Accurately simulating mesoscale convective systems(MCSs)is essential for predicting global precipitation patterns and extreme weather events.Despite the ability of advanced models to reproduce MCS climate statistics,c...Accurately simulating mesoscale convective systems(MCSs)is essential for predicting global precipitation patterns and extreme weather events.Despite the ability of advanced models to reproduce MCS climate statistics,capturing extreme storm cases over complex terrain remains challenging.This study utilizes the Global–Regional Integrated Forecast System(GRIST)with variable resolution to simulate an eastward-propagating MCS event.The impact of three microphysics schemes,including two single-moment schemes(WSM6,Lin)and one double-moment scheme(Morrison),on the model sensitivity of MCS precipitation simulations is investigated.The results demonstrate that while all the schemes capture the spatial distribution and temporal variation of MCS precipitation,the Morrison scheme alleviates overestimated precipitation compared to the Lin and WSM6 schemes.The ascending motion gradually becomes weaker in the Morrison scheme during the MCS movement process.Compared to the runs with convection parameterization,the explicit-convection setup at 3.5-km resolution reduces disparities in atmospheric dynamics due to microphysics sensitivity in terms of vertical motions and horizontal kinetic energy at the high-wavenumber regimes.The explicit-convection setup more accurately captures the propagation of both main and secondary precipitation centers during the MCS development,diminishing the differences in both precipitation intensity and propagation features between the Morrison and two single-moment schemes.These findings underscore the importance of microphysics schemes for global nonhydrostatic modeling at the kilometer scale.The role of explicit convection for reducing model uncertainty is also outlined.展开更多
This study investigates the capabilities of a non-hydrostatic global,variable-resolution model in simulating tropical cyclone precipitation,with historically significant Typhoon Fitow(1323)as a case study.Employing th...This study investigates the capabilities of a non-hydrostatic global,variable-resolution model in simulating tropical cyclone precipitation,with historically significant Typhoon Fitow(1323)as a case study.Employing three grid settings(24 km,60−10 km,60−3 km)and two microphysical parameterization schemes(WSM6 and Thompson),the study investigates the influence of grid resolution and microphysical parameterization on precipitation simulation.The simulated precipitation intensity and spatial distribution of high-resolution grids exhibit better agreement with the observations compared to the coarse-resolution grids.Specifically,the 60−3 km grid setting shows the greatest improvement in spatial correlation with observed precipitation data compared to the 24 km grid.Through the analysis of the thermal dynamic field,the high-resolution grid configuration more effectively simulates indicators for strong convective weather events,such as convective available potential energy(CAPE),helicity,and nonadiabatic heating.Analysis of TRMM satellite observations reveals that the high-resolution grid simulation results more accurately capture the distribution characteristics of hydrometeor mixing ratio compared to the coarse-resolution grids.Differences in hydrometeor content within convective clouds are more pronounced across grid resolutions than in stratiform clouds,even with the same parameterization scheme.Additionally,at the same resolution,the disparity in ice-phase particle content between the two schemes is much greater than the disparity in liquid-phase particle content.It is also noteworthy that the WSM6 scheme delivers superior performance compared to the Thompson scheme.In summary,this study demonstrates that refining model resolution has a more significant impact on precipitation intensity than the selection of physical parameterization scheme.The Model for Prediction Across Scales(MPAS),using a high-resolution variable-resolution grid,can be effectively used for typhoon precipitation simulation research.展开更多
Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems.Here we take the recor...Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems.Here we take the record-breaking precipitation over China in 2021 as an example,and study its changes under three different climate scenarios through a developed pseudo-global-warming(PGW)experimental framework with 60-3 km variable-resolution global ensemble modeling.Compared to the present climate,the precipitation extreme under a warmer(cooler)climate increased(decreased)in intensity,coverage,and total amount at a range of 24.3%-37.8%(18.7%-56.1%).With the help of the proposed PGW experimental framework,we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme.Under the warmer climate,large-scale water vapor transport converged from double typhoons and the subtropical high marched into central China,enhancing the convective energy and instability on the leading edge of the transport belt.As a result,the mesoscale convective system(Mcs)that directly contributed to the precipitation extreme became stronger than that in the present climate.On the contrary,the cooler climate displayed opposite changing characteristics relative to the warmer climate,ranging from the large-scale systems to local environments and to the Mcs.In summary,our study provides a promising approach to scientifically assess the response of precipitation extremes to climate change,making it feasible to perform ensemble simulations while investigating the multi-scale system interactions over the globe.展开更多
A double-plume convective parameterization scheme is revised to improve the precipitation simulation of a global model(Global-to-Regional Integrated Forecast System;GRIST).The improvement is achieved by considering th...A double-plume convective parameterization scheme is revised to improve the precipitation simulation of a global model(Global-to-Regional Integrated Forecast System;GRIST).The improvement is achieved by considering the effects of large-scale dynamic processes on the trigger of deep convection.The closure,based on dynamic CAPE,is improved accordingly to allow other processes to consume CAPE under the more restricted convective trigger condition.The revised convective parameterization is evaluated with a variable-resolution model setup(110–35 km,refined over East Asia).The Atmospheric Model Intercomparison Project(AMIP)simulations demonstrate that the revised convective parameterization substantially delays the daytime precipitation peaks over most land areas,leading to an improved simulated diurnal cycle,evidenced by delayed and less frequent afternoon precipitation.Meanwhile,changes to the threshold of the trigger function yield a small impact on the diurnal amplitude of precipitation because of the consistent setting of dCAPE-based trigger and closure.The simulated mean precipitation remains reasonable,with some improvements evident along the southern slopes of the Tibetan Plateau.The revised scheme increases convective precipitation at the lower levels of the windward slope and reduces the large-scale precipitation over the upper slope,ultimately shifting the rainfall peak southward,which is in better agreement with the observations.展开更多
This study provides a preliminary evaluation of the ensemble forecasting capabilities of the Model for Prediction Across Scales-Atmosphere(MPAS-A)for tropical cyclones(TCs)affecting Zhejiang Province and adjacent offs...This study provides a preliminary evaluation of the ensemble forecasting capabilities of the Model for Prediction Across Scales-Atmosphere(MPAS-A)for tropical cyclones(TCs)affecting Zhejiang Province and adjacent offshore waters in the East China Sea.Five recent high-impact TCs were retrospectively simulated using a global 60-3 km variable-resolution mesh and an eight-member ensemble that samples key physics parameterizations,including cumulus,microphysics,boundary layer,and surface layer schemes.Ensemble-mean and spread characteristics of track and intensity forecasts were assessed against best-track data from the China Meteorological Administration(CMA),while near-surface wind predictions were evaluated using tower-based observations during Typhoon Muifa(2022).Track forecasts exhibited promising skill,with median errors under 50 km at 24 h and 100 km at 48 h,while the ensemble mean was typically more accurate than the median and comparable to operational forecasts.Intensity forecasts showed larger spread and systematic biases,particularly in maximum wind speed,highlighting the influence of boundary-layer physics on ensemble variance.Case studies illustrate how differing physics choices drive divergence in storm translation,steering flow,and inner-core structure.Comparison with tower observations confirmed that the ensemble has the potential to bracket uncertainty in near-surface wind forecasts,although storm position errors remain a key limiting factor.Despite high computational cost,MPAS-A ensembles demonstrate strong potential for probabilistic TC forecasting and offshore wind risk management in this region.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42305169)the Basic Research Fund of CAMS(Grant No.2023Y001)the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulation Facility”(Earth Lab)。
文摘Accurately simulating mesoscale convective systems(MCSs)is essential for predicting global precipitation patterns and extreme weather events.Despite the ability of advanced models to reproduce MCS climate statistics,capturing extreme storm cases over complex terrain remains challenging.This study utilizes the Global–Regional Integrated Forecast System(GRIST)with variable resolution to simulate an eastward-propagating MCS event.The impact of three microphysics schemes,including two single-moment schemes(WSM6,Lin)and one double-moment scheme(Morrison),on the model sensitivity of MCS precipitation simulations is investigated.The results demonstrate that while all the schemes capture the spatial distribution and temporal variation of MCS precipitation,the Morrison scheme alleviates overestimated precipitation compared to the Lin and WSM6 schemes.The ascending motion gradually becomes weaker in the Morrison scheme during the MCS movement process.Compared to the runs with convection parameterization,the explicit-convection setup at 3.5-km resolution reduces disparities in atmospheric dynamics due to microphysics sensitivity in terms of vertical motions and horizontal kinetic energy at the high-wavenumber regimes.The explicit-convection setup more accurately captures the propagation of both main and secondary precipitation centers during the MCS development,diminishing the differences in both precipitation intensity and propagation features between the Morrison and two single-moment schemes.These findings underscore the importance of microphysics schemes for global nonhydrostatic modeling at the kilometer scale.The role of explicit convection for reducing model uncertainty is also outlined.
基金financially supported by the National Key Research and Development Program of China(No.2021YFC3000802)supported by the ECNU Multifunctional Platform for Innovation(001).
文摘This study investigates the capabilities of a non-hydrostatic global,variable-resolution model in simulating tropical cyclone precipitation,with historically significant Typhoon Fitow(1323)as a case study.Employing three grid settings(24 km,60−10 km,60−3 km)and two microphysical parameterization schemes(WSM6 and Thompson),the study investigates the influence of grid resolution and microphysical parameterization on precipitation simulation.The simulated precipitation intensity and spatial distribution of high-resolution grids exhibit better agreement with the observations compared to the coarse-resolution grids.Specifically,the 60−3 km grid setting shows the greatest improvement in spatial correlation with observed precipitation data compared to the 24 km grid.Through the analysis of the thermal dynamic field,the high-resolution grid configuration more effectively simulates indicators for strong convective weather events,such as convective available potential energy(CAPE),helicity,and nonadiabatic heating.Analysis of TRMM satellite observations reveals that the high-resolution grid simulation results more accurately capture the distribution characteristics of hydrometeor mixing ratio compared to the coarse-resolution grids.Differences in hydrometeor content within convective clouds are more pronounced across grid resolutions than in stratiform clouds,even with the same parameterization scheme.Additionally,at the same resolution,the disparity in ice-phase particle content between the two schemes is much greater than the disparity in liquid-phase particle content.It is also noteworthy that the WSM6 scheme delivers superior performance compared to the Thompson scheme.In summary,this study demonstrates that refining model resolution has a more significant impact on precipitation intensity than the selection of physical parameterization scheme.The Model for Prediction Across Scales(MPAS),using a high-resolution variable-resolution grid,can be effectively used for typhoon precipitation simulation research.
基金supported by the National Natural Science Foundation of China(42225505)the Beijing Nova Program(Z211100002121100)+2 种基金the National Key Research and Development Program of China(2021YFC3000805)the National Natural Science Foundation of China(U2142204)the Science&Technology Development Fund of Chinese Academy of Meteorological Sciences(CAMS)(2022KJ007)。
文摘Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems.Here we take the record-breaking precipitation over China in 2021 as an example,and study its changes under three different climate scenarios through a developed pseudo-global-warming(PGW)experimental framework with 60-3 km variable-resolution global ensemble modeling.Compared to the present climate,the precipitation extreme under a warmer(cooler)climate increased(decreased)in intensity,coverage,and total amount at a range of 24.3%-37.8%(18.7%-56.1%).With the help of the proposed PGW experimental framework,we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme.Under the warmer climate,large-scale water vapor transport converged from double typhoons and the subtropical high marched into central China,enhancing the convective energy and instability on the leading edge of the transport belt.As a result,the mesoscale convective system(Mcs)that directly contributed to the precipitation extreme became stronger than that in the present climate.On the contrary,the cooler climate displayed opposite changing characteristics relative to the warmer climate,ranging from the large-scale systems to local environments and to the Mcs.In summary,our study provides a promising approach to scientifically assess the response of precipitation extremes to climate change,making it feasible to perform ensemble simulations while investigating the multi-scale system interactions over the globe.
基金supported by the National Key R&D Program of China on the Monitoring,Early Warning,and Prevention of Major Natural Disasters(Grant Nos.2018YFC1507005 and 02017YFC1502202)。
文摘A double-plume convective parameterization scheme is revised to improve the precipitation simulation of a global model(Global-to-Regional Integrated Forecast System;GRIST).The improvement is achieved by considering the effects of large-scale dynamic processes on the trigger of deep convection.The closure,based on dynamic CAPE,is improved accordingly to allow other processes to consume CAPE under the more restricted convective trigger condition.The revised convective parameterization is evaluated with a variable-resolution model setup(110–35 km,refined over East Asia).The Atmospheric Model Intercomparison Project(AMIP)simulations demonstrate that the revised convective parameterization substantially delays the daytime precipitation peaks over most land areas,leading to an improved simulated diurnal cycle,evidenced by delayed and less frequent afternoon precipitation.Meanwhile,changes to the threshold of the trigger function yield a small impact on the diurnal amplitude of precipitation because of the consistent setting of dCAPE-based trigger and closure.The simulated mean precipitation remains reasonable,with some improvements evident along the southern slopes of the Tibetan Plateau.The revised scheme increases convective precipitation at the lower levels of the windward slope and reduces the large-scale precipitation over the upper slope,ultimately shifting the rainfall peak southward,which is in better agreement with the observations.
基金supported by Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ24D050001.
文摘This study provides a preliminary evaluation of the ensemble forecasting capabilities of the Model for Prediction Across Scales-Atmosphere(MPAS-A)for tropical cyclones(TCs)affecting Zhejiang Province and adjacent offshore waters in the East China Sea.Five recent high-impact TCs were retrospectively simulated using a global 60-3 km variable-resolution mesh and an eight-member ensemble that samples key physics parameterizations,including cumulus,microphysics,boundary layer,and surface layer schemes.Ensemble-mean and spread characteristics of track and intensity forecasts were assessed against best-track data from the China Meteorological Administration(CMA),while near-surface wind predictions were evaluated using tower-based observations during Typhoon Muifa(2022).Track forecasts exhibited promising skill,with median errors under 50 km at 24 h and 100 km at 48 h,while the ensemble mean was typically more accurate than the median and comparable to operational forecasts.Intensity forecasts showed larger spread and systematic biases,particularly in maximum wind speed,highlighting the influence of boundary-layer physics on ensemble variance.Case studies illustrate how differing physics choices drive divergence in storm translation,steering flow,and inner-core structure.Comparison with tower observations confirmed that the ensemble has the potential to bracket uncertainty in near-surface wind forecasts,although storm position errors remain a key limiting factor.Despite high computational cost,MPAS-A ensembles demonstrate strong potential for probabilistic TC forecasting and offshore wind risk management in this region.
