Abstract:By using the 40a (1961-2000) monthly precipitation data at 60 sites in Jiangsu Province,the spatial and temporal characteristics of summer precipitation anomalies and its related anomalous atmospheric general circulation as well as possible mechanism are investigated.It is found that the anomalies of summer precipitation in Jiangsu Province exhibit two most typical patterns.The first pattern reflects a high spatial consistency of precipitation anomalies,i.e. its general trend;while the second pattern shows an anti-phase relation of precipitaion variation in the northern and southern regions,that is to say,if the precipitaion is more (less) in the southern region,then less (more) in the northern region.Both of the two precipitation patterns exhibit evident interannual variations and are closely related to the latitudinal location of Western Pacific Sub-tropical High (WPSH).However there are still significant differences in their atmospheric circulation background fields.It is also found that SSTAs in different regions and seasons bear intimate relationships to the two precipitaion patterns respectively,which may be one of the factors resulting in the interannual anomalies of Jiangsu summer precipitation.When the SSTA in previous winter in Northern Pacific is warmer (colder),the summer precipitation in all regions of Jiangsu is more (less).Accompanied by the colding (warming) of SSTA in the southern Indian Ocean in previous winter and in the tropical Indian ocean,South China Sea and the sea areas east to the China in spring,the summer precipitation is less (more) in the south and more (less) in the north of Jiangsu.

Abstract:Based on the monthly mean snow depth observations over the Tibetan Plateau and the NCEP/NCAR reanalysis data,the relation between the obvious increasing of the Plateau snow cover and the transition of Asian monsoon circulation since the end of 1970s is analyzed.The results indicate that the increasing of winter or spring snow mass over the Plateau is mainly due to the enhance of the westerly south of the Plateau and the active westerly disturbances in winter and spring.The increasing of snow cover and the weakening of Asian summer monsoon both result from the transition of Asian monsoon circulation.Since the end of 1970s,the increasing of summer rainfall over East China and the decreasing of summer rainfall over South and North China are synchronous with the increasing of snow mass over the Plateau and the weakening of East Asian summer monsoon.The previous winter and spring snow cover over the Plateau positively correlated with the summer rainfall over East China and negatively correlated with the summer rainfall over South and North China on interdecadal time scale.Therefore,the researches about the relation between the Plateau snow cover and the summer rainfall over China should be set under the background of the interdecadal variation of Asian monsoon circulation.

Abstract:Based on the SST and SLP data,the temporal and spatial variations of SSTA in Kuroshio current region have been analyzed in this paper by means of the method of REOF.The results show that there is a spatial change feature as a whole in addition to a remarkable interannual/interdecadal change of SSTA.After dividing the positive and negative SSTA years and analyzing a lot of meteorological elements in corresponding years,it is obtained that the SLP in Kuroshio current region and the height field at 700hPa are negative anomaly with enhancement of winter monsoon in the negative year and vice versa,and that there is a close relation between SSTA of the region and distribution pattern of wind anomaly at 850hPa.

Abstract:As an efficient approach to improve the accuracy of numerical weather prediction (NWP),data assimilation has been received more and more attention.The application of high resolution satellite data to compensate the deficiencies of spatial and temporal resolution in conventional observations in NWP becomes a key subject in this field.As a case,a heavy rainfall process during 28-29 June 1996 occurring in Yangtze-Huaihe river basin is studied with MM5 model.According to the features of physical and energy fields,three sets of quality controlling schemes are designed based on low cloud amount,low level jet and wet static energy respectively.The retrieved relative humidity fields after quality controlling and variational assimilation are used in MM5 model.It is found that the quality controlling improve the prediction of the region and amount of the rainfall greatly.The three quality controlling schemes are effective for rainfall forecast,especially the heavy rainfall.

Abstract:This paper analyzes the spectral characteristics of six major land-surfaces such as desert,forest,grassland,plain,plateau,water-body and snow-cover measured from three most sensitive 23.8,31.4 and 89.0GHz window channels of the AMSU (Advanced Microwave Sounding Unit) abroad on NOAA-16,puts forward a primary algorithm to monitor the snow-cover over Xinjiang by using the measurements from these channels,and obtains the ten-day snow-cover maps of Xinjiang from October 2001 to March 2003.The "point to point" comparison of AMSU monitoring results with ground-based observations shows that the discrimination accuracy is about 70% or higher,and the variational trend of snow-cover percentage accords generally with ground-based observations.Both of these results prove that AMSU data are useful for snow-cover monitoring and the algorithm proposed in this paper is reliable.Besides,the paper simply analyses the factors that influence the monitoring accuracy of AMSU,and then points out several problems to be resolved in the future.

Abstract:After analyzing the observational data,it is considered that there exists the adjust effect of southeasterly draught on the urban heat island in Hefei,and by using the heat balance equation,the impact of the change in the underlying surface southeast of Hefei on the urban mean temperature in summer is analyzed.

Abstract:By using 52-year tropical cyclone (TC) data of the North-Western Pacific,the climatic features of landfall TCs in Zhejiang Province are investigated.Based on the analysis,the landfall TCs are classfied into "enter-sea class" and "disappearing class",and the characteristics such as intensity,maintenance,disappearing location,etc...,of each class TC after landfall,have been studied.

Abstract:By means of a β-plane quasi-geostrophic model and a high resolution f-plane quasi-geostrophic model,six experiments are carried out to investigate the effects of initial tangential wind velocity profile on typhoon track and intensity.Results show that the profile with a narrow region of peak value of tangential wind and a smaller radius of maximum wind is favorable to a north-western track and the maintenance or enhancement of typhoon;on the contrary,a north-turning track and weakening of typhoon happen.

Abstract:A simple method to calculate atmospheric heat over the Tibetan Plateau is constructed based on the monthly average conventional observation data of 198 stations from 1961 to 1995 over the Tibetan Plateau and in its vicinity and the heat source <Q₁> over the Plateau.Using the calculated heat,the climatic characteristics of <Q₁> in various regions and seasons and the relationship between <Q₁> over the Tibetan Plateau in winter and air circulation in spring are also analyzed.The results show that the amount of <Q₁> in the north-eastern part of the Plateau is less than that in the southern part,that the <Q₁> in the each regions presents an upward trend from 1970s to the ealy 1980s and that there exists a negative correlation between the winter heat source over the Plateau and the geopotential height field around the Plateau in spring,which is proved by a climate simulation.

Abstract:Based on the method used in studies of LLJ in North America,A new definition of LLJ in China is given,and the characteristics of LLJ activity are discussed.Results show that there are two LLJ centers locating in Jiangnan and Dongbei respectively;The Jiangnan LLJ is relatively active during January-April and June-July,but the Dongbei LLJ is inactive in February and during August-September;An independent LLJ axis exists from June to August in Jiangnan,but in August in Dongbei;The regional torrential rain in the Yangtze river basin is closely associated with the LLJ during the major rainfall period,and the year with high (low) frequency of LLJ corresponds to a surplus (deficit) precipitation.It is also found that the LLJ in the Yangtze river basin exhibits evident diurnal variation.

Abstract:Based on the theory of the great number law and making reference to calculation methods in U.S.A.,Japan and Taiwan of China,the premium rate of grain yield in the main land of China is formulated compared with the value of other domestic premium rates,the calculated one is equal to the value in quantity but more stable and reliable.The rate is then divided into several risk areas by means of the method of iteration on Self Organization Dynamics Assembling.This result could serve as reference to the operation of insurance company and disaster prevention and alleviation.

Abstract:The dynamic change of the land-use in the Yangtze Delta from 1985 to 1995 is analyzed based on the RS and GIS methods.Which reveals the main types and the features of the range and speed of various land-use change in quantity and its spatial variation.It also describes the local characteristics of land-use change in the Delta area,giving a support to decision maker for a sustainable land utilization.

Abstract:A comprehensive field observation of fog in both the center and suburb of Chongqing is carried on in December 2001,there were two processes of fog in 4th and 29th during that period.By analyzing the two processes of fog,the macro- and micro-physical characters of Chongqing fog in winter are revealed,and the new characters of Chongqing fog after the development of the city are obtained by comparing with the Chongqing fog ten years ago.At last the reason for such change of Chongqing fog is also analyzed.In comparison with the Chongqing fog ten years ago,the duration of fog is shortened,the intensity weakened,and the erupting development postponed;the density of fogdrops is about ten times and the size of fogdrops is one half.The expansion of the city,the reduction of humidity,and the increase of aerosal particle concentration are responsible for such changes of Chongqing fog.

Abstract:In order to accelerate the internationalization of Chinese agriculture after entry into WTO,and to introduce the productive technique of two-line hybrid rice initially invented in China to the world,on the basis of the temperature data of daily four times observations from 1980 to 1997 in Bangkok and Chiang Mai,Tailand,we supplement the missing observations with NCEP/NCAR re-analysis temperature statistics.In terms of calculations of theoretical daylength and fertility conversion index as well as developmental model of Pei’ai 64S,we analyze the climatic adaptability of fertility of photo-thermo-sensitivity male infertility Pei’ai 64S,which is planted most widely in China at present,in Bangkok and Chiang Mai-representative areas of rice production in Tailand,and give the earliest and latest sowing date of safe seed production under the assurance of 90,95 and 100 percent respectively,thus offering a realiable agroclimatic basis for the extention and application of two-line hybird rich technique in Tailand.

Abstract:Relationship between the variations of West Pacific subtropical high indices in summer half year and North Pacific SST in the previous stage is examined based on data of 1951-2000.The correlation between the subtropical high indices and the preceding SST in equatorial East Pacific is the strongest among the areas with great persistency from preceding autumn to spring.It is indicated that ENSO events appeared about a half year earlier than the change of the subtropical high activities and that the subtropical high intensity enhanced (weakened) and west terminal point moved westward (eastward) in the year of El Nino (La Nina) event.The result shows that the distribution of rainfall during rainy season in Fujian is greatly affected by subtropical high activities, which in turn are restricted by ENSO.So it is of significance to pay attention to equatorial East Pacific SST and ENSO information for short-term climate prediction.

Abstract:A one-equation model is developed in this paper to simulate the meteorology and turbulent characteristics of vegetation.Results show that the wind velocity vegetation canopy rapidly decreases near the maximum vegetation leaf area density,then gently approaches to the ground surface.The reynolds stress abruptly decreases downwards from the top of vegetation,rapidly weakens between 0.4 and 0.6 of Z/Hc;At the bottom of vegetation canopy the wind and its shearing are small,the turbulence is also weak,therefore the momentum transfer is trivial.Due to the divergence/convergence of turbulence flux within vegetation,the intensity of turbulence gradually increases upwards from the bottom of vegetation,and approximately keeps constant above vegetation canopy.

Abstract:A large-scale weather process of sandstorm and floating dust,which occured in the west of China and extended to Heilongjiang province on March 20 in 2002,is investigated in the article by using the 3830 Doppler weather radar data and conventional observations.The plane position indications (PPI) and range height indication (RHI) characters of the sandstorm,such as the height,thickness of echoes,the concentration and movement feature of dust,and the horizonal and vertical velocity distribution within the sandstorm,are preliminarily analyzed,thus providing a basis for the minitoring of sandstorms using Doppler weather radar.

Abstract:Using the intensive observation data of the torrential rainfall experiment over the both sides of the Taiwan Strait and adjacent areas,the 5.24 heavy rain in 1998 is analyzed in this paper,and its results are as follows.There is only one strong precipitation period in the middle of this heavy rain process.The relationship between moist available energy E_MA and rainfall is clear.Before the heavy rain occurred, the E_MA remarkably increased;the energy remarkably decreased when the strong precipitation began;there is a narrow recoil of energy during the strong precipitation period;the heavy rain ended when the E_MA remarkably decreased again.This heavy rain is an energy front heavy rain.Before the heavy rain occurred,energy frontogenesis had started,and the heavy precipitation is synchronized with the strong energy front. The area of the heavy rain located in the vicinity of energy precipitation front north of high-energy tongue.