Abstract:Seasonal differences in the SST persistency in the tropical eastern Indian Ocean have been studied using the monthly mean SST data of the GISST dataset and the NCEP/NCAR reanalysis wind and sea surface pressure data.Results indicate that the "fall barrier" of SST persistency existed in the eastern Indian Ocean.By analyzing the lead-lag correlations of the SSTA of the winter Indian Ocean with the SSTA,sea surface pressure and 850 hPa winds over the central-east Pacific Ocean,and by investigating seasonal dif...

Abstract:The echoes and meso-scale system features of the torrential rain in southeastern Hunan caused by the severe tropical storm Bilis between July 14 and 17,2006 was analyzed by using the Doppler radar data in Shaoguan,Guangdong province.The results show that the echoes of Bilis experienced the stages of initial genesis,helix band,merging,decreasing and extinction.The movement of Bilis could be divided into three phases:moving in from northeast to southwest,rotating around the radar station and moving out from s...

Abstract:A heavy rainfall process during 6—7 June 2006 in the Fujian area is simulated by the fine-meshed WRF mesoscale numerical model developed by multi-agency of USA,and a concept model is also constructed.The analysis of the output data indicates that the mesoscale low-vortex was one of the dominant systems in the process and its spatial and temporal evolution characteristics were in accord with the movement and rainfall rate of precipitation center.The disposition of the intensive ascending motion at the center...

Abstract:We simulate the low-temperature and freezing-rain/snow event in southern China during 25th—29th January 2008 by using the WRF model,and the results show that there appeared the coupling of lower and upper level jets over the middle and lower reaches of the Yangtze River and the area south of the river during the rain/snow episode;and the low level jet persistently transported warm/wet air towards the rain/snow area,where the low level moisture convergence promoted the occurrence and maintenance of large-sca...

Abstract:High accuracy of numerical weather prediction(NWP) directly depends on good forecast models and initial conditions.In NWP practice,the adjustments of initial conditions or model parameters according to observational data are meteorological inverse problems.Through the equivalent transformation of the model parameter identification and the adjustment of initial conditions,a new meteorological inverse problems solution based on evolutionary strategy is presented in this paper.Two ideal numerical experiments a...

Abstract:Based on the three-dimensional hail-category hailstorm model developed by Institute of Atmospheric Physics,Chinese Academy of Sciences,simulated in this paper are the macro-and micro-physical processes and the effect of artificial rainfall enhancement and temperature dropping in a operation process of AgI seeding in tropical convective cloud in Haikou,China on 8 July 2004.Results show that,after AgI seeding in the tropical convective cloud,the surface precipitation enhancement and temperature dropping last ...

Abstract:A flash-flood-producing rainstorm occurred in southwest part of the Leizhou Peninsula from 8th to 11th August 2007(briefly "07.8" rainstorm).The formation mechanism,precipitation,dynamic/thermodynamic characters,3D structure and development process of the"07.8" rainstorm are investigated by the MM5 simulations in conjunction with the real-time precipitation,infrared cloud satellite images and radar echoes.Results show that the heavy precipitation simulation is in good accordance with the real location and c...

Abstract:By using the sea level pressure data from NCEP-NCAR reanalysis and monthly mean temperature data from 107 stations in China,the relationships between interannual variations of the Australian high and summer temperature in China have been studied using the SVD singular value decomposition and regression methods.The time series of coefficient of left singular vector of SVD1 was found to be highly correlated with the Australian high index as reported in many studies.The correlation coefficient is 0.97,which sh...

Abstract:Based on the monthly rainfall data at 160 stations in China during 1951—2005,the spatial-temporal variations of summer rainfall anomaly at 17 stations in North China are studied,and the atmospheric circulation factors influencing the rainfall anomaly over North China are discussed.Results show that the total summer rainfall tendency of North China decreases significantly during 1951—2005 with the interannual variations of quasi-three,quasi-six,quasi-eight years and the interdecadal variation of 17—19 years....

Abstract:Based on the pentadly averaged datasets from 1961 to 2005 year,the relationship between the variations of the East Asian subtropical westerly jet(EASWJ) from early summer to midsummer and the withdrawal of Mei-Yu from the Jianghuai region are studied,with the results as follows:(1) during the transforming process of the EASWJ from early summer to midsummer,the westward jump of the jet core from the western Pacific to the Qinghai-Tibet Plateau,and the northward jump of the jet to the area north of 37.5°N ove...

Abstract:By using the routine observational data,two heavy rain processes on the plateau at low latitude in Yunnan from 31 January to 1 February 2007 and from 26—27 January 2008 caused by southern branch trough are compared.The results show that the two processes happened with different circulation backgrounds:the former is a typical Cold Trough-Cold Wave Weather caused by the warm and humid southwesterly,the low level shear and cold front while the later is caused by the establishment and maintenance of the low lev...

Abstract:Based on the daily precipitation at 740 stations in China and the NCEP/NCAR reanalysis data from 1954 to 2003,the possible mechanism for the influence of northeast cold vortex(NECV) on Meiyu in the Yangtze-Huaihe River basin is studied.The results show that when the NECV moves eastward and southward,and meanwhile the western Pacific subtropic high extends westward correspondingly in the middle troposphere.Interactions between the NECV and the western Pacific subtropical high lead to the enhancement of press...

Abstract:By using the NCEP/NCAR reanalysis data(1°×1°),station precipitation and sounding data on 14—15 July 2006,a study on the effects of dry air in the upper troposphere on Bilis rainstorm in Hunan Province was conducted.The results show that there was a large area of dry air between 500 hPa and 200 hPa before the heavy rain occurred.The dry air weakened and disappeared after the heavy rain occurred.There are some correlations between the dry air and the instable energy.The dry air shifted westward with easterly ...

Abstract:Based on homogenized land surface air temperature data at Shenzhen and its neighboring stations and the National Centers for Environmental Prediction/Department of Energy(NCEP/DOE)Atmospheric Model Intercomparison Project(AMIP)-Ⅱ Reanalysis(R-2)data,urbanization effects on temperature change in Shenzhen was estimated.The linear trends of temperature for both the observed and R-2 data were estimated by using the Robust Regression(M estimation),then the contributions of urban heat island(UHI) to the climate w...

Abstract:Based on the planetary boundary layer data measured by an observation system fixed on an observation tower in Dali from March to December 2007,the characteristics of turbulence intensity,standard deviation,turbulence flux and drag coefficient were analyzed by using the eddy correlation method.The results show that turbulence intensity in the dry season was much higher than that in the wet season.The dimensionless standard deviations of 3D winds followed a z/L power law with an exponent of 1/3.The dependence...