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Revisiting the variations of precipitation and water vapour budget over the Tibetan Plateau

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Advances in Climate Change Research 2023年第1期14卷 77-84页

作者： Ping WU Yan-Ju LIU Jing WANG Yi-Hui DING National Climate Center China Meteorological AdministrationBeijing 100081China Tianjin key laboratory for Oceanic meteorology Tianjin Institute of Meteorological ScienceTianjin 300074China

Owing to the scarcity of observation data in the western Tibetan Plateau(TP),the knowledge of precipitation changes over the entire plateau based only on the limited data in eastern TP is not ***,the alternative high-resolution precipitation data of the china Meteorological Forcing Dataset(CMFD)are used for the comprehensive analysis of precipitation changes over the whole TP(including western and northern TP)to fill in the lack of understanding of precipitation in the western *** with observations,CMFD can broadly capture the spatial distributions and identify the temporal variabilities of precipitation over the *** with CMFD data suggested that the annual precipitation over the whole TP did not show a uniform humidification trend in 1979-2018 and featured wetting and drying trends in the northern(NTP)and southern TP(STP),***,the four seasonal regimes of precipitation over the northern TP(NTP,including most areas of western TP)all experienced a noticeable interdecadal shift around the late 1990s,followed by above-normal precip*** for spring,the seasonal precipitation over the southern TP(STP)showed interannual *** precipitation over the STP has undergone moistening since the late 1990s,which was consistent with that over the *** different reanalysis datasets,namely JRA55,MERRA2,ERA5 and CRA40,were used to compare the water vapour budget of each boundary over the *** increase in spring precipitation over the NTP and STP was found to be related to the decrease in water vapour outflow from the north *** interdecadal increase in summer precipitation over the NTP was mainly due to the reduction of outflow from the east ***,the increase in autumn precipitation was related to the increase in inflow from the west boundary.

关键词： Tibetan Plateau Precipitation Water vapour budget Reanalysis data

Transition from the Southern Mode of the Mei-yu Front Cloud System to Other Leading Modes

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Advances in Atmospheric Sciences 2014年第4期31卷 948-961页

作者： QIN Danyu LI Bo HUANG Yong key laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Institute of Satellite meteorology National Satellite Meteorological CenterChina Meteorological Administration School of Atmospheric Physics Nanjing University of Information Science and Technology Anhui Institute of meteorology Science

Based on normalized six-hourly black body temperature （TBB） data of three geostationary meteorological satellites,the leading modes of the mei-yu cloud system between 1998 and 2008 were extracted by the Empirical Orthogonal Function （EOF） method,and the transition processes from the first typical leading mode to other leading modes were discussed and *** analysis shows that,when the southern mode （EOF1） transforms to the northeastern mode （EOF3）,in the mid-troposphere,a low trough develops and moves southeastward over central and eastern *** circulation pattern is characterized by two highs and one low in the lower troposphere.A belt of low pressure is sandwiched between the weak high over central and western china and the strong western North Pacific subtropical high （WNPSH）.Cold air moves southward along the northerly flow behind the low,and meets the warm and moist air between the WNPSH and the forepart of the low trough,which leads to continuous *** the same time,the central extent of the WNPSH increases while its ridge extends *** addition,transitions from the southern mode to the dual centers mode and the tropical-low-influenced mode were found to be atypical,and so no common points could be ***,the choice of threshold value can affect the number of samples discussed.

关键词： black body temperature mei-yu front cloud system leading modes mode transition

Improvement of X-Band Polarization Radar Melting Layer Recognition by the Bayesian Method and ITS Impact on Hydrometeor Classification

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Advances in Atmospheric Sciences 2020年第1期37卷 105-116页

作者： Jianli MA Zhiqun HU Meilin YANG Siteng LI Institute of Urban meteorology China Meteorological AdministrationBeijing 100089China State key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

Using melting layer(ML)and non-melting layer(NML)data observed with the X-band dual linear polarization Doppler weather radar(X-POL)in Shunyi,Beijing,the reflectivity(ZH),differential reflectivity(ZDR),and correlation coefficient(CC)in the ML and NML are obtained in several stable precipitation *** prior probability density distributions(PDDs)of the ZH,ZDR and CC are calculated first,and then the probabilities of ZH,ZDR and CC at each radar gate are determined(PBB in the ML and PNB in the NML)by the Bayesian *** PBB>PNB the gate belongs to the ML,and when PBBPNB the gate belongs to the ML,and when PBB

关键词： X-band polarimetric radar Bayesian method melting layer identification hydrometeor classification

Impacts of Extreme Droughts on Ecosystem Water Use Efficiency Diverge between Forest and Grassland

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Journal of meteorological Research 2023年第5期37卷 710-721页

作者： Mengtian HUANG Panmao ZHAI State key laboratory of Severe Weather and Institute of Global Change and Polar meteorology Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

Ecosystem-scale water use efficiency (WUE),as a quantification of the coupling between carbon and water cycle,determines whether vegetation could survive under severe drought ***,how extreme droughts affect ecosystem-scale WUE and its difference among regions and biomes are still poorly *** this study,using data-oriented gridded products of gross primary productivity (GPP) and evapotranspiration (ET),we assessed the ecosystem WUE change during extreme drought years over china,and further compared drought impacts on WUE between forest and grassland *** found a spatial heterogeneity of WUE change in response to extreme droughts across ***,grassland WUE was substantially reduced concurrent with suppressed photosynthesis,while most of forest exhibited slightly decreased or even increased WUE under extreme *** addition,we demonstrated that drought characteristics and environmental conditions modulated drought impacts on *** anomalies during droughts and leaf area were found to be the predominant factors driving WUE change for both forest and *** increasing occurrence of compound dry and hot extremes,our results,therefore,would be an insightful supplement to the current understanding of the influence of extreme events on terrestrial ecosystems.

关键词： extreme droughts water use efficiency terrestrial ecosystems forest grassland china

THE CHARACTERISTICS OF AIR-SEA HEAT FLUX EXCHANGE DURING THE GENERATION AND DEVELOPMENT OF LOCAL TYPHOONS OVER THE SOUTH china SEA

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Journal of Tropical meteorology 2014年第2期20卷 93-102页

作者：蒋迪黄菲郝光华黄健吕卫华 Physical Oceanography laboratory and key laboratory of Ocean-Atmospheric Interaction and Climate in Universities of Shandong Ocean University of China Ningbo Air Traffic Management Station of Civil aviation Joint Open laboratory of Marine meteorology (JOLMM) Institute of Tropical and Marine Meteorology China Meteorological Administration (CMA)/Guangdong Provincial Key Laboratory of Regional Numerical Weather PredictionChina Meteorological Administration Maoming meteorological Bureau

A South china Sea(SCS) local TC(SLT) is defined as a tropical cyclone(TC) that forms within the SCS region and can reach the grade of tropical storm(TS) or above. The statistical features of the SLTs from 1985 to 2007 are analyzed first. It is found that over the SCS about 68% of the TCs can develop into TSs. The SLT intensity is relatively weak and associated with its genesis latitude as well as its track. The SLT monthly number presents a seasonal variation with two peaks in May and July to September. Based on the daily heat flux data from the Woods Hole Oceanographic Institution_Objectively Analyzed air-sea Fluxes(WHOI_OAFlux) in the same period, the air-sea exchange during the process of generation and development of the SLT is studied. Results show that the heat fluxes released to the atmosphere increase significantly day by day before cyclogenesis. The ocean to the south to the TC center provides the main energy. Along with the development of SLT, the regions with large heat fluxes spread clockwise to the north of TC, which reflects the energy dispersion property of vortex Rossby waves in the periphery of the TC. Once the SLT forms the heat fluxes are not intensified as much. During the whole process, the net heat, latent heat and sensible heat flux display a similar evolution, while the latent heat flux makes a main contribution to the net heat flux. The maximum air-sea heat exchange always occurs at the left side of the TC moving direction, which may reflect the influence of the SCS summer monsoon on TC structure.

关键词： South china Sea local TCs composite heat flux

Detecting sand-dust storms using a wind-profiling radar

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Journal of Arid Land 2017年第5期9卷 753-762页

作者： WANG Minzhong MING Hu HUO Wen XU Hongxiong LI Jiangang LI Xingcai Institute of Desert meteorology China Meteorological Administration Northwest Air Traffic Management Bureau Civil Aviation Administration of China State key laboratory of Severe Weather Chinese Academy of Meteorological Science School of Physics & Electrical Information Engineering Ningxia Key Laboratory of Intelligent Sensing for the Desert Information Ningxia University

Sand-dust storm is a type of disastrous weather, typically occurring in arid and semi-arid climates. This study selected a region in the hinterlands of the Taklimakan Desert, called the Tazhong region, as the experimental area to quantitatively estimate the particle concentrations of sand-dust storms using the boundary layer wind-profiling radar. We thoroughly studied the radar echo signals and reflectivity factor features during the sand-dust storms. The results indicate that（1） under sand-dust storm conditions, boundary layer wind-profiling radar cannot capture the complete information regarding horizontal wind velocity and direction, but it can obtain the backscattering intensity of sand-dust storms; and（2） during sand-dust storms particle size distributions in the surface layer closely resemble log-normal distributions, with sand-dust particles sizes of 90–100 μm accounting for the maximum particle probability. Retrieved particle size distributions at heights of 600, 800, and 1000 m follow log-normal distributions, and the expected value of particle diameter decreases gradually with increasing height. From the perspective of orders of magnitude, the retrieved results for particle number concentrations and mass concentrations are consistent with previous aircraft-detected results, indicating that it is basically feasible to use boundary layer wind-profiling radar to quantitatively detect the particle concentrations of dust storms.

关键词： echo signal mass concentration retrieval method sand-dust storm wind-profiling radar Taklimakan Desert

Evaluating and Improving Wind Forecasts over South china: The Role of Orographic Parameterization in the GRAPES Model

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Advances in Atmospheric Sciences 2018年第6期35卷 713-722页

作者： Shuixin ZHONG Zitong CHEN Daosheng XU Yanxia ZHANG Guangdong Province key laboratory of Regional Numerical Weather Prediction Institute of Tropical and Marine MeteorologyChina Meteorological Administration

Unresolved small-scale orographic（SSO） drags are parameterized in a regional model based on the Global/Regional Assimilation and Prediction System for the Tropical Mesoscale Model（GRAPES TMM）. The SSO drags are represented by adding a sink term in the momentum equations. The maximum height of the mountain within the grid box is adopted in the SSO parameterization（SSOP） scheme as compensation for the drag. The effects of the unresolved topography are parameterized as the feedbacks to the momentum tendencies on the first model level in planetary boundary layer（PBL）parameterization. The SSOP scheme has been implemented and coupled with the PBL parameterization scheme within the model physics package. A monthly simulation is designed to examine the performance of the SSOP scheme over the complex terrain areas located in the southwest of Guangdong. The verification results show that the surface wind speed bias has been much alleviated by adopting the SSOP scheme, in addition to reduction of the wind bias in the lower troposphere. The target verification over Xinyi shows that the simulations with the SSOP scheme provide improved wind estimation over the complex regions in the southwest of Guangdong.

关键词： small-scale orographic drag GRAPES_TMM PBL parameterization wind bias

Turbulence Intensity and Turbulent Kinetic Energy Parameters over a Heterogeneous Terrain of Loess Plateau

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Advances in Atmospheric Sciences 2015年第9期32卷 1291-1302页

作者： YUE Ping ZHANG Qiang WANG Runyuan LI Yaohui WANG Sheng key laboratory of Arid Climatic Change and Reducing Deserter of Gansu Province Institute of Arid MeteorologyChina Meteorological Administration

A deep understanding of turbulence structure is important for investigating the characteristics of the atmospheric boundary layer,especially over heterogeneous *** the present study,turbulence intensity and turbulent kinetic energy（TKE）parameters are analyzed for different conditions with respect to stability,wind direction and wind speed over a valley region of the Loess Plateau of china during December 2003 and January *** purpose of the study is to examine whether the observed turbulence intensity and TKE parameters satisfy Monin–Obukhov similarity theory（MOST）,and analyze the wind shear effect on,and thermal buoyancy function of,the TKE,despite the terrain *** results demonstrate that the normalized intensity of turbulence follows MOST for all stability in the horizontal and vertical directions,as well as the normalized TKE in the horizontal *** shear effect of the wind speed in the Loess Plateau region is strong in winter and could enhance turbulence for all stability *** daytime,the buoyancy and shear effect together constitute the generation of TKE under unstable *** night,the contribution of buoyancy to TKE is relatively small,and mechanical shearing is the main production form of turbulence.

关键词： heterogeneous terrain turbulence intensity turbulent kinetic energy Monin–Obukhov similarity function

Urban effects and summer thunderstorms in a tropical cyclone affected situation over Guangzhou city

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Science china Earth Sciences 2007年第12期50卷 1867-1876页

作者： MENG WeiGuang1,3,YAN JingHua1 & HU HaiBo2 1 Institute of Tropical and Marine meteorology,Chinese meteorological administration(CMA),Guangzhou 510080,china 2 Institute of Urban meteorology,CMA,Beijing 100089,china 3 State key laboratory of Severe Weather,Chinese Academy of meteorological Sciences,Beijing 100081,china Institute of Tropical and Marine meteorology Chinese Meteorological Administration (CMA) Guangzhou China State key laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing China Institute of Urban meteorology CMA Beijing China

With data mainly from Guangzhou mesonet Automatic Weather Stations(AWS),Guangzhou Doppler Radar and satellite TBB data,characteristics and evolution of the urban heat island(UHI) over Guang-zhou City were analyzed in a tropical cyclone affected situation for early August *** particular,two thunderstorms occurring during this period respectively at the night of 4 August and in the afternoon of 7 August were investigated to study the relationships between the development of thunderstorms and the *** showed that two thunderstorms were associated with the UHI *** induced local air convergence and initiated the thunderstorm *** cases showed a general agreement in time and space for the locations of maximum UHI,convergence,convection,and *** was found to be more favorable to developing in time periods and locations with stronger intensity of *** also showed that,due to the urban effects,both thunderstorms got strengthened when moving over Guangzhou City,with maximum radar echoes observed right over the urban area and precipitation located within the *** these features reveal that two thunderstorms were urban-induced storms.

关键词： summer thunderstorms, urban heat islands (UHI), urban effects, tropical cyclone