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Precipitation predictability using the non‐scale‐aware and scale‐aware convective parameterization schemes (CPSs) was investigated to assess the necessity of the CPSs within the gray‐zone. This study evaluates the performance of the Weather Research and Forecasting (WRF) model's CPS for 135 heavy rainfall events (HREs) over the Korean Peninsula for 10 years (i.e., 2011–2020). We tested the Kain–Fritsch (KF) scheme (non‐scale‐aware) and Multi‐scale Kain–Fritsch (MSKF) scheme (scale‐aware) in the WRF model. The MSKF scheme shows an overall improved performance of precipitation simulation compared to the KF scheme, but the precipitation forecast performance of CPS depends on the characteristics of HREs. When the HREs are characterized by synoptic‐scale atmospheric conditions with strong winds and large‐scale water vapor transport, the forecast performance of both CPSs is similar because a cloud microphysics scheme can explicitly resolve most of the precipitation. However, in the case of HREs with weak synoptic forcing conditions (e.g., moisture transport and winds) related to the localized and meso‐scale HREs, the MSKF scheme can improve overall simulated precipitation by increasing grid‐scale precipitation and reducing the overestimation of subgrid‐scale precipitation simulated in the KF scheme. Therefore, using the scale‐aware CPS in the gray‐zone can provide more accurate precipitation forecasts regardless of the environmental condition of the HREs. In this study, we evaluate the predictability of precipitation using two types of convective parameterization schemes (CPS), non‐scale‐aware and scale‐aware, in the Weather Research and Forecasting (WRF) model. The scale‐aware CPS utilizes scale‐aware parameters to adjust convection processes based on horizontal resolution. We focus on heavy rainfall events (HREs) over the Korean Peninsula for 10 years from 2011 to 2020. A HRE is defined as rainfall greater than 110 mm in 12 hr. The results show that the scale‐aware CPS improved the precipitation forecast performance compared to the non‐scale‐aware CPS, and the precipitation forecast performance of CPS differs depending on the characteristics of HREs. For HREs characterized by the synoptic forcing conditions with strong winds and large‐scale horizontal advection of water vapor, both CPSs perform well, but their forecast performance decreases for HREs with weak synoptic forcing conditions. We also find that for localized heavy rain cases, using the scale‐aware CPS helps improve precipitation forecasts at 4‐km horizontal resolution. We evaluate the impacts of the non‐scale‐aware and scale‐aware convective parameterization scheme (CPS) in the gray‐zone using the Weather Research and ForecastingThe precipitation forecast performance of CPS depends on the type of heavy rainfall event (HRE) and environmental conditionsThe scale‐aware CPS in the gray‐zone can provide more accurate precipitation forecasts regardless of the environmental condition of the HREs We evaluate the impacts of the non‐scale‐aware and scale‐aware convective parameterization scheme (CPS) in the gray‐zone using the Weather Research and Forecasting The precipitation forecast performance of CPS depends on the type of heavy rainfall event (HRE) and environmental conditions The scale‐aware CPS in the gray‐zone can provide more accurate precipitation forecasts regardless of the environmental condition of the HREs

Studies have shown that regional climate models (RCMs) can simulate local climates at a higher resolution for specific regions compared to global climate models (GCMs), making dynamic downscaling using RCMs a more effective approach. Therefore, RCMs have become valuable tools for evaluating the potential impacts of climate change on specific regions and for informing local adaptation strategies. To fully understand the added value (AV) of RCMs, it is essential to understand how the characteristics differ between land and ocean. The complex topography of East Asia, including land and sea, makes it a suitable region for evaluating the AV of RCMs. In this study, we compared two regional simulations that integrated the same RCMs but employed different GCMs from the Coordinated Regional Climate Downscaling Experiment for their ability to simulate storm tracks in East Asia. The results of the RCMs for the period from 1982 to 2005 were compared with their host Coupled Model Intercomparison Project GCM projections and high‐resolution reanalysis. In mountainous regions, the AV of the RCMs weakened the bias of the GCM and improved its agreement with the reanalysis due to the dynamical process near the high‐resolution topography. In plains and coastal areas, owing to the increase in horizontal resolution and clearly determined coastline in RCMs, small‐scale phenomena are well represented, and the storm track of RCMs shows similar values to that of the GCM in maritime regions. This study demonstrates the value of RCMs for improving the accuracy of climate projections in East Asia, informing adaptation strategies, and enhancing climate research. This study looked at how regional climate models can better simulate local climates in specific regions compared to global climate models. By analyzing storm tracks in East Asia, researchers compared regional climate models integrated with different global climate models to better understand the added value of regional climate models. The study found that the regional climate models improved the accuracy of global climate models over mountainous regions and brought them closer to high‐resolution reanalysis. In the plains and coastal areas, the regional climate models accurately represented small‐scale phenomena due to the increase in horizontal resolution. Overall, this study shows that regional climate models are valuable tools for evaluating climate change in specific regions and can provide more accurate predictions than global climate models alone. This research is essential for improving our understanding of how climate models work and can be used to better predict the future climate of different regions, which can help inform decision‐making about mitigating climate change. Regional climate models improve accuracy of climate projections for East Asia by simulating local climates at higher resolution than global climate modelsRegional climate models effectively evaluate potential impacts of local climate variability on specific regions and inform local adaptation strategiesThe added value of regional climate models in improving global climate models' bias and agreement with high‐resolution reanalysis in mountainous regions is shown Regional climate models improve accuracy of climate projections for East Asia by simulating local climates at higher resolution than global climate models Regional climate models effectively evaluate potential impacts of local climate variability on specific regions and inform local adaptation strategies The added value of regional climate models in improving global climate models' bias and agreement with high‐resolution reanalysis in mountainous regions is shown

Grasping force estimation using surface Electromyography (sEMG) has been actively investigated as it can increase the manipulability and dexterity of prosthetic hands and robotic hands. Most of the current studies in this area only focus on finding the relationship between sEMG signals and the grasping force without considering the arm posture. Therefore, regression models are not suitable to predict grasping force in various arm postures. In this paper, a method to predict the grasping force from sEMG signals and various grasping postures is developed. The proposed algorithm uses a tensor algebra to train a multi-factor model relevant to sEMG signals corresponding to various grasping forces and postures of the wrist and forearm in multiple dimensions. The multi-factor model is then decomposed into four independent factor spaces of the grasping force, sEMG signals, wrist posture, and forearm posture. Moreover, when a participant executes a new posture, new factors for the wrist and forearm are interpolated in the factor spaces. Thus, the grasping force with various postures can be predicted by combining these factors. The effectiveness of the proposed method is verified through experiments with ten healthy subjects, demonstrating the higher performance of proposed grasping force prediction method than the previous algorithm.

The sensitivity of stratospheric polar vortex variability to the basic‐state stratospheric temperature profile is investigated by performing a parameter sweep experiment with a dry dynamical core general circulation model where the equilibrium temperature profiles in the polar lower and upper stratosphere are systematically varied. It is found that stratospheric variability is more sensitive to the temperature distribution in the lower stratosphere than in the upper stratosphere. In particular, a cold lower stratosphere favors a strong time‐mean polar vortex with a large daily variability, promoting frequent sudden stratospheric warming events in the model runs forced with both wavenumber‐1 and wavenumber‐2 topographies. This sensitivity is explained by the control exerted by the lower‐stratospheric basic state onto fluxes of planetary‐scale wave activity from the troposphere to the stratosphere, confirming that the lower stratosphere can act like a valve for the upward propagation of wave activity. It is further shown that with optimal model parameters, stratospheric polar vortex climatology and variability mimicking Southern and Northern Hemisphere conditions are obtained with both wavenumber‐1 and wavenumber‐2 topographies. Stratospheric polar vortex variability is sensitive to equilibrium temperatures in the lower stratosphereLarge meridional temperature gradients in the lower stratosphere favor extreme fluxes of planetary‐scale waves to the stratosphereSudden stratospheric warming events are frequent when using both wavenumber‐1 and wavenumber‐2 topographies

Characteristics of the tropopause‐level cooling associated with tropical deep convection are examined using CloudSat radar and Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS radio occultation measurements. Extreme deep convection is sampled based on the cloud top height (>17 km) from CloudSat, and colocated temperature profiles from COSMIC are composited around the deep convection. Response of moisture to the tropopause‐level cooling is also examined in the upper troposphere and lower stratosphere using microwave limb sounder measurements. The composite temperature shows an anomalous warming in the troposphere and a significant cooling near the tropopause (at 16–19 km) when deep convection occurs over the western Pacific, particularly during periods with active Madden‐Julian Oscillation (MJO). The composite of the tropopause cooling has a large horizontal scale (~6,000 km in longitude) with minimum temperature anomaly of ~ −2 K, and it lasts more than 2 weeks with support of mesoscale convective clusters embedded within the envelope of the MJO. The water vapor anomalies show strong correlation with the temperature anomalies (i.e., dry anomaly in the cold anomaly), showing that the convectively driven tropopause cooling actively dehydrate the lower stratosphere in the western Pacific region. The moisture is also affected by anomalous Matsuno‐Gill‐type circulation associated with the cold anomaly, in which dry air spreads over a wide range in the tropical tropopause layer (TTL). These results suggest that convectively driven tropopause cooling and associated transient circulation play an important role in the large‐scale dehydration process in the TTL. Convection in the tropics may be expected to hydrate the upper atmosphere. However, over the western Pacific, it dehydrates upper atmosphere by making a significant cooling near the tropopause. Characteristics of the convectively driven cold layer observed from GPS RO dataDehydration of the TTL by the convectively driven cold layerTransient circulation response to deep convection helps dehydration process in the TTL

In numerical weather prediction models, the typhoon track and intensity forecast performances are highly sensitive to physics parameterization schemes. To investigate the impact of physics parameterization schemes on the real‐time short‐term forecasts, we simulated six typhoons which directly/indirectly affected the South Korea region in recent years using the Weather Research and Forecasting (WRF) model. Three cumulus parameterization schemes (CPSs) of Kain‐Fritsch (KF), Betts‐Miller‐Janjić (BMJ), modified Tiedtke (TDK), and two cloud microphysics parameterization schemes (MPSs) of WRF‐single‐moment‐microphysics class 6 (WSM6), Predicted Particle Properties (P3) 1‐category were selected for the sensitivity experiment. The results showed that there was a significant difference in simulated typhoon track and intensity performances depending on the physics schemes. On average, the typhoon forecast performances were improved when applying the KF scheme for CPS and WSM6 scheme for MPS in our experimental setup. The BMJ‐applied runs showed the worst performances, which simulated westward shifted typhoon tracks compared to other runs. Overall, the typhoon track and intensity spreads tended to be more sensitive to CPSs and MPSs, respectively. We conducted additional sensitivity experiments using the BMJ scheme with modified reference and temperature profiles. The result showed that the overactivity of the BMJ scheme at low latitudes was reasonably reduced, leading to the improved simulation of typhoons and synoptic fields. To improve the real‐time short‐term forecast performances for the recent typhoon cases that affected South Korea, sensitivity experiments for the various physics parameterization schemes, such as cumulus parameterization and cloud microphysics schemes, were conducted. Through additional experiments with one of the modified schemes and a comparison of detailed inner cloud processes, the reason for the different track and intensity forecast performances among the sensitivity experiments were revealed. The effect of cumulus parameterization and cloud microphysics schemes on the real‐time forecast of typhoons around South Korea is studiedOne of the cumulus parameterization schemes was modified to decrease its activity at low latitudesEven short‐term typhoon forecasts could be largely affected by the forecast performances of convective processes at the tropics The effect of cumulus parameterization and cloud microphysics schemes on the real‐time forecast of typhoons around South Korea is studied One of the cumulus parameterization schemes was modified to decrease its activity at low latitudes Even short‐term typhoon forecasts could be largely affected by the forecast performances of convective processes at the tropics

The impact of soil moisture initialization on the 2016 Northeast Asian heat wave was explored using the Land Information System (LIS) Weather Research and Forecasting (WRF) model. To obtain advanced soil moisture estimates, various meteorological variables from the Global Data Assimilation System analysis and Integrated Multi‐Satellite Retrievals for Global Precipitation Measurement observation data were used as atmospheric forcings for the offline simulation of the Noah land surface model (Noah‐LSM). Based on the LIS, Soil Moisture Active Passive satellite were assimilated in the Noah LSM simulation. The assimilated soil moisture estimates revealed the drier land surface conditions over Northeast Asia compared with the product from the National Centers for Environmental Prediction Final Analysis (FNL) and were used as the initial condition of the WRF model. The WRF experiment initialized by the assimilated soil moisture product (LIS experiment) exhibited the observed surface air temperature (SAT) and 500 hPa geopotential height (500 GPH) over Northeast Asia compared with the result from the experiment initialized by the FNL (CTL experiment). At Week 1, the LIS experiment simulated warmer SAT than that from the CTL experiment, which was induced by the negative anomaly of latent heat flux over Mongolia. Then, 500 GPH became strong and spatially expanded in response to the thermal low induced by the warmer SAT, and the SAT was further increased during Weeks 2 and 3. The association between soil moisture and land–atmosphere interaction occurring in the East Asia were analyzed by focusing on the 2016 extreme heat wave case. The numerical experiment with the initial soil moisture from the fusion of satellite data and land surface model output simulated a more realistic land–atmosphere interaction over East Asia within a 3‐week heat wave simulation period, compared to the experiment with the operational soil moisture product. The soil moisture estimates assimilated by Soil Moisture Active Passive onto the offline land surface model were initialized in the Weather Research and Forecasting modelAdvanced soil moisture initialization represented the observed land–atmosphere interaction in the 2016 Northeast Asia heat wave The soil moisture estimates assimilated by Soil Moisture Active Passive onto the offline land surface model were initialized in the Weather Research and Forecasting model Advanced soil moisture initialization represented the observed land–atmosphere interaction in the 2016 Northeast Asia heat wave

Spatial and temporal distributions of Clear‐Air Turbulence (CAT) in the Northern Hemisphere were investigated using 41 years (1979–2019) of the European Centre for Medium‐range Weather Forecast Reanalysis version 5 (ERA5) data. We used two groups of CAT diagnostics to determine occurrence frequencies: (a) commonly used empirical turbulence indices (TI1, TI2, and TI3) and their components [vertical wind shear (VWS), deformation, ‐divergence, and divergence tendency], and (b) theoretical instability indicators [Richardson number (Ri), potential vorticity (PV), and Brunt‐Vӓisӓlӓ frequency]. The empirical indices showed high frequencies of moderate‐or‐greater (MOG)‐level CAT potential over the East Asian, Eastern Pacific, and Northwestern Atlantic regions in winter. Over East Asia, the entrance region of strong upper‐level jets showed the highest frequencies in TI1, TI2, and TI3 due mainly to strong VWS. The Eastern Pacific and Northwestern Atlantic areas near the exit region of jets had relatively high frequencies of these indices and also Ri. PV frequency was high on the southern side of jet primarily due to negative relative vorticity. Long‐term increasing trends of MOG‐level CAT potential also appeared in those three regions mainly due to warming in lower latitudes. The most significant increasing trend was found over East Asia, due to the strengthening of the East Asian jet and increased VWS due to the strong meridional temperature gradients in the mid‐troposphere induced by warming in the tropics and cooling in eastern Eurasia. These trends over East Asia, if continued, are expected to be of importance to efficient aviation operations across the northwestern Pacific Ocean. Strong bumpiness of cruising aircraft can lead to physical injuries for crews and passengers, which is mostly occurred due to atmospheric turbulence by enhanced wind shear near upper‐level jet stream. Spatial characteristics of turbulence and their long‐term trends at cruising altitude in Northern Hemisphere were examined using the up‐to‐date global reanalysis data. The result showed that East Asia, Eastern Pacific, and Northwestern Atlantic regions have a higher frequency of turbulence than other areas. In particular, East Asia was found to be the highest frequency and the largest increasing trend of strong turbulence, which is collocated with a heavy air‐traffic region between East Asia and North America across the North Pacific Ocean. This implies that the potential of encountering turbulence over East Asia could be increased further, if the jet stream will be strengthened continually due to climate change in this region. Spatial and temporal distributions of Clear‐Air Turbulence (CAT) indices for 41 years in the Northern Hemisphere are derived using the highest resolution of reanalysis dataThe CAT potentials are high in three regions: the East Asian, Eastern Pacific, and Northwestern Atlantic regions due to upper‐level jetsIncreasing trend of CAT potentials is the largest in East Asia due to warming in tropics and cooling over the Eurasian continent, which have a high impact on transpacific flights Spatial and temporal distributions of Clear‐Air Turbulence (CAT) indices for 41 years in the Northern Hemisphere are derived using the highest resolution of reanalysis data The CAT potentials are high in three regions: the East Asian, Eastern Pacific, and Northwestern Atlantic regions due to upper‐level jets Increasing trend of CAT potentials is the largest in East Asia due to warming in tropics and cooling over the Eurasian continent, which have a high impact on transpacific flights

In the Northwestern Pacific, the meridionally propagating Rossby waves, known as the Pacific‐Japan (PJ) pattern, is the dominant teleconnection pattern and is considered as a source of heatwaves in East Asia. In this study, the circulation and thermodynamic characteristics of these patterns were investigated based on daily timescale to evaluate their relationship with the likelihood of heatwaves in Korea and Japan. The investigations reveal that stations in Korea and Japan record approximately 90% increase in extremely hot days (Tmax> 35°C) during the positive PJ pattern events. According to thermodynamic budget, horizontal heat advection is a key factor for the observed near‐surface warming during the positive PJ. The circulation pattern during the positive PJ largely explains the enhanced warm advection and physical heating due to the increased insolation and adiabatic heating are secondary factors for near‐surface warming. This phenomenon is robustly observed regardless of the definition. In this study, the circulation and thermodynamic characteristics of these patterns were investigated based on daily timescale to evaluate their relationship with occurrence likelihood of heatwaves in Korea and Japan. The investigations reveal that stations in Korea and Japan record approximately 90% increase in extreme hot days during the positive PJ pattern events. According to thermodynamic budget calculations, horizontal heat advection is a key factor for the observed near‐surface warming. Summer temperatures and the likelihood of heatwaves increase significantly over Korea and Japan in the positive Pacific‐Japan (PJ) patternHorizontal heat advection from the subtropical ocean is a key factor for the observed near‐surface warming observed in Korea and JapanPJ‐related near‐surface circulation explains the intense warm advection Summer temperatures and the likelihood of heatwaves increase significantly over Korea and Japan in the positive Pacific‐Japan (PJ) pattern Horizontal heat advection from the subtropical ocean is a key factor for the observed near‐surface warming observed in Korea and Japan PJ‐related near‐surface circulation explains the intense warm advection

The rapid intensification of extratropical cyclones (ETCs) around the Korean peninsula and their surface impacts are investigated by detecting and tracking ETCs in East Asia using ERA‐Interim data over the period of 1979–2017. The ETCs approaching the Korean peninsula, identified on the 850‐hPa relative vorticity field, are mainly initiated in the leeward side of the Altai‐Sayan Mountains and southern Tibetan Plateau, featuring northern and southern cyclone tracks, respectively. The northern‐track ETCs are typically accompanied by a developing upper‐level trough. In particular, those that intensify rapidly are characterized by a strong upper‐level potential vorticity (PV) anomaly related to the enhanced trough, with a rather weak influence of diabatic heating. This is in contrast with the southern‐track ETCs, which are primarily organized by a lower‐level PV anomaly produced by diabatic heating. The southern‐track ETCs rapidly intensify in the presence of a migrating upper‐level trough through the interaction of upper‐ and lower‐level PV anomalies. Although their intensification processes differ, surface winds reaching 10 m s−1are observed with the rapid intensification of both northern‐ and southern‐track ETCs. The southern‐track ETCs, traveling across the East China Sea and the Yellow Sea, also result in substantial precipitation in Korea and Japan. The extratropical cyclones around the Korean Peninsula are primarily generated downstream of the Altai‐Sayan mountains and Tibetan PlateauAn enhanced upper‐level trough is pivotal for the rapid intensification of cyclones with varying contributions from diabatic processesThe rapid intensification is accompanied by a substantial increase in wind speed and precipitation around the Korean Peninsula

Regional models often face a chronic problem caused by inconsistencies between simulated model fields and large‐scale forcing data, which could limit predictability of regional models. Spectral nudging is a technique which can ameliorate this issue by providing large‐scale forcing in the regional model interior. In this study, spectral nudging was applied to tropical cyclone (TC) track and intensity forecasts, and its effects were investigated using a high‐resolution regional model. Case studies on Typhoon Neoguri and Vongfong showed that spectral nudging was effective at enhancing track forecast by improving large‐scale winds and the western North Pacific subtropical high. However, simulated TC intensity was underestimated without the optimization of spectral nudging. Sensitivity tests on spectral nudging options were performed to improve TC intensity while maintaining forecast track improvements. By reducing the nudging coefficient, intensity errors were reduced with a more reasonably developed TC structure. A total of 51 experiments for 18 TCs were conducted with revised spectral nudging options to investigate the general effects of spectral nudging on TC forecasting. The track forecast was generally improved by spectral nudging, especially after 96 hr, and forecast intensity was also improved as compared to experiments without nudging. Furthermore, spectral nudging was especially effective for TCs which occurred to the east of the western North Pacific and turned near Northeast Asia. Therefore, the impact of spectral nudging can be increased by selectively applying spectral nudging based on TC characteristics. The spectral nudging generally improves the TC track forecast with advanced large‐scale fieldsSimulated TC intensity is weakened by spectral nudging, and sensitivity test on nudging options reduces the suppression of TC intensityTrack forecasts can be further improved by selectively applying spectral nudging based on TC characteristics