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Research on the dry intrusion accompanying the low vortex precipitation

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Science china Earth Sciences 2007年第9期50卷 1396-1408页

作者： YAO XiuPing1,2.3. WU GuoXiong1, ZHAO BingKe4, YU YuBin3.& YANG GuiMing2.5 1 LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 10002., {2. 2.Institute of Heavy Rain, china meteorological administration, Wuhan 43.074, {2. 3.1} Training Center, Beijing 100081, {2. 4 Shanghai Typhoon Institute of china meteorological administration, Shanghai 2.003., {2. 5 National meteorological Center of the china meteorological administration, Beijing 100081, {2. LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Institute of Heavy Rain China Meteorological Administration Wuhan 430074 China china meteorological {2. Training Center Beijing 100081 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Shanghai Typhoon Institute of china meteorological administration Shanghai 200030 China china meteorological {2. Training Center Beijing 100081 China Institute of Heavy Rain China Meteorological Administration Wuhan 430074 China National meteorological Center of the china meteorological administration Beijing 100081 China

By employing the 6.7μm satellite vapor cloud images and NCEP/NCAR 1°×1° reanalysis datasets, the characteristics and mechanism of the dry intrusion, as well as its impacts on the low vortex precipita- tion at the Meiyu front are explored in this paper. It is found that the formation,development and main- tenance of the low vortex precipitation at the Meiyu front are closely related to the evolution of the dry intrusion. The dry intrusion is characterized by high potential vorticity (PV), low humidity and cold air. The dry intrusion exhibits as an obvious dark zone on vapor cloud images, an area in which atmos- pheric relative humidity is lower than 60%. However, the features of the dry intrusion on the vapor im- ages are clearer than that of the humidity field, for the former is the digital vapor cloud images with high temporal and spatial resolution, and it can be used to explore the finer characteristics of the develop- ment, evolution and supplement of the intrusion during the development of the low vortex. The dry intrusion impacts accompanying the low vortex precipitation at the Meiyu front come from all levels of the troposphere, with the strongest intrusion located at the upper troposphere. The dry and cold air intrudes the vicinity of the low vortex from the upper isentropic surface to the lower one, slanting eastward from lower to higher level. The low vortex precipitation region is usually situated in front of the dry intrusion where the relative humidity gradient is higher. The research also reveals that the mechanism of the dry intrusion is that the high potential vorticity descends from the upper troposphere to the lower level, therefore, the dry intrusion can be used as an important index of the high PV forcing. To the west of the low vortex precipitation, the upper level northerlies descend across the isentropic surface, then the dry cold advection can trigger the instable development in the mid-low troposphere. The dry intrusion enhances the low vort

关键词： Meiyu front, low vortex precipitation, dry intrusion, mechanisim, vapor image, potential vorticity, relative humidity

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An improvement on summer regional climate simulation over East china: importance of data assimilation of soil moisture

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An improvement on summer regional climate simulation over Ea...

Cloud microphysical and rainfall responses to zonal perturbations of sea surface temperature:A cloud-resolving modeling study

第七届全国优秀青年气象科技工作者学术研讨会

作者： HU YaMin1, 2. DING YiHui3.& LIAO Fei2.1 Guangdong Climate Center, Guangzhou 510080, china 2.Institute of Tropical and Marine {2., china meteorological administration, Guangzhou 510080, china 3.National Climate Center, china meteorological administration, Beijing 100081, china

The Newtonian relaxation is used to assimilate data from the Second Global Soil Wetness Project (GSWP2. into the initial field for soil moisture in a regional climate model (i. e., BCCegCM 1.0, hereinafter called RegCM). The results show that different nudging parameters can improve the simulation of the air temperature and the precipitation to some extent in summertime sea-son over East china. When the nudging intensity is 0.5 and nudging duration is 5 days, the result is desirable. Introducing the data assimilation of soil moisture into RegCM, the amelioration is not only in the spatial distribution pattern but also in the mag-nitude of the temperature and the precipitation. More specifically, the assimilation experiments have corrected the systematical cold bias of the air temperature and the precipitation on the low side, which is much closer to the observation compared with the control experiment. On the whole, the assimilation experiments shed light on the fact that the simulated bias in the original RegCM may be affected by the description of soil moisture in the land surface process. Therefore, the effect of soil moisture in RegCM should be paid more attention in the future.

关键词： soil moisture Newtonian relaxation data assimilation regional climate simulation

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Progress in Natural Science:Materials International 2009年第5期19卷 587-594页

作者： Xiaopeng Cuia, Xiaofan Lib, Zhiping Zongc a Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 10002., china b Joint Center for Satellite Data Assimilation and NOAA/NESDIS/Office of Research and Applications, Camp Springs, MD, USA c National meteorological Center,{2., Beijing 100081, china Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Joint Center for Satellite Data Assimilation and NOAA/NESDIS/Office of Research and Applications Camp Springs MD USA National meteorological Center China Meteorological Administration Beijing 100081 China

The cloud microphysical and rainfall responses to zonal perturbations of sea surface temperature (SST) are investigated by analyzing the equilibrium simulation data (from day 3.-40) obtained from a series of two-dimensional cloud-resolving simulations with a zonal model domain of 768 km. Four experiments imposed by zonal SST perturbations of wavenumbers 1 (SST2.Z1), 2.(SST2.Z2., 4 (SST2.Z4), and 8 (SST2.Z8) are compared to the control experiment imposed by zonally uniform SST (SST2.). The model domain mean SST is 2. °C, and the two-dimensional cloud-resolving model with a cyclic lateral boundary is also imposed by zero vertical velocity and constant zonal wind. The time and model domain mean surface rain rates in SST2.Z1, SST2.Z2. and SST2.Z8 are about 10% larger than those in SST2., whereas the mean surface rain rates in SST2.Z4 and SST2. are similar. The analysis of mean surface rainfall budgets shows that local water vapor and hydrometeor changes play important roles in determining the differences and similarities in mean surface rain rate between the perturbation experiments and the control experiment. Both convective and stratiform rain rates are larger in SST2.Z1 and SST2.Z2.than in SST2. due to the smaller advection of rain from convective regions into raining stratiform regions and the larger vapor condensation rates associated with the larger water vapor convergence over raining stratiform regions in SST2.Z1 and SST2.Z2. The convective rain rates are larger in SST2.Z4 and SST2.Z8 than in SST2. because of the larger condensation rates associated with the larger water vapor convergence over convective regions in SST2.Z4 and SST2.Z8. The stratiform rain rates in SST2.Z4 and SST2.Z8 are smaller than in SST2. due to the smaller vapor condensation rates and smaller collection rates of cloud water by rain over raining stratiform regions in SST2.Z4 and SST2.Z8.

关键词： Cloud microphysical and rainfall responses Sea surface temperature Zonal perturbation Cloud-resolving modeling study

Analysis on a Cold Wave Weather Process in Winter in Gansu

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meteorological and Environmental Research 2011年第11期2卷 25-28页

作者： SUN Yu-lian 1,2.ZHANG Shu-fang 2.ZHANG Li-lu 3.HUANG Cheng-xiu 2.HE Yu-chun 2.1.Lanzhou Institute of Arid meteorology,{2. meteorological {3.,Lanzhou 73.02.,{2. 2.Linxia meteorological Bureau in Gansu,Linxia 73.100,{2. 3.Yongjing meteorological Bureau in Linxia of Gansu,Yongjing 73.600,{2.

[Objective]The research aimed to analyze a cold wave weather process in winter in Gansu.[Method] Based on routine observation data and numerical forecast products,formation reason and physical quantity characteristics of a cold wave process during 2.5 December,2.08 were comprehensively analyzed by synoptic analysis and diagnostic analysis methods.[Result]The cold wave weather belonged to ' translot turning vertical type'.Collapse of the Urals ridge,turning vertical of the translot and strengthening south of the ground cold high induced the cold *** of the Siberian low vortex drove the small branch of cold air in polar region supplementing south,playing certain promoting role in outbreak of the cold *** quantities in the cold wave process also had very good expression,such as vorticity,temperature advection,etc.[Conclusion]This research had important indication effect for early warning,forecast and decision service of the future similar weather process.

关键词： Cold wave Physical quantity characteristics Formation reason Gansu china

Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

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Science china Earth Sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2.& LI YaoKun3.4 1National Marine Environmental Forecasting Center, Beijing 100081, china 2.irst Institute of Oceanography, State Oceanic {2., Qingdao 2.6061, china 3.tate Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 10002., china 4Graduate University of Chinese Academy of Sciences, Beijing 100049, china National Marine Environmental Forecasting Center Beijing China First Institute of Oceanography State Oceanic Administration Qingdao China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

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Influences of greenhouse effect on agricultural production in china

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Journal of Environmental Sciences 1990年第4期2卷 3-10页

作者： Gao Suhua, Ding Yihui, Pan Yaru and Zhao Zongci Academy of meteorological Science,State meteorological {2.,Beijing 100081,{3.

An obvious warming in china induced by doubled carbon, dioxide as simulated by the climatic models have been found. It is also noticed that there might be drying or wetting in some parts of china induced by doubled CO2.as simulated by the general circulation models(GCMs). Agricultural productivity mainly depends on the temperature, rainfall and soil moisture in china. The changes of agricultural productivity in the different parts of china induced by doubled CO2.have been estimated in this paper. It is shown that the greenhouse effect might cause increasing production in some parts of china and decreasing production in other parts of china.

关键词： greenhouse effect agricultural productivity doubled CO2 GCMs climatic productivity force.

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The Application of Superimposed Marcov Chain for Prediction of Annual Precipitation

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meteorological and Environmental Research 2011年第11期2卷 5-7页

作者： LIAO Jie,HU Hao-ran,CHEN Gong Institute of Plateau meteorology,china {2. {3.,Chengdu 610072.china

[Objective] The aim was to predict the annual precipitation using the method of Superimposed Marcov Chain.[Method] Based on annual precipitation in Xiaojin station on western Sichuan Plateau during 1961-2.10,the Superimposed Marcov Chain method was applied to predict annual precipitation from 2.01 to *** prediction based on the Superimposed Marcov Chain method was compared with the observed data.[Result] For the ten years (2.01-2.10),the relative error in 7 years was less than 10%,even less than 5% in 4 years,which proved that Superimposed Marcov Chain can predict annual *** this method had certain defect in prediction in the extreme dry or extreme wet years,and that needs to be improved in the following study.[Conclusion] The Superimposed Marcov Chain method had clear concept,was convenient to calculate,and provided a way to explore the improvement of precipitation prediction.

关键词： Superimposed Markov Chain Annual precipitation Prediction Plateau china

Analysis on the Influence of Spring Low Temperature on the Agriculture and the Formation Reason in Liaoning Province in 2.10

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meteorological and Environmental Research 2011年第4期2卷 15-17页

作者： HAN Xiu-jun1, YU Xiao-li2. WANG Gui-chun3.1. Liaoning meteorological Observatory, Shenyang 110016, {2. 2. Dalian meteorological Bureau in Liaoning Province, Dalian 116001, {2. 3. Jinzhou meteorological Bureau in Dalian City of Liaoning Province, Jinzhou 116100, {2.

[Objective] The research aimed to study the influence of spring low temperature on the agriculture and the formation reason in Liaoning Province in 2.10. [Method] Based on the synoptics analysis principle, by analyzing the atmospheric circulation situation and satellite cloud map, the influence of spring low temperature on the agriculture and the formation reason of low temperature weather in Liaoning Province during April-May, 2.10 were discussed. [Result] The high-altitude situation analysis showed that it was two-trough-two-ridge situation in the high latitude of Eurasia in April, 2.10. Ural Mountains high-pressure ridge strengthened to move eastward. Lake Baikal cold air went down toward the southeast along the front of ridge and strengthened into the cold vortex. Liaoning was in the front of cold vortex. Affected by the cold vortex, the temperature in Liaoning area was low. In the first dekad of May, 2.10, the activity of cold air was frequent. There were two times cold vortex influence, and the temperature was still low. In the later period of middle dekad of May, the warm ridge entered, and the temperature rose. The high-altitude trough and the low-level jet were the main system and the dynamic condition of precipitation generation respectively. The cold vortex was the main reason of spring continuous low temperature generation, and the secondary reason was the more precipitation. [Conclusion] The research provided the reference basis for the prevention and prediction of spring low temperature in Liaoning Province.

关键词： Spring low temperature Agricultural influence Formation reason analysis Liaoning Province china

Analyses on Climate Characteristics in Xingtai City during 1954 - 2.10

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meteorological and Environmental Research 2011年第11期2卷 23-24,28页

作者： LIU Jun1,CHENG Xiao-hui2.HUANG Rong3.4 1.Observation and Network Department,Hebei meteorological Bureau,Shijiazhuang 05002.,{2. 2.Xingtai meteorological Bureau in Hebei Province,Xingtai 054000,{2. 3.Beijing Institute of Urban meteorology,{2. meteorological administration,Beijing 100089,{2. 4.{2. Academy of meteorological Sciences,Beijing 100081,{2.

[Objective] The research aimed to analyze climate characteristics in Xingtai City during 1954-2.10.[Method] Based on climate data in Xingtai City during 1954-2.10,by using line chart,trend chart,climatic variability and statistical diagram,the climate characteristics in Xingtai City in 57 years were analyzed.[Result] The annual average temperature,annual average maximum and minimum temperatures in Xingtai City during 1954-2.10 all presented gradual rise *** rise velocity of annual average maximum temperature was the *** annual average temperature presented rise trend year by *** rise velocity of annual average minimum temperature was the *** annual average rainfall,wind speed,relative humidity and sunshine hours all presented gradual decline trend,while the annual average total cloud amount presented increase *** annual average ground temperatures at 0,5,10,15 and 2. cm in Xingtai City during 1954-2.10 were respectively 15.6,15.7,15.8,15.8 and 15.8 ℃.The annual average ground temperatures at 40 and 80 cm,1.6 and 3.2.m in Xingtai City during 1981-2.10 were respectively 15.2.15.2.15.4 and 15.4 ℃.It was clear that the ground temperature at deep layer gradually rose as depth increase.[Conclusion] The research provided theoretical basis for guiding agricultural production in Xingtai City.

关键词： Xingtai City Climate characteristics Analysis china