A Tri-mode of Mock-Walker Cells

This work uses cloud-resolving simulations to study mock-Walker cells driven by a specified sea surface temperature(SST).The associated precipitation in the mock-Walker cells exhibits three different modes,including a single peak of precipitation over the SST maximum(mode 1),symmetric double peaks of precipitation straddling the SST maximum(mode 2),and a single peak of precipitation on one side of the SST maximum(mode 3).The three modes are caused by three distinct convective activity center migration traits.Analyses indicate that the virtual effect of water vapor plays an important role in differentiating the three modes.When the SST gradient is large,the virtual effect may be strong enough to overcome the temperature effect,generating a low-level low-pressure anomaly below the ascending branch of the Walker cell off the center.The results here highlight the importance of the virtual effect of water vapor and its interaction with convection and large-scale circulation in the Walker circulation.

Erratum to: A Two-plume Convective Model forPrecipitation Extremes

Erratum to:Yin,Z.H.,P.X.Dai,and J.Nie,2021:A two-plume convective model for precipitation extremes.Adv.Atmos.Sci.,38(6),957−965,https://doi.org/10.1007/s00376-021-0404-8.

Responses of Mean and Extreme Precipitation to Different Climate Forcing Under Radiative-Convective Equilibrium

Understanding the responses of mean and extreme precipitation to climate change is of great importance.Previous studies have mainly focused on the responses to prescribed sea surface warming or warming due to increases of CO2.This study uses a cloud-resolving model under the idealization of radiative-convective equilibrium to examine the responses of mean and extreme precipitation to a variety of climate forcings,including changes in prescribed sea surface temperature,CO2,solar insolation,surface albedo,stratospheric volcanic aerosols,and several tropospheric aerosols.The different responses of mean precipitation are understood by examining the changes in the surface energy budget.It is found that the cancellation between shortwave scattering and longwave radiation leads to a small dependence of the mean precipitation response on forcings.The responses of extreme precipitation are decomposed into three components(thermodynamic,dynamic,and precipitation efficiency).The thermodynamic components for all climate forcings are similar.The dynamic components and the precipitation-efficiency components,which have large spreads among the cases,are negatively correlated,leading to a small dependence of the extreme precipitation response on the forcings.

A Two-plume Convective Model for Precipitation Extremes

In the study of diagnosing climate simulations and understanding the dynamics of precipitation extremes,it is an essential step to adopt a simple model to relate water vapor condensation and precipitation,which occur at cloudmicrophysical and convective scales,to large-scale variables.Several simple models have been proposed;however,improvement is still needed in both their accuracy and/or the physical basis.Here,we propose a two-plume convective model that takes into account the subgrid inhomogeneity of precipitation extremes.The convective model has three components,i.e.,cloud condensation,rain evaporation,and environmental descent,and is built upon the zero-buoyancy approximation and guidance from the high-resolution reanalysis.Evaluated against the CMIP5 climate simulations,the convective model shows large improvements in reproducing precipitation extremes compared to previously proposed models.Thus,the two-plume convective model better captures the main physical processes and serves as a useful diagnostic tool for precipitation extremes.

Review of Chinese atmospheric science research over the past 70 years: Synoptic meteorology

Synoptic meteorology is a branch of meteorology that uses synoptic weather observations and charts for the diagnosis,study,and forecasting of weather.Weather refers to the specific state of the atmosphere near the Earth’s surface during a short period of time.The spatial distribution of meteorological elements in the atmosphere can be represented by a variety of transient weather phenomena,which are caused by weather systems of different spatial and temporal scales.Weather is closely related to people’s life,and its development and evolution have always been the focus of atmospheric scientific research and operation.The development of synoptic meteorology is closely related to the development of observation systems,dynamical theories and numerical models.In China,observation networks have been built since the early 1950 s.Up to now,a comprehensive meteorological observation systembased on ground,air and space has been established.In particular,the development of a new generation of dense radar networks,the development of the Fengyun satellite series and the implementation of a series of large field experiments have brought our understanding of weather from large-scale environment to thermal dynamics,cloud microphysical structure and evolution characteristics of meso and micro-scale weather systems.The development of observation has also promoted the development of theory,numerical model and simulation.In the early days,China mainly used foreign numerical models.Lately,China has developed numerical model systems with independent intellectual property rights.Based on the results of high-resolution numerical simulations,in-depth understanding of the initiation and evolution mechanism and predictability of weather at different scales has been obtained.Synoptic meteorology has gradually changed from an initially independent development to a multidisciplinary approach,and the interaction between weather and the change of climate and environment has become a hot and frontier topic in atmospheric science.This paper reviews the important scientific and technological achievements made in China over the past 70 years in the fields of synoptic meteorology based on the literatures in China and abroad,from six aspects respectively including atmospheric dynamics,synoptic-scale weather,typhoon and tropical weather,severe convective weather,numerical weather prediction and data assimilation,weather and climate,atmospheric physics and atmospheric environment.

On the role of anthropogenic warming and wetting in the July 2021 Henan record-shattering rainfall

Unprecedentedly heavy rains hit China's Henan Province during 19-21 July 2021,triggering fatal and costly floods punctuated by over 120 bllion Yuan of economic losses and nearly 400 fatalities.A broad swath of the province witnessed nearly a whole year's worth of rainfall pouring within the three days.The provincial cap-ital city Zhengzhou even registered 201.9 mm in an hour which smashed the records both locally and nationally.Such concen-trated,intense bursts of precipitation instantly overwhelmed the urban drainage system and sent torrents through streets and sub-way tunnels.Though rapid analyses sorted out favorable dynamic and thermodynamic setups,including exceptionally strong updrafts shaped by large-scale circulation anomalies,unique topography,and anomalously abundant water vapor advected jointly by the Northwestern Pacific subtropical high and double typhoons-In-Fa and Cempaka[1],the linkage between climate change and this record-shattering event also gained broad atten-tions yet remains elusive.

Climate change attribution of the 2021 Henan extreme precipitation: Impacts of convective organization

In this study, we investigate the climate attribution of the 21·7 Henan extreme precipitation event. A conditional storyline attribution method is used, based on simulations of the event with a small-domain high-resolution cloud-resolving model. Large-scale vertical motion is determined by an interactive representation of large-scale dynamics based on the quasigeostrophic omega equation, with dynamical forcing terms taken from observation-based reanalysis data. It is found that warming may lead to significant intensification of both regional-scale(10–14% K, depending on convective organization) and station-scale precipitation extremes(7–9% K^(-1)). By comparing clustered convection organized by a localized surface temperature anomaly and squall-line convection organized by vertical wind shear, we further explored how convective organization may modify precipitation extremes and their responses to warming. It is found that shear convective organization is much more sensitive to large-scale dynamic forcing and results in much higher precipitation extremes at both regional and station scales than unorganized convection is. The clustered convection increases station-scale precipitation only slightly during heavy precipitation events. For regional-scale extreme precipitation sensitivity, shear-organized convection has a larger sensitivity by 2–3% Kthan that of unorganized convection, over a wide temperature range, due to its stronger diabatic heating feedback. For the station-scale extreme precipitation sensitivity, no systemic dependence on convective organization is found in our simulations.