horizontal resolution on the intensity and characteristics of typhoon's microstructures (including dynamic and microphysical structure). The simulated results show that the improvement of horizontal resolution from 5 km to 1 km has little impact on the track which is comparable to real results, but has a significant impact on the intensity and microstructures, and especially, the impact on wind speed at 10 m height, the vertical movement and precipitation intensity is the greatest. When the resolution is increased to 1 km, the intensity and characteristics of typhoon's microstructures can be simulated better. In lower resolution simulations, some structural characteristics, including more asymmetrical and more outward tilted eyewall, and less water vapor flux on sea surfuce, work together to weaken typhoon intensity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
43. How well is Rossby wave activity represented in the PRIMAVERA coupled simulations?
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Susanna Corti, F. Fabiano, and Paolo Ghinassi
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Horizontal resolution ,General Circulation Model ,Climatology ,Meteorology. Climatology ,Metric (mathematics) ,Resolution (electron density) ,Northern Hemisphere ,Rossby wave ,Transient waves ,QC851-999 ,Spatial distribution ,Geology - Abstract
This work aims to assess the performance of state-of-the-art global climate models in representing the upper-tropospheric Rossby wave pattern in the Northern Hemisphere and over the European–Atlantic sector. A diagnostic based on finite-amplitude local wave activity is used as an objective metric to quantify the amplitude of Rossby waves in terms of Rossby wave activity. This diagnostic framework is applied to a set of coupled historical climate simulations at different horizontal resolutions, performed in the framework of the PRIMAVERA project and compared with observations (ERA5 reanalysis). At first, the spatio-temporal characteristics of Rossby wave activity in the Northern Hemisphere are examined in the multimodel mean of the whole PRIMAVERA set. When examining the spatial distribution of transient wave activity, only a minimal improvement is found in the high-resolution ensemble. On the other hand, when examining the temporal variability of wave activity, a higher resolution is beneficial in all models apart from one. In addition, when examining the Rossby wave activity time series, no evident trends are found in the historical simulations (at both standard and high resolutions) and in the observations. Finally, the spatial distribution of Rossby wave activity is investigated in more detail focusing on the European–Atlantic sector, examining the wave activity pattern associated with weather regimes for each model. Results show a marked inter-model variability in representing the correct spatial distribution of Rossby wave activity associated with each regime pattern, and an increased horizontal resolution improves the models' performance only for some of the models and for some of the regimes. A positive impact of an increased horizontal resolution is found only for the models in which both the atmospheric and oceanic resolution is changed, whereas in the models in which only the atmospheric resolution is increased, a worsening model performance is detected.
- Published
- 2022
44. 厚壁管道周向压电Lamb波缺陷图像增强研究.
- Author
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王立, 陈果, 石文泽, 卢超, and 陈尧
- Abstract
Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
45. Assessment of prediction skill in equatorial Pacific Ocean in high resolution model of CFS.
- Author
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Arora, Anika, Rao, Suryachandra A., Pillai, Prasanth, Dhakate, Ashish, Salunke, Kiran, and Srivastava, Ankur
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SOUTHERN oscillation , *ATMOSPHERIC circulation , *ATMOSPHERIC models , *MATHEMATICAL models of atmospheric circulation ,EL Nino - Abstract
The effect of increasing atmospheric resolution on prediction skill of El Niño southern oscillation phenomenon in climate forecast system model is explored in this paper. Improvement in prediction skill for sea surface temperature (SST) and winds at all leads compared to low resolution model in the tropical Indo-Pacific basin is observed. High resolution model is able to capture extreme events reasonably well. As a result, the signal to noise ratio is improved in the high resolution model. However, spring predictability barrier (SPB) for summer months in Nino 3 and Nino 3.4 region is stronger in high resolution model, in spite of improvement in overall prediction skill and dynamics everywhere else. Anomaly correlation coefficient of SST in high resolution model with observations in Nino 3.4 region targeting boreal summer months when predicted at lead times of 3-8 months in advance decreased compared its lower resolution counterpart. It is noted that higher variance of winds predicted in spring season over central equatorial Pacific compared to observed variance of winds results in stronger than normal response on subsurface ocean, hence increases SPB for boreal summer months in high resolution model. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
46. Resolved gravity waves in the tropical stratosphere: Impact of horizontal resolution and deep convection parametrization
- Author
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Inna Polichtchouk, Nils Wedi, and Young-Ha Kim
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Convection ,Horizontal resolution ,Atmospheric Science ,Deep convection ,Gravitational wave ,Mesoscale meteorology ,Geophysics ,Parametrization ,Stratosphere ,Geology - Published
- 2021
47. Drivers of exceptional coastal warming in the northeastern United States
- Author
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Ambarish V. Karmalkar and Radley M. Horton
- Subjects
Horizontal resolution ,Sea surface temperature ,North Atlantic oscillation ,Atmospheric circulation ,Climatology ,Hotspot (geology) ,High spatial resolution ,Environmental science ,Common spatial pattern ,Climate model ,Environmental Science (miscellaneous) ,Social Sciences (miscellaneous) - Abstract
The northeastern United States (NEUS) and the adjacent Northwest Atlantic Shelf (NWS) have emerged as warming hotspots, but the connection between them remains unexplored. Here we use gridded observational and reanalysis datasets to show that the twentieth-century surface air temperature increase along the coastal NEUS is exceptional on the continental and hemispheric scale and is induced by a combination of two factors: the sea surface temperature (SST) increase in the NWS associated with a weakening Atlantic Meridional Overturning Circulation (AMOC), and atmospheric circulation changes associated with a more persistent positive North Atlantic Oscillation. These connections are important because AMOC slowdown and NWS warming are projected to continue. A survey of climate model simulations indicates that realistic SST representation at high spatial resolution might be a minimum requirement to capture the observed pattern of coastal warming, suggesting that prior projection-based assessments may not have captured key features in this populous region. The coastal northeastern United States is a warming hotspot, and observations identify a slower Atlantic overturning circulation and a positive North Atlantic Oscillation phase as drivers. Analysis suggests that low horizontal resolution probably hampers models’ ability to capture the spatial pattern of enhanced warming.
- Published
- 2021
48. Sensitivity study of the REMO regional climate model to domain size
- Author
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Réka Suga, Gabriella Allaga-Zsebeházi, and Otília A. Megyeri-Korotaj
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Horizontal resolution ,Atmospheric Science ,Ecological Modeling ,Science ,Physics ,QC1-999 ,Model domain ,Pollution ,Domain (software engineering) ,Geophysics ,General Circulation Model ,Climatology ,Meteorology. Climatology ,Environmental science ,Climate model ,Precipitation ,Sensitivity (control systems) ,QC851-999 - Abstract
In the framework of the KlimAdat national project, the Hungarian Meteorological Service (OMSZ) is aiming to perform 10 km horizontal resolution simulations with the 2015 version of the REMO regional climate model over Central and Eastern Europe. The long-term simulations were preceded by a 10-year long sensitivity study on domain size, which is summarised in this paper. We selected three different domains embedded in each other, which contain the whole area of the Danube and Tisza river catchments. Lateral boundary conditions were obtained from the 50 km resolution REMO driven by the MPI-ESM-LR global climate model. Simulations were performed for the period of 1970–1980 including 1-year spin-up. Monthly and seasonal means of daily 2 m temperature, precipitation sum and several precipitation indices were evaluated. Reference datasets were E-OBS 19.0 and CarpatClim-HU. We can conclude, that the selection of domain size has a larger impact on the simulation of precipitation, and in the case of the seasonal mean of the precipitation indices, the differences amongst the results obtained on each model domain exceed 10 %. In general, the smallest biases occurred on the largest domain, therefore further long-term simulations are being produced on this domain.
- Published
- 2021
49. Role of PBL and Microphysical Parameterizations During WRF Simulated Monsoonal Heavy Rainfall Episodes Over Mumbai
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Sudhansu S. Rath, Jagabandhu Panda, and Saurabh Verma
- Subjects
Horizontal resolution ,Convection ,Boundary layer ,Geophysics ,Microphysics ,Geochemistry and Petrology ,Planetary boundary layer ,Weather Research and Forecasting Model ,Climatology ,Environmental science ,Monsoon ,Temporal scales - Abstract
Monsoon circulation and associated rainfall add complexities in the boundary layer features over the Indian subcontinents. Besides relevant microphysical variables, the characteristics of various boundary layer parameters and their variations at differing spatial and temporal scales are investigated over Mumbai during monsoonal heavy rainfall scenarios. During the summer monsoon months (June to September) of 2014–2018, 16 heavy rainfall cases are chosen for this study. High-resolution simulation is conducted with three nested domains having a horizontal resolution of 18, 6, and 2 km with the 35 vertical levels in the advanced research WRF (WRF-ARW) model. The sensitivity experiment is carried out with seven planetary boundary layer (PBL) schemes; non-local first-order closure [Yonsei University (YSU), Asymmetric convective model, version 2 (ACM2), and Shin-Hong], local one-and-a-half order [Mellor–Yamada–Janjic (MYJ), quasi-normal scale elimination (QNSE), Bougeault–Lacarrere (BouLac), and Grenier-Bretherton-McCaa (GBM)] and five microphysics (MP) schemes [WSM6, Goddard, WDM6, Thompson, and Lin et al.]. PBL parameterization in combination with the Lin et al. scheme shows a significant impact on rainfall and dynamical and thermodynamical parameters at the surface and the upper levels. QNSE showed a relatively deeper and warmer atmospheric boundary layer compared to others to support strong upper-level divergence and high moisture content within the lower levels. Based on the results, QNSE is found to have a relatively better skill for representing the conducive environment, and Lin et al. microphysics could accommodate the same for the occurrence of the intense monsoonal rainfall events over Mumbai. The said combination is possibly effective for other coastal areas of India for better prediction of intense monsoonal rainfall episodes as well.
- Published
- 2021
50. Wind resource assessment and energy potential of selected locations in Fiji
- Author
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Gilles Bellon, Rajnish N. Sharma, Michael Kingan, John Cater, Kunal K. Dayal, University of Auckland [Auckland], Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Horizontal resolution ,Resource (biology) ,060102 archaeology ,Meteorology ,Renewable Energy, Sustainability and the Environment ,020209 energy ,06 humanities and the arts ,02 engineering and technology ,Wind direction ,7. Clean energy ,Turbine ,Wind speed ,0202 electrical engineering, electronic engineering, information engineering ,Wind resource assessment ,Environmental science ,0601 history and archaeology ,Resource assessment ,Energy (signal processing) - Abstract
International audience; This study summarizes an assessment of the wind resource at selected locations in Fiji for the potential of future utility-scale wind-power development. We use 2-8 years of near surface wind observations (2011-2018) from thirty automatic weather stations. The standard windindustry software, WAsP is used to simulate the wind resource in terms of mean wind speed, dominant wind direction, power density and annual energy production (AEP) using a Vergnet 275-kW wind turbine. Our analysis identifies three sites: Rakiraki, Nabouwalu and Udu, which should be considered for a future comprehensive resource assessment for utility-scale windpower development once further wind resource data is available. High-resolution resource maps for each wind resource parameter at a horizontal resolution of 50 m are produced for 6 km × 6 km domains around these sites. Rakiraki, Nabouwalu and Udu have average wind speeds of 7.6 m/s, 7.1 m/s and 7.0 m/s, with an average power density of 401 W/m 2 , 512 W/m 2 and 294 W/m 2 , and a potential average AEP of 0.91 GWh, 0.80 GWh and 0.72 GWh at 55 m AGL, respectively. The dominant wind direction is southeasterly. Modelling a 10 MW wind farm at each site yields a net AEP of 43 GWh, 42 GWh and 37 GWh for Rakiraki, Nabouwalu and Udu, respectively with capacity factors of 0.42-0.48 and wind farm efficiencies of 97-98 %.
- Published
- 2021
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