472 results
Search Results
2. GCM Security Bounds Reconsidered
- Author
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Niwa, Yuichi, Ohashi, Keisuke, Minematsu, Kazuhiko, Iwata, Tetsu, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, and Leander, Gregor, editor
- Published
- 2015
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3. Comb to Pipeline: Fast Software Encryption Revisited
- Author
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Bogdanov, Andrey, Lauridsen, Martin M., Tischhauser, Elmar, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, and Leander, Gregor, editor
- Published
- 2015
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4. COBRA: A Parallelizable Authenticated Online Cipher Without Block Cipher Inverse
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Andreeva, Elena, Luykx, Atul, Mennink, Bart, Yasuda, Kan, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Cid, Carlos, editor, and Rechberger, Christian, editor
- Published
- 2015
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5. The Security and Performance of 'GCM' when Short Multiplications Are Used Instead
- Author
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Aoki, Kazumaro, Yasuda, Kan, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Kutyłowski, Mirosław, editor, and Yung, Moti, editor
- Published
- 2013
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6. FPGA-Based High-Speed Authenticated Encryption System
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Muehlberghuber, Michael, Keller, Christoph, Gürkaynak, Frank K., Felber, Norbert, Burg, Andreas, editor, Coṣkun, Ayṣe, editor, Guthaus, Matthew, editor, Katkoori, Srinivas, editor, and Reis, Ricardo, editor
- Published
- 2013
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7. Projection of Climate Change for South East Europe and Related Impacts
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Bruci, Eglantina, Alexandrov, Vesselin, editor, Gajdusek, Martin Felix, editor, Knight, C. Gregory, editor, and Yotova, Antoaneta, editor
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- 2010
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8. The Software Performance of Authenticated-Encryption Modes
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Krovetz, Ted, Rogaway, Phillip, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, and Joux, Antoine, editor
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- 2011
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9. GCM Variants with Robust Initialization Vectors.
- Author
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Zhang, Ping
- Subjects
COMPUTER network security ,COMPUTER network protocols ,TELECOMMUNICATION systems ,ISOMERIZATION - Abstract
The complexity and isomerization of communication networks have put forth new requirements for cryptographic schemes to ensure the operation of network security protocols. Robust cryptographic schemes have been gradually favored. The robust initialization vector (RIV) instead of the synthetic initialization vector (SIV) was first introduced to support strong security and robust authenticated encryption. This paper first introduces RIV to GCM-SIV1, proposes a robust variant, GCM-RIV1, and proves that it ensures birthday-bound subtle AE (SAE) security and nonce-misuse resistance. Then, to support beyond-birthday-bound (BBB) security with graceful degradation, we introduce another, stronger security variant, GCM-RIV2, and prove that it allows gracefully degrading BBB SAE security in the faulty nonce setting. Finally, the performance of GCM-RIV1 and GCM-RIV2 is discussed and compared. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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10. The uniqueness of ruminants (Ruminantia) among the even-toed ungulates (Artiodactyla): Part I: Molecular baraminology studies.
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Lightner, Jean K. and Cserhati, Matyias
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ARTIODACTYLA ,RUMINANTS ,BATS ,LANDFILLS - Abstract
Though evolutionists routinely assume universal common descent of life, observational evidence militates against this unsubstantiated belief. In contrast, creationists recognize limited common descent where originally created kinds of organisms have reproduced to fill the earth. As they have done so, there has been considerable diversification and adaptation, though not enough to transmute them into a fundamentally different type of organism (e.g., from a rodent to a bat). Organisms that are not related by common descent can be recognized by significant holistic discontinuity between them. In this paper we begin an investigation of ruminants (Ruminantia), members of the order Artiodactyla, to determine if there is significant discontinuity between them and other species within this order. In this first paper, two molecular baraminology techniques were applied to available data to determine the relationship of ruminants to other artiodactyls. The results support the hypothesis that ruminants do not share common ancestry with other artiodactyls. [ABSTRACT FROM AUTHOR]
- Published
- 2023
11. Downscaled GCM climate projections of fire weather over Victoria, Australia. Part 1*: evaluation of the MACA technique.
- Author
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Clark, Scott, Mills, Graham, Brown, Timothy, Harris, Sarah, and Abatzoglou, John T.
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FIRE weather ,GENERAL circulation model ,EFFECT of human beings on climate change ,FIRE risk assessment ,PRESCRIBED burning ,FOREST fires - Abstract
Anthropogenic climate change is expected to cause an increase in fire danger over south-eastern Australia during the 21st century, primarily driven by increased surface temperature. Studies of future fire weather in Victoria, Australia, have so far mostly utilised direct output from general circulation models, which have inadequate resolution for resolving the dynamics of local fire danger and are prone to substantial biases that may affect the seasonality of dry fuels. In this paper, we assess the ability of the Multivariate Adaptive Constructed Analogs (MACA) method to downscale output from general circulation models over Victoria, and replicate statistical attributes of fire danger indices. We find that climatological descriptors of meteorological variables of wind, temperature and humidity are captured extremely well, and fields on extreme fire days are well captured. We find that the method works very well for statistically downscaling fire weather elements over Victoria and provides a vehicle to assess the regional variation of fire weather projections over Victoria. This paper evaluates the computationally efficient Multivariate Adaptive Constructed Analogs (MACA) method for downscaling a single general circulation model to a fine scale over the state of Victoria, Australia. Comparison with a 4-km fire weather climatology dataset shows the method well reproduces observed statistics of mean and extreme fire weather. Photo showing planned burn in Victoria, Australia, by Tim Brown. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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12. Improved Modeling of Mars' HDO Cycle Using a Mars' Global Climate Model.
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Vals, Margaux, Rossi, Loïc, Montmessin, Franck, Lefèvre, Franck, Gonzalez‐Galindo, Francisco, Fedorova, Anna, Luginin, Mikhail, Forget, François, Millour, Ehouarn, Korablev, Oleg, Trokhimovskiy, Alexander, Shakun, Alexey, Bierjon, Antoine, and Montabone, Luca
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ATMOSPHERIC models ,GENERAL circulation model ,ATMOSPHERIC chemistry ,MARS (Planet) ,ICE clouds ,ATMOSPHERIC water vapor measurement ,ATMOSPHERE - Abstract
HDO and the D/H ratio are essential to understand Mars past and present climate, in particular with regard to the evolution through ages of the Martian water cycle. We present here new modeling developments of the HDO cycle with the Laboratoire de Météorologie Dynamique Mars Global Climate Model (GCM). The present study aims at exploring the behavior of the D/H ratio cycle and its sensitivity to the modeling of water ice clouds and the formulation of the fractionation by condensation. Our GCM simulations are compared with observations provided by the Atmospheric Chemistry Suite (ACS) on board the ESA/Roscosmos Trace Gas Orbiter (TGO), and reveal that the model quite well reproduces the temperature and water vapor fields, which offers a good basis for representing the D/H ratio cycle. The comparison also emphasizes the importance of modeling the state of supersaturation, resulting from the microphysical processes of water ice clouds, to correctly account for the water vapor and the D/H ratio of the middle‐to‐upper atmosphere. This work comes jointly with a detailed comparison of the measured D/H profiles by TGO/ACS and the model outputs, conducted in the companion paper of Rossi et al. (2022, https://doi.org/10.1029/2022JE007201) (this issue). Plain Language Summary: The D/H ratio observed in a planetary atmosphere is traditionally used as a proxy to estimate the initial water reservoir of the planet. We present here an improved global circulation model including HDO, the main isotope of water on Mars. The updated model takes into account the details of the formation of clouds and their radiative effect. It also includes the effect of photochemistry on HDO and deuterated species. We find that supersaturation is key to the representation of the D/H cycle by making the hygropause more porous, allowing more HDO in the upper atmosphere. It also reduces the efficiency of the isotopic fractionation occurring at condensation. We present here comparisons between observations by the Atmospheric Chemistry Suite spectrometer onboard the orbiter TGO. While the model is globally in agreement with the observations, the inability of the model to reproduce the observed vertical distribution of dust, especially during the Global Dust Storm, causes discrepancies in the representation of water vapor. The model reveals the importance of representing the state of supersaturation to correctly account for the water vapor amount reaching the top of the atmosphere and estimate the D/H ratio at escape. Key Points: The HDO cycle has been implemented in the last version of the Laboratoire de Météorologie Dynamique Mars Global Climate Model including microphysics and radiative effect of water ice cloudsKinetics effect is now included in HDO fractionation during condensation and proves to be significantSupersaturation, the presence of which is regulated by cloud processes, alters significantly the relative abundances of HDO and H2O [ABSTRACT FROM AUTHOR]
- Published
- 2022
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13. Simulating Changes in Hydrological Extremes—Future Scenarios for Morocco.
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Giustarini, Laura, Schumann, Guy J. -P., Kettner, Albert J., Smith, Andrew, and Nawrotzki, Raphael
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CLIMATE change ,EXTREME environments ,TIME series analysis ,FLOODS - Abstract
This paper presents a comprehensive river discharge analysis to estimate past and future hydrological extremes across Morocco. Hydrological simulations with historical forcing and climate change scenario inputs have been performed to better understand the change in magnitude and frequency of extreme discharge events that cause flooding. Simulations are applied to all major rivers of Morocco, including a total of 16 basins that cover the majority of the country. An ensemble of temperature and precipitation input parameter sets was generated to analyze input uncertainty, an approach that can be extended to other regions of the world, including data-sparse regions. Parameter uncertainty was also included in the analyses. Historical simulations comprise the period 1979–2021, while future simulations (2015–2100) were performed under the Shared Socioeconomic Pathway (SSP) 2–4.5 and SSP5–8.5. Clear patterns of changing flood extremes are projected; these changes are significant when considered as a proportion of the land area of the country. Two types of basins have been identified, based on their different behavior in climate change scenarios. In the Northern/Mediterranean basins we observe a decrease in the frequency and intensity of events by 2050 under both SSPs, whereas for the remaining catchments higher and more frequent high-flow events in the form of flash floods are detected. Our analysis revealed that this is a consequence of the reduction in rainfall accumulation and intensity in both SSPs for the first type of basins, while the opposite applies to the other type. More generally, we propose a methodology that does not rely on observed time series of discharge, so especially for regions where those do not exist or are not available, and that can be applied to undertake future flood projections in the most data-scarce regions. This method allows future hydrological hazards to be estimated for essentially any region of the world. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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14. Building Adaptation Measures Using Future Climate Scenarios—A Scoping Review of Uncertainty Treatment and Communication.
- Author
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Gaarder, Jørn Emil, Hygen, Hans Olav, Bohne, Rolf André, and Kvande, Tore
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CLIMATE change models ,SCIENTIFIC literature ,METEOROLOGICAL research ,CLIMATE change ,LITERARY adaptations - Abstract
The global climate is changing. Predicting the impacts this will have on buildings is the first step in the process of finding suitable building adaptation measures. Future climate adaptation of buildings and infrastructure is a growing field of research, relying on both socio-economical and meteorological research for input values to the simulation models. Models producing hourly future weather data rely on global climate models which are based on emission scenarios made from assumptions of future political, social, and economic developments. Accounting for the uncertainties from these underlying models as much as possible, and communicating the uncertainties in the results, is obviously paramount for reliable conclusions from the building simulation models. This paper is a scoping review, investigating how 132 studies treat and communicate the string of uncertainties from underlying models connected to future weather file generation in the scientific literature on building adaptation research. The findings suggest that climate-model-induced uncertainties are often under-communicated, due to either insufficient analysis or neglect. The studies that included the most comprehensive analyses of the uncertainties frequently concluded that treatment of these is important for the reliability of the results, and neglecting this could lead to misleading conclusions. [ABSTRACT FROM AUTHOR]
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- 2023
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15. Chatbot-Based Android Application Towards Security Using FCM
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Singh, Priya, Krishnamurthi, Rajalakshmi, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Roy, Nihar Ranjan, editor, Tanwar, Sudeep, editor, and Batra, Usha, editor
- Published
- 2024
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16. Evaluation of extreme precipitation over Southeast Asia in the Coupled Model Intercomparison Project Phase 5 regional climate model results and HighResMIP global climate models.
- Author
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Hariadi, Mugni Hadi, van der Schrier, Gerard, Steeneveld, Gert‐Jan, Ratri, Dian Nur, Sopaheluwakan, Ardhasena, Tank, Albert Klein, Aldrian, Edvin, Gunawan, Dodo, Moine, Marie‐Pierre, Bellucci, Alessio, Senan, Retish, Tourigny, Etienne, Putrasahan, Dian Ariyani, and Linarka, Utoyo Ajie
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CLIMATE change models ,ATMOSPHERIC models ,RAINFALL ,CLIMATE extremes ,TROPICAL cyclones ,SPATIAL resolution - Abstract
Modelling rainfall extremes and dry periods over the Southeast Asia (SEA) region is challenging due to the characteristics of the region, which consists of the Maritime Continent and a mountainous region; it also experiences monsoonal conditions, as it is located between the Asian summer monsoon and the Australian summer monsoon. Representing rainfall extremes is important for flood and drought assessments in the region. This paper evaluates extreme rainfall climatic indices from regional climate models from CORDEX Southeast Asia and compares them with the results of high‐resolution global climate models with a comparable spatial resolution from the HighResMIP experiment. Observations indicate a high intensity of rainfall over areas affected by tropical cyclones and long consecutive dry day periods over some areas in Indochina and the southern end of Indonesia. In the model simulations, we find that both coupled and sea surface temperature‐forced HighResMIP model experiments are more similar to the observations than CORDEX model results. However, the models produce a poorer simulation of precipitation intensity‐related indices due to model biases in the rainfall intensity. This bias is higher in CORDEX than in HighResMIP and is evident in both the low‐ and high‐resolution HighResMIP model versions. The comparable performances of HighResSST (atmosphere‐only runs) and Hist‐1950 (coupled ocean–atmosphere runs) demonstrate the accuracy of the ocean model. Comparable performances were also found for the two different resolutions of HighResMIP, suggesting that there is no improvement in the performance of the high‐resolution HighResMIP model compared to the low‐resolution HighResMIP model. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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17. Skill and Intercomparison of Global Climate Models in Simulating Wind Speed, and Future Changes in Wind Speed over South Asian Domain.
- Author
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Lakku, Naresh K. G. and Behera, Manasa R.
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WIND speed ,ATMOSPHERIC models ,COASTAL plains ,WIND power ,POTENTIAL energy - Abstract
Investigating the role of complex dynamical components of a global climate model (GCM) in improving near-surface wind speed (WS) simulation is vital for the climate community in building reliable future WS projections. The relative skill of GCMs in representing WS at diverse climate variable scales (daily, monthly, seasonal, and annual) over land and ocean areas of the South Asian domain is not clear yet. With this in mind, this paper evaluated the skill of 28 Coupled Model Intercomparison Project phase five GCMs in reproducing the WS using a devised relative score approach. It is recommended to use the mean ensemble of MPI-ESM-MR, CSIRO-Mk3.6.0, and GFDL-ESM2G GCMs for understanding future changes in wind–wave climate and offshore wind energy potential. The inter-comparison of GCMs shows that the GCM with high or low atmospheric resolution does not necessarily exhibit the best or worst performance, respectively, whereas the dynamic components in the model configuration play the major role, especially the atmosphere component relative to other dynamical components. The strengthening of annual and seasonal mean WS is observed over coastal plains of the United Republic of Tanzania, Oman, eastern Thailand, eastern Gulf of Thailand and Sumatra, and weakening over the central northern equatorial region of the Indian Ocean in the 21st century for RCP4.5 and RCP8.5 emission scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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18. An Efficient HW/SW Design for Text Extraction from Complex Color Image .
- Author
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Ben Atitallah, Mohamed Amin, Kachouri, Rostom, Atitallah, Ahmed Ben, and Mnif, Hassene
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PEOPLE with visual disabilities ,INTELLECTUAL property ,COLOR ,COPROCESSORS - Abstract
In the context of constructing an embedded system to help visually impaired people to interpret text, in this paper, an efficient High-level synthesis (HLS) Hardware/Software (HW/SW) design for text extraction using the Gamma Correction Method (GCM) is proposed. Indeed, the GCM is a common method used to extract text from a complex color image and video. The purpose of this work is to study the complexity of the GCM method on Xilinx ZCU102 FPGA board and to propose a HW implementation as Intellectual Property (IP) block of the critical blocks in this method using HLS flow with taking account the quality of the text extraction. This IP is integrated and connected to the ARM Cortex-A53 as coprocessor in HW/SW codesign context. The experimental results show that the HLS HW/SW implementation of the GCM method on ZCU102 FPGA board allows a reduction in processing time by about 89% compared to the SW implementation. This result is given for the same potency and strength of SW implementation for the text extraction. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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19. Near surface ocean temperature uncertainty related to initial condition uncertainty.
- Author
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Tokmakian, Robin and Challenor, Peter
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SURFACE temperature ,OCEAN temperature ,UNCERTAINTY ,GREENHOUSE gases ,SPACETIME ,ATMOSPHERIC models - Abstract
Contributions to climate uncertainty in the modeling of the near surface temperature of the ocean come from several sources: the knowledge of the initial state of the atmosphere, the inadequacy of a model to include or correctly represent all aspects of the dynamics, the uncertain knowledge of the initial state of the ocean and small-scale (or internal, "weather") noise. This paper concentrates on the latter uncertainty, the uncertainty in the knowledge of the initial field, resulting in a map of the uncertainty of the near surface temperature field. To make the full estimate of this uncertainty, the outcomes from a relatively small, 30 member, ensemble were expanded using statistical emulators. The uncertainty varies in space and decreases in time. There are broad areas of similar uncertainty, consistent with uncertainties in the initial conditions and the variability in local processes. After 10 years, the average spatial uncertainty calculated from this expanded data set gives a range of +/− 0.4 ∘ C with 95% of the spatial areas having an uncertainty of less than +/− 0.9 ∘ C. When compared to other estimates of similar metrics, the map represents a lower bound on the uncertainty because this first experiment examines the ocean/ice system in isolation from feedbacks that occur between the atmosphere and the ocean. This uncertainty also does not include any contribution from the lack of knowledge about how a future state of the air/ocean system will be forced by changes in greenhouse gases. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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20. Future Climate of Colombo Downscaled with SDSM-Neural Network.
- Author
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Singay Dorji, Herath, Srikantha, and Mishra, Binaya Kumar
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ATMOSPHERIC models ,ARTIFICIAL neural networks ,DOWNSCALING (Climatology) ,STANDARD deviations ,CLIMATE change - Abstract
The Global Climate Model (GCM) run at a coarse spatial resolution cannot be directly used for climate impact studies. Downscaling is required to extract the sub-grid and local scale information. This paper investigates if the artificial neural network (ANN) is better than the widely-used regression-based statistical downscaling model (SDSM) for downscaling climate for a site in Colombo, Sri Lanka. Based on seasonal and annual model biases and the root mean squared error (RMSE), the ANN performed better than the SDSM for precipitation. This paper proposes a novel methodology for improving climate predictions by combining SDSM with neural networks. This method will allow a user to apply SDSM with a neural network model for higher skills in downscaling. The study uses the Canadian Earth System Model (CanESM2) of the IPCC Fifth Assessment Report, reanalysis from the National Center for Environmental Prediction (NCEP), and the Asian Precipitation Highly Resolved Observational Data Integration towards Evaluation of Water Resources (APHRODITE) project data as the observation. SDSM and the focused time-delayed neural network (TDNN) models are used for the downscaling. The projected annual increase for Representative Concentration Pathway (RCP) is 8.5; the average temperature is 2.83 °C (SDSM) and 3.03 °C (TDNN), and rainfall is 33% (SDSM) and 63% (TDNN) for 2080's. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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21. Climate Change Impact Assessment on Water Resources–A Review
- Author
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Surkar, Prajakta Prabhakar, Choudhary, M. K., di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Timbadiya, P. V., editor, Singh, Vijay P., editor, and Sharma, Priyank J., editor
- Published
- 2023
- Full Text
- View/download PDF
22. LEA Detection and Tracking Method for Color-Independent Visual-MIMO.
- Author
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Jai-Eun Kim, Ji-Won Kim, and Ki-Doo Kim
- Abstract
Communication performance in the color-independent visual-multiple input multiple output (visual-MIMO) technique is deteriorated by light emitting array (LEA) detection and tracking errors in the received image because the image sensor included in the camera must be used as the receiver in the visual-MIMO system. In this paper, in order to improve detection reliability, we first set up the color-space-based region of interest (ROI) in which an LEA is likely to be placed, and then use the Harris corner detection method. Next, we use Kalman filtering for robust tracking by predicting the most probable location of the LEA when the relative position between the camera and the LEA varies. In the last step of our proposed method, the perspective projection is used to correct the distorted image, which can improve the symbol decision accuracy. Finally, through numerical simulation, we show the possibility of robust detection and tracking of the LEA, which results in a symbol error rate (SER) performance improvement. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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23. Amplified drying in South Asian summer monsoon precipitation due to anthropogenic sulfate aerosols.
- Author
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Fadnavis, Suvarna, Asutosh, A., Chavan, Prashant, Thaware, Rakshit, and Tilmes, Simone
- Subjects
SULFATE aerosols ,EL Nino ,LA Nina ,MONSOONS ,SUMMER ,RAINFALL ,OZONE - Abstract
A declining trend in Indian summer monsoon precipitation (ISMP) in the latter half of the 20th century is a scientifically challenging and societally relevant research issue. Heavy aerosol loading over India is one of the key factors in modulating the ISMP. Using the state-of-the-state-of-the-art chemistry-climate model, ECHAM6-HAMMOZ, the impacts of South Asian anthropogenic sulfate aerosols on the Indian summer monsoon precipitation were investigated against: (1) 2010 La Niña (excess monsoon), (2) 2015 El Niño (deficit monsoon) in comparison to (3) normal monsoon 2016. Sensitivity simulations were designed with 48% enhancement in South Asian SO 2 emissions based on a trend estimated from Ozone Monitoring Instrument (OMI) satellite observations during 2006–2017. The model simulations showed that sulfate aerosols reduce ISMP by 27.5%–43.3 %, while simulations without sulfate loading enhanced ISMP by 23% in 2010 La Niña and reduction by 35% in 2015 El Niño. This paper reports that sulfate aerosols loading over India reduce precipitation by aerosol-induced direct and indirect effects by inducing atmospheric cooling, weakening in the convection, and reduction in moisture transport to Indian landmass. This paper emphasizes the necessity of alternate use of energy to reduce sulfate aerosol emissions to solve water issues in South Asia. [Display omitted] • Sulfate emission reduces Indian summer monsoon precipitation through aerosol-radiation and aerosol-cloud interactions. • Over 27% of the summer monsoon rainfall deficit in a normal year are linked to Asian anthropogenic sulfate emissions. • Sulfate-induced rainfall reduction is the maximum for La Niña year. • SO 2 loading increases atmospheric stability and weakens moisture transport to India. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Refining projected multidecadal hydroclimate uncertainty in East-Central Europe using CMIP5 and single-model large ensemble simulations
- Author
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Topál, Dániel, Hatvani, István Gábor, and Kern, Zoltán
- Published
- 2020
- Full Text
- View/download PDF
25. Uncertainty in modeled upper ocean heat content change.
- Author
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Tokmakian, Robin and Challenor, Peter
- Subjects
CLIMATE change ,ENTHALPY ,ATMOSPHERIC models ,GENERAL circulation model ,DISTRIBUTION (Probability theory) ,OCEAN circulation - Abstract
This paper examines the uncertainty in the change in the heat content in the ocean component of a general circulation model. We describe the design and implementation of our statistical methodology. Using an ensemble of model runs and an emulator, we produce an estimate of the full probability distribution function (PDF) for the change in upper ocean heat in an Atmosphere/Ocean General Circulation Model, the Community Climate System Model v. 3, across a multi-dimensional input space. We show how the emulator of the GCM's heat content change and hence, the PDF, can be validated and how implausible outcomes from the emulator can be identified when compared to observational estimates of the metric. In addition, the paper describes how the emulator outcomes and related uncertainty information might inform estimates of the same metric from a multi-model Coupled Model Intercomparison Project phase 3 ensemble. We illustrate how to (1) construct an ensemble based on experiment design methods, (2) construct and evaluate an emulator for a particular metric of a complex model, (3) validate the emulator using observational estimates and explore the input space with respect to implausible outcomes and (4) contribute to the understanding of uncertainties within a multi-model ensemble. Finally, we estimate the most likely value for heat content change and its uncertainty for the model, with respect to both observations and the uncertainty in the value for the input parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
26. A multimodel assessment of drought characteristics and risks over the Huang-Huai-Hai River basin, China, under climate change
- Author
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Dai, C., Qin, X. S., Lu, W. T., and Zang, H. K.
- Published
- 2020
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27. West African monsoon decadal variability and surface-related forcings: second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II).
- Author
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Xue, Yongkang, Sales, Fernando, Lau, William, Boone, Aaron, Kim, Kyu-Myong, Mechoso, Carlos, Wang, Guiling, Kucharski, Fred, Schiro, Kathleen, Hosaka, Masahiro, Li, Suosuo, Druyan, Leonard, Sanda, Ibrah, Thiaw, Wassila, Zeng, Ning, Comer, Ruth, Lim, Young-Kwon, Mahanama, Sarith, Song, Guoqiong, and Gu, Yu
- Subjects
CLIMATE change ,WEST African monsoons ,CLIMATOLOGY ,CLIMATE change mathematical models ,DROUGHTS ,METEOROLOGICAL precipitation - Abstract
The second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II) is designed to improve understanding of the possible roles and feedbacks of sea surface temperature (SST), land use land cover change (LULCC), and aerosols forcings in the Sahel climate system at seasonal to decadal scales. The project's strategy is to apply prescribed observationally based anomaly forcing, i.e., 'idealized but realistic' forcing, in simulations by climate models. The goal is to assess these forcings' effects in producing/amplifying seasonal and decadal climate variability in the Sahel between the 1950s and the 1980s, which is selected to characterize the great drought period of the last century. This is the first multi-model experiment specifically designed to simultaneously evaluate such relative contributions. The WAMME II models have consistently demonstrated that SST forcing is a major contributor to the twentieth century Sahel drought. Under the influence of the maximum possible SST forcing, the ensemble mean of WAMME II models can produce up to 60 % of the precipitation difference during the period. The present paper also addresses the role of SSTs in triggering and maintaining the Sahel drought. In this regard, the consensus of WAMME II models is that both Indian and Pacific Ocean SSTs greatly contributed to the drought, with the former producing an anomalous displacement of the Intertropical Convergence Zone before the WAM onset, and the latter mainly contributes to the summer WAM drought. The WAMME II models also show that the impact of LULCC forcing on the Sahel climate system is weaker than that of SST forcing, but still of first order magnitude. According to the results, under LULCC forcing the ensemble mean of WAMME II models can produces about 40 % of the precipitation difference between the 1980s and the 1950s. The role of land surface processes in responding to and amplifying the drought is also identified. The results suggest that catastrophic consequences are likely to occur in the regional Sahel climate when SST anomalies in individual ocean basins and in land conditions combine synergistically to favor drought. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. Assessing the impact of climate change over the northwest of Iran: an overview of statistical downscaling methods.
- Author
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Baghanam, Aida Hosseini, Eslahi, Mehdi, Sheikhbabaei, Ali, and Seifi, Arshia Jedary
- Subjects
DOWNSCALING (Climatology) ,CLIMATE change ,STANDARD deviations ,RANK correlation (Statistics) ,ARTIFICIAL neural networks - Abstract
Due to the spatial-temporal inadequacy of large-scale general circulation models (GCMs), linking large-scale GCM data with small-scale local climatic data has found great interest. In this paper, in order to downscale minimum and maximum temperatures and precipitation predictands, the performance of three statistical downscaling techniques including Long Ashton Research Station-Weather Generator (LARS-WG), statistical downscaling model (SDSM), and artificial neural network (ANN) was compared based on Intergovernmental Panel on Climate Change-Fifth Assessment Report (IPCC-AR5) in northwest Iran. For this purpose, a nonparametric test named Mann-Whitney test, Spearman correlation coefficient, and the root mean square error (RMSE) were utilized to assess the efficiency of downscaling models. To scrutinize the climate change impacts, periods of 1961–1990 and 1991–2005 were considered as the baseline and verification periods, respectively. The findings revealed the superior performance of the ANN model for minimum and maximum temperatures, while for precipitation predictand, the SDSM represented the best performance among the models. Simulation results for future temperature indicated an ascending trend as 0.1–1.3 °C, 0.3–1.7 °C, and 0.5–2.1 °C for LARS-WG, SDSM, and ANN techniques, respectively. On the other hand, simulation outputs for the precipitation indicated a descending trend of 10–30% in future precipitation of the region according to downscaling models under Representative Concentration Pathway 8.5 (RCP8.5) pessimistic scenario of Hadley Center Coupled Model version 3 (HadCM3) GCM model. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
29. Skill and uncertainty in surface wind fields from general circulation models: Intercomparison of bias between AGCM, AOGCM and ESM global simulations.
- Author
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Morim, Joao, Hemer, Mark, Andutta, Fernando, Shimura, Tomoya, and Cartwright, Nick
- Subjects
GENERAL circulation model ,OCEAN temperature ,ATMOSPHERIC physics ,ABILITY ,UNCERTAINTY ,ATMOSPHERIC models - Abstract
Understanding the reliability of global climate models (GCMs) to reproduce the historical surface wind fields is integral part of building robust projections of surface wind‐climate, and other wind‐dependent geophysical climatic variables. Understanding the skill of atmosphere‐only models (AGCM), coupled atmosphere–ocean models (AOGCM) and fully coupled earth system models (ESM) is likewise paramount to assess any systematic model improvements. In this paper, we systematically assess whether surface wind fields obtained from 28 CMIP5 GCMs can represent large‐scale spatial patterns and temporal variability of historical surface winds. We show that inter‐model uncertainty is typically 2–4 times larger than the uncertainty associated with GCM internal variability, although the latter can be significant within specific regions. We also find that CMIP5 models are typically capable of reliably reproducing large‐scale spatial patterns of historical near‐surface winds, but considerable uncertainty lies within the CMIP5 ensemble with strong latitudinal dependence. CMIP5 models show limitations in their ability to reliably represent inter‐annual and inter‐seasonal variability particularly within tropical‐cyclone‐affected regions. In further analysis, we quantify and intercompare historical wind bias from different types of models with different dynamical cores, based on multiple CMIP5 diagnostic experiments. We find that bias in surface wind fields are largely intrinsic to the atmospheric components of the models, and that the inclusion of carbon‐cycle dynamics has insignificant effect on simulated surface winds (at decadal time‐scales). Inconsistencies between AGCM and AOGCM simulations are largely driven by errors in sea surface temperatures (SST); though such differences are not statistically significant relative to the inter‐model uncertainty within the CMIP5 ensemble. These results show that the dominant source of bias in simulated wind fields lies in the underlying physics of the atmospheric component of the models. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. How well do climate models reproduce variability in observed rainfall? A case study of the Lake Victoria basin considering CMIP3, CMIP5 and CORDEX simulations
- Author
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Onyutha, Charles, Rutkowska, Agnieszka, Nyeko-Ogiramoi, Paul, and Willems, Patrick
- Published
- 2019
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31. Enhancing Monsoon Predictions for the Upper Chambal Catchment Through Temporal and Spatial Downscaling of Predicted Future Precipitation
- Author
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Bagora, Poonam and Narulkar, Sandeep
- Published
- 2024
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- View/download PDF
32. Comparative analysis of bias correction techniques for future climate assessment using CMIP6 hydrological variables for the Indian subcontinent
- Author
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Shah, Meghal, Thakkar, Amit, and Shastri, Hiteshri
- Published
- 2024
- Full Text
- View/download PDF
33. Contemporary GCM Fidelity in Representing the Diurnal Cycle of Precipitation Over the Maritime Continent.
- Author
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Baranowski, Dariusz B., Waliser, Duane E., Jiang, Xianan, Ridout, James A., and Flatau, Maria K.
- Subjects
DIURNAL variations in meteorology ,METEOROLOGICAL precipitation ,OCEAN-atmosphere interaction ,OSCILLATIONS ,RAINFALL anomalies - Abstract
This paper presents a multimodel assessment of fidelity in representation of the diurnal cycle of precipitation over the Maritime Continent (MC). Daily mean precipitation rate and amplitude and phase of the diurnal cycle are utilized to validate General Circulation Model (GCM) performance with respect to multiyear annual mean and seasonal cycle. The analysis shows that models' 6‐hourly temporal resolution and 2.5° spatial resolution is sufficient to depict key characteristic of diurnal precipitation. Results show that most models are sensitive to the existence of the MC and show different characteristics of subdaily precipitation. However, 19 out of 20 models underestimate the daily mean precipitation over the eastern Indian Ocean and most of them underestimate both daily mean precipitation and amplitude of the diurnal cycle, especially over islands within the region. Observations show that within the MC the diurnal cycle is higher over land than over ocean. Many models decrease this land‐sea contrast. Most models recognize difference in phase of the diurnal cycle between MC islands and surrounding ocean, but some of them show opposite phasing of the diurnal cycle. Results show that modern models perform better than past generation, sometimes comparably to regional models' run in much higher resolution. Although models perform well with respect to the seasonal cycle of the daily mean precipitation, they fail to realistically represent the seasonal evolution of the diurnal cycle amplitude. Additionally, models show no coherence in land‐ocean contrast derived from a multiyear average of daily mean precipitation and amplitude of the diurnal cycle. Key Points: GCMs are sensitive to the existence of the Maritime Continent in the Indo‐Pacific warm poolMost models underestimate daily mean precipitation and amplitude of the diurnal cycle, especially over landMost GCMs underestimate land‐sea contrast in precipitation characteristics [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
34. Accounting for Vertical Subgrid‐Scale Heterogeneity in Low‐Level Cloud Fraction Parameterizations.
- Author
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Jouhaud, J., Dufresne, J.‐L., Madeleine, J.‐B., Hourdin, F., Jam, A., Couvreux, F., and Villefranque, N.
- Subjects
GENERAL circulation model ,PROBABILITY density function ,ATMOSPHERIC models ,ATMOSPHERIC boundary layer ,ATMOSPHERIC water vapor ,CUMULUS clouds - Abstract
Many general circulation models (GCMs) assume some heterogeneity of water amounts in their grid boxes and use probability density functions to parameterize cloud fractions CF and amounts of condensed water qc. Most GCM cloud schemes calculate the CF as the volume of the grid box that contains clouds (CFvol), whereas radiative fluxes primarily depend on the CF by surface (CFsurf), that is, the surface of the grid box covered by clouds when looking from above. This discrepancy matters as previous findings suggest that CFsurf is typically greater than CFvol by about 30%. In this paper we modify the single column model version of the LMDz GCM cloud scheme by introducing the vertical subgrid‐scale heterogeneity of water content. This allows to distinctly compute the two fractions, CFvol and CFsurf, as well as the amount of condensed water qc. This study is one of the first to take into account such vertical subgrid‐scale heterogeneity in a GCM cloud scheme. Three large eddy simulation cases of cumuliform boundary layer clouds are used to test and calibrate two different parameterizations. These new developments increase cloud cover by about 10% for the oceanic cases RICO and Barbados Oceanographic Meteorological Experiment and by up to 50% for the continental case ARM. The change in condensed water reduces the liquid water path by 10–20% and therefore the cloud opacity by 5–50%. These results show the potential of the new scheme to reduce the too few, too bright bias by increasing low‐level CF and decreasing cloud reflectance. Key Points: Most cloud schemes assume vertically homogeneous cloud fractions in GCM grid boxesThis approximation may induce an underestimation of cloud cover and overestimation of reflectanceWe parameterize 3‐D subgrid‐scale heterogeneities for low‐level clouds and reduce these biases [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
35. On Internal Re-keying
- Author
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Akhmetzyanova, Liliya, Alekseev, Evgeny, Smyshlyaev, Stanislav, Oshkin, Igor, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, van der Merwe, Thyla, editor, Mitchell, Chris, editor, and Mehrnezhad, Maryam, editor
- Published
- 2020
- Full Text
- View/download PDF
36. A Security Framework for NoC Using Authenticated Encryption and Session Keys.
- Author
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Kapoor, Hemangee, Rao, G., Arshi, Sharique, and Trivedi, Gaurav
- Subjects
DATA encryption ,BANDWIDTHS ,EMULATION software ,NETWORKS on a chip ,SYSTEMS on a chip ,DATA protection - Abstract
Network on Chip (NoC) is an emerging solution to the existing scalability problems with System on Chip (SoC). However, it is exposed to security threats like extraction of secret information from IP cores. In this paper we present an Authenticated Encryption (AE)-based security framework for NoC based systems. The security framework resides in Network Interface (NI) of every IP core allowing secure communication among such IP cores. The secure cores can communicate using permanent keys whereas temporary session keys are used for communication between secure and non-secure cores. A traffic limiting counter is used to prevent bandwidth denial and access rights table avoids unauthorized memory accesses. We simulated and implemented our framework using Verilog/VHDL modules on top of NoCem emulator. The results showed tolerable area overhead and did not affect the network performance apart from some initial latency. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
37. Pushing AES-256-GCM to Limits: Design, Implementation and Real FPGA Tests
- Author
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Cibik, Peter, Dobias, Patrik, Ricci, Sara, Hajny, Jan, Malina, Lukas, Jedlicka, Petr, Smekal, David, Goos, Gerhard, Series Editor, Hartmanis, Juris, Founding Editor, van Leeuwen, Jan, Series Editor, Hutchison, David, Editorial Board Member, Kanade, Takeo, Editorial Board Member, Kittler, Josef, Editorial Board Member, Kleinberg, Jon M., Editorial Board Member, Kobsa, Alfred, Series Editor, Mattern, Friedemann, Editorial Board Member, Mitchell, John C., Editorial Board Member, Naor, Moni, Editorial Board Member, Nierstrasz, Oscar, Series Editor, Pandu Rangan, C., Editorial Board Member, Sudan, Madhu, Series Editor, Terzopoulos, Demetri, Editorial Board Member, Tygar, Doug, Editorial Board Member, Weikum, Gerhard, Series Editor, Vardi, Moshe Y, Series Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, and Andreoni, Martin, editor
- Published
- 2024
- Full Text
- View/download PDF
38. Ranking of CMIP 6 climate models in simulating precipitation over India
- Author
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Vinod, Degavath and Agilan, V.
- Published
- 2024
- Full Text
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39. EnOI‐IAU Initialization Scheme Designed for Decadal Climate Prediction System IAP‐DecPreS.
- Author
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Wu, Bo, Zhou, Tianjun, and Zheng, Fei
- Subjects
CLIMATE change ,OCEAN temperature ,ATLANTIC multidecadal oscillation ,PRECIPITATION anomalies ,PREDICTION models - Abstract
Abstract: A decadal climate prediction system named as IAP‐DecPreS was constructed in the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, based on a fully coupled model FGOALS‐s2 and a newly developed initialization scheme, referred to as EnOI‐IAU. In this paper, we introduce the design of the EnOI‐IAU scheme, assess the accuracies of initialization integrations using the EnOI‐IAU and preliminarily evaluate hindcast skill of the IAP‐DecPreS. The EnOI‐IAU scheme integrates two conventional assimilation approaches, ensemble optimal interpolation (EnOI) and incremental analysis update (IAU). The EnOI and IAU were applied to calculate analysis increments and incorporate them into the model, respectively. Three continuous initialization (INIT) runs were conducted for the period of 1950–2015, in which observational sea surface temperature (SST) from the HadISST1.1 and subsurface ocean temperature profiles from the EN4.1.1 data set were assimilated. Then nine‐member 10 year long hindcast runs initiated from the INIT runs were conducted for each year in the period of 1960–2005. The accuracies of the INIT runs are evaluated from the following three aspects: upper 700 m ocean temperature, temporal evolution of SST anomalies, and dominant interdecadal variability modes, Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO). Finally, preliminary evaluation of the ensemble mean of the hindcast runs suggests that the IAP‐DecPreS has skill in the prediction of the PDO‐related SST anomalies in the midlatitude North Pacific and AMO‐related SST anomalies in the tropical North Atlantic. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
40. Future Climate Change Impacts on Rice in Uttar Pradesh, India's Most Populous Agrarian State.
- Author
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Singh, Jyoti, Sahany, Sandeep, Singh, K. K., Robock, Alan, and Xia, Lili
- Subjects
WATER efficiency ,RICE ,CROP management ,DRY farming ,RAINFALL ,ATMOSPHERIC models ,CLIMATE change ,RICE farming - Abstract
Uttar Pradesh, with a population of 237 million, is the largest agrarian state in India, located in the Indo‐Gangetic plains. Rice cultivation is widespread across all districts of Uttar Pradesh, which have varying climate regimes, irrigation infrastructures, crop management practices, and farm sizes. The state is characterized by different agroecological zones (AEZs) with semi‐arid to sub‐humid climates with significant variability in monsoon rainfall. In this study, the impact of climate change on Kharif‐season rice is estimated using crop‐climate scenarios in Uttar Pradesh. A process‐based Crop Simulation Model, Crop Estimation through Resource and Environment Synthesis‐Rice, was simulated with bias‐corrected and downscaled climate data for historical (1995–2014) and three future periods (the 2030s, 2050s, and 2090s) for two mitigation pathways (SSP2‐4.5 and SSP5‐8.5) from the Coupled Model Intercomparison Project 6. Phenology, irrigation amount, crop evapotranspiration, yield, and water use efficiency were evaluated and assessed for all AEZs. Based on the ensemble of 16 climate models, rainfed rice yield increased in the AEZs of western Uttar Pradesh due to increased rainfall, while in eastern Uttar Pradesh yield decreased, under both shared socioeconomic pathways (SSPs). Irrigated rice yield decreased in all AEZs under both SSPs due to an increase in temperature and a decrease in the length of the growing period, with reductions of up to 20% by the 2090s. Irrigation requirements decreased from the 2030s to the 2090s due to increased rainfall and decreased crop evapotranspiration. Despite the projected increase in rainfed yield, the overall rice yield is expected to decrease in the future under both SSPs. Plain Language Summary: Uttar Pradesh is the most populated state in India, with most of the population working in the agriculture sector and having a low income. The state's vulnerability to climate change is high due to inadequate infrastructure and heavy dependence on agriculture. Rice is a crucial crop for the state, but this study shows that climate change will decrease rice yields in the future, especially for irrigated rice, due to higher temperatures and shorter growing seasons. While rainfed rice yields may increase in some regions due to increased rainfall, rice production is expected to decline overall. Key Points: Rice yield (combining irrigated and rainfed) in Uttar Pradesh, India, is projected to decrease in the future for SSP2‐4.5 and SSP5‐8.5With a projected increase in rainfall, rainfed rice yield increases in rainfall deficit zones, and irrigation decreases under both shared socioeconomic pathwaysPlanting in the early season could reduce the amount of yield loss for irrigated rice [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Hydrological Drought and Flood Projection in the Upper Heihe River Basin Based on a Multi-GCM Ensemble and the Optimal GCM.
- Author
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Li, Zhanling, Ye, Yingtao, Lv, Xiaoyu, Bai, Miao, and Li, Zhanjie
- Subjects
WATERSHEDS ,DROUGHTS ,TOPSIS method ,WATER security ,FLOODS ,WATER use - Abstract
To ensure water use and water resource security along "the Belt and Road", the runoff and hydrological droughts and floods under future climate change conditions in the upper Heihe River Basin were projected in this study, based on the observed meteorological and runoff data from 1987 to 2014, and data from 10 GCMs from 1987 to 2014 and from 2026 to 2100, using the SWAT model, the Standardized Runoff Index, run length theory, and the entropy-weighted TOPSIS method. Both the multi-GCM ensemble (MME) and the optimal model were used to assess future hydrological drought and flood responses to climate change. The results showed that (1) the future multi-year average runoff from the MME was projected to be close to the historical period under the SSP245 scenario and to increase by 2.3% under the SSP585 scenario, and those from the optimal model CMCC-ESM2 were projected to decrease under both scenarios; (2) both the MME and the optimal model showed that drought duration and flood intensity in the future were projected to decrease, while drought intensity, drought peak, flood duration, and flood peak were projected to increase under both scenarios in their multi-year average levels; (3) drought duration was projected to decrease most after 2080, and drought intensity, flood duration, and flood peak were projected to increase most after 2080, according to the MME. The MME and the optimal model reached a consensus on the sign of hydrological extreme characteristic responses to climate change, but showed differences in the magnitude of trends. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Deformation and Strength of Unsaturated Loess—Hydraulic Coupling Effects under Loads.
- Author
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Chai, Hao, Li, Xi'an, Qin, Biao, Wang, Weiping, and Axel, Mani
- Subjects
HYDRAULIC couplings ,LOESS ,COMPRESSION loads ,STRAINS & stresses (Mechanics) ,COMPRESSIBILITY - Abstract
The volumetric change in unsaturated loess during loading causes serious damage to the foundation and structure, accompanied by changes in hydraulic conditions. Therefore, quantifying the change in the load effect of loess under hydraulic coupling is of great significance for revealing the mechanism of hydraulic interaction. This study conducts isotropic compression and undrained shear tests on unsaturated compacted loess, simultaneously introducing the strength parameter η to enhance the Glasgow coupled model (GCM). The objective is to elucidate the hydraulic and mechanical coupling mechanism, where saturation increases under mechanical effects lead to strength degradation. The results show that saturation increases under mechanical effects improve the compressibility of the sample, and saturation has a direct impact on the stress–strain relationship. The increase in water content and confining pressure increases the trend of the critical state stress ratio M decreasing, and the strain softening trend increases. The compression of volume during shear tests increases the saturation, changes the hydraulic characteristics of loess, and affects the deformation and strength of loess. The modified GCM improves the applicability and prediction accuracy of unsaturated loess under the same initial state. The research results are of great significance for revealing the hydraulic and mechanical behavior of loess. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Interoperability Evaluation Case Study: An Obstetrics-Gynecology Department and Related Information Systems.
- Author
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Vida, Mihaela, Stoicu-Tivadar, Lăcrămioara, Blobel, Bernd, and Bernad, Elena
- Abstract
The paper presents the steps and metrics for evaluating the interoperability of an Obstetrics-Gynecology Department Information System applied on Bega Clinic Timisoara regarding its readiness for interoperability in relation with similar systems. The developed OGD IS was modeled starting from the Generic Component Model and sends information to other medical units using the HL7 Clinical Document Architecture and Continuity of Care Document standards. The data for evaluation are real, collected between 2009 and 2010 from Bega Clinic Timisoara. The results were relatively good for the investigated data and structure. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
44. Integrating plant–soil interactions into global carbon cycle models.
- Author
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Ostle, Nicholas J., Smith, Pete, Fisher, Rosie, Woodward, F. Ian, Fisher, Joshua B., Smith, Jo U., Galbraith, David, Levy, Peter, Meir, Patrick, McNamara, Niall P., and Bardgett, Richard D.
- Subjects
PLANT-soil relationships ,CARBON cycle ,BIOGEOCHEMISTRY ,GLOBAL environmental change ,CLIMATE change ,NITROGEN ,ENVIRONMENTAL sciences - Abstract
1. Plant–soil interactions play a central role in the biogeochemical carbon (C), nitrogen (N) and hydrological cycles. In the context of global environmental change, they are important both in modulating the impact of climate change and in regulating the feedback of greenhouse gas emissions (CO
2 , CH4 and N2 O) to the climate system. 2. Dynamic global vegetation models (DGVMs) represent the most advanced tools available to predict the impacts of global change on terrestrial ecosystem functions and to examine their feedbacks to climate change. The accurate representation of plant–soil interactions in these models is crucial to improving predictions of the effects of climate change on a global scale. 3. In this paper, we describe the general structure of DGVMs that use plant functional types (PFTs) classifications as a means to integrate plant–soil interactions and illustrate how models have been developed to improve the simulation of: (a) soil carbon dynamics, (b) nitrogen cycling, (c) drought impacts and (d) vegetation dynamics. For each of these, we discuss some recent advances and identify knowledge gaps. 4. We identify three ongoing challenges, requiring collaboration between the global modelling community and process ecologists. First, the need for a critical evaluation of the representation of plant–soil processes in global models; second, the need to supply and integrate knowledge into global models; third, the testing of global model simulations against large-scale multifactor experiments and data from observatory gradients. 5. Synthesis. This paper reviews how plant–soil interactions are represented in DGVMs that use PFTs and illustrates some model developments. We also identify areas of ecological understanding and experimentation needed to reduce uncertainty in future carbon coupled climate change predictions. [ABSTRACT FROM AUTHOR]- Published
- 2009
- Full Text
- View/download PDF
45. Scattering ice clouds
- Author
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Smith, Helen, Webb, Ann, and Connolly, Paul
- Subjects
551.57 ,linear depolarization ratio ,asymmetry parameter ,GCM ,scattering ,ice crystal ,ray tracing - Abstract
The 2013 meeting of the Intergovernmental Panel on Climate Change concluded that the coupling of clouds to the Earth's climate is one of the biggest uncertainties faced in predicting climate change today. Cirrus clouds are of particular interest because the extensive variability in particle size, shape and complexity poses a number of challenges in the accurate modelling of optical properties. The dependence of the single-scattering properties on particle shape demand accurate representation of the crystal geometries in scattering models, geometries which can vary from simple hexagonal prisms to complex multi-branched aggregates. This work, presented as a series of papers, uses laboratory studies to investigate the single scattering properties of ice crystals. Of particular focus here are columns with internal cavities. The first paper investigates the phase function, P11 and asymmetry parameter, g of varying crystal habits, whilst the second paper focuses on polarised scattering. One of the main findings is the difference in internal structure between hollow columns grown at warmer temperatures (-7 degrees C) and those grown at colder temperatures (-30 degrees C). Measurements were used to create new particle geometries for use in scattering models. The third paper makes use of findings from papers 1 & 2 to create an optical parametrization for cirrus, utilizing the new particle geometry.
- Published
- 2015
46. 첨단센서 제어 기반 시약장 모니터링 시스템.
- Author
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양새동, 장재명, and 정회경
- Abstract
Recently, the reagent in the laboratory can not only confirm the internal environment through the sensor but also acheck the status inside the reagent cabinet in real time. Also, if an abnormality occurs in the inside of the reagent cabinet, a serious accident may occur. To solve these problems, this paper proposes a reagent monitoring system that integrates reagent and ICT. The sensor data measured in real time is displayed to the user in real time through the monitor and stored in the database. In addition, by using the stored data, it is possible to inform the registered administrator in real time of the dangerous situation by informing the dangerous situation in case of danger, and to be able to check and control remotely. This can improve safety by making control and confirmation of the state of the inside of the reagent everywhere. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
47. Stable water isotopes of precipitation in China simulated by SWING2 models.
- Author
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Che, Yanjun, Zhang, Mingjun, Wang, Shengjie, Wang, Jie, Liu, Yangmin, and Zhang, Fuxian
- Abstract
The stable water isotope ratio in precipitation is a useful tracer of atmospheric circulation. Such observations, however, are very limited in space and time. To solve this problem, many isotope-enabled general circulation models (GCMs) are used to help the interpretation of isotope proxies. In this paper, several isotope-enabled GCMs released by the second Stable Water Isotope Intercomparison Group (SWING2) were selected to assess the spatial pattern of deuterium ( δD) and the deuterium excess ( d) of precipitation in China. The isotopic data of the Global Network of Isotopes in Precipitation (GNIP) and the Chinese Network of Isotopes in Precipitation (CHNIP) were also applied to verify the simulations. The results indicate that these models accurately simulate the spatial characteristics of δD and d of precipitation in China. The correlation between the observations and simulations for LMDZ is the highest among these models, while the root-mean-square (RMS) and standard deviation are not perfect. In addition, LMDZ is worse than other models in capturing the low signal in certain regions, such as CAM, GISS_E, and MIROC. For the monthly variation, most SWING2 models underestimate δD of the precipitation but overestimate the value of d, except for isoGSM. The simulated monthly variation of the water isotopes from SWING2 models is in general similar to the observations, and the trend corresponds to the monthly variation in the Northern Hemisphere. Moreover, all models are good at illustrating the temperature and precipitation amount effects, while they exhibit varying skills in interpreting the altitude and continental effects. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
48. Dynamical Downscaling for Climate Projection with High-Resolution MRI AGCM-RCM.
- Author
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Akio KITOH, Tomoaki OSE, and Izuru TAKAYABU
- Subjects
DOWNSCALING (Climatology) ,MAGNETIC resonance imaging ,CLIMATE change forecasts ,TOPOGRAPHY ,RAINFALL - Abstract
High-resolution downscaling is vital to project climate extremes and their future changes by resolving fine topography reasonably well, which is a key to represent local climatology and impacts of weather extremes. A direct dynamical downscaling with a regional climate model (RCM) embedded within an atmosphere-ocean coupled general circulation model (AOGCM) is commonly used but is subject to systematic biases in their present-day simulations of AOGCM, which may cause unexpected effects on future projections and lead to difficult interpretation of climate change. In a high-resolution atmospheric general circulation model (AGCM)-RCM system, the present-day climate in AGCM is forced by observed sea surface temperature (SST) and sea-ice distribution. Then, the future climate is calculated with the "future" boundary conditions (SST and sea-ice), which are created by adding their future changes projected by AOGCM to the observed present-day values, besides the future radiative forcing. This system is one of methods to minimize the effects of such biases. A Meteorological Research Institute AGCM with 20-km grids is successfully applied to project future changes in weather extremes such as tropical cyclones and rain systems that cause heavy rainfall and strong winds. Regional downscaling with 5-km mesh RCM is then performed over certain area to investigate local extreme rainfall events and their future changes. In this paper, we review various downscaling methods and try to rationalize a use of high-resolution AGCM-RCM system. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
49. Mountain Waves in the Upper Atmosphere of Venus.
- Author
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Navarro, T. and Schubert, G.
- Subjects
MOUNTAIN wave ,VENUSIAN atmosphere ,UPPER atmosphere ,THERMOSPHERE ,GENERAL circulation model ,WIND speed - Abstract
Planetary‐scale mountain waves have been observed at the cloud top of Venus and throughout the cloud deck. As they propagate from the surface to the cloud layers, multiple observations and numerical simulations have shown that they grow in size and do not break. However, the fate of mountain waves in the transition region and thermosphere, above the super‐rotating atmosphere, has only been addressed with two‐dimensional models. We conduct for the first time a simulation of mountain waves with a state‐of‐the‐art Venus climate model that includes the thermosphere. We find that mountain waves can propagate up to at least 150 km altitude, well above the transition region. They affect the circulation of the transition region, by reducing winds speeds, and the subsolar‐to‐antisolar circulation. Plain Language Summary: The planet Venus rotates very slowly, with a rotation period of 243 days, while its cloud cover rotates westwards much faster, with a period of 4 days at 70 km altitude, a phenomenon known as superrotation, which is not fully explained yet. Higher up, in the thermosphere, the air flows from the dayside to the nightside, rather than westwards. The thermosphere is difficult to explore by remote sounding due to the low air density, and thus its connection to the surface and the superrotating layer is poorly understood. In 2015, the Venus‐orbiting spacecraft Akatsuki detected a massive standing wave generated at the surface and reaching the superrotating layer, despite the fast zonal winds. Here, we show that this wave also reaches the thermosphere. Key Points: The first simulation of mountain waves with a 3D ground‐to‐thermosphere General Circulation Model is performedMountain waves reach the thermosphere of Venus and change the SS‐AS winds by up to 80 m/s, locally in the afternoonThe vertical wind field above the cloud deck is dominated by the effect of mountain waves [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Climatology of mesosphere and lower thermosphere diurnal tides over Jicamarca (12∘S, 77∘W): observations and simulations.
- Author
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Suclupe, Jose, Chau, Jorge L., Conte, J. Federico, Milla, Marco, Pedatella, N. M., and Kuyeng, K.
- Subjects
THERMOSPHERE ,CLIMATOLOGY ,MESOSPHERE ,ROSSBY waves ,ATMOSPHERIC boundary layer ,ATMOSPHERIC models - Abstract
This work shows a 3-year climatology of the horizontal components of the solar diurnal tide, obtained from wind measurements made by a multistatic specular meteor radar (SIMONe) located in Jicamarca, Peru (12 ∘ S, 77 ∘ W). Our observations show that the meridional component is more intense than the zonal component, and that it exhibits its maxima shifted with respect to the equinox times (i.e., the largest peak occurs in August–September, and the second one in April–May). The zonal component only shows a clear maximum in August–September. This observational climatology is compared to a climatology obtained with the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). Average comparisons indicate that the model amplitudes are 50% smaller than the observed ones. The WACCM-X results are also used in combination with observed altitude profiles of the tidal phases to understand the relative contributions of migrating and non-migrating components. Based on this, we infer that the migrating diurnal tide (DW1) dominates in general, but that from June until September (November until July) the DE3 (DW2) may have a significant contribution to the zonal (meridional) component. Finally, applying wavelet analysis to the complex amplitude of the total diurnal tide, modulating periods between 5 and 80 days are observed in the SIMONe measurements and the WACCM-X model. These modulations might be associated to planetary waves and intraseasonal oscillations in the lower tropical atmosphere. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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