Abstract:WT5BZ]With the snow depth data of ECMWF,the detailed spatial patterns of winter snow anomaly are studied,and the typical anomalous snow patterns are found,the coupling relationships between snow anomaly pattern and winter/summer atmospheric general circulation are discussed with singular value decomposition(SVD)analysis method as well.Results show:(1)winter snow depth anomaly shows its typical spatial patterns;(2)snow anomaly pattern bears coupling relationships to both winter and summer atmospheric general circulations.The anomalous pattern of winter snow depth interacts strongly with atmospheric EU teleconnection pattern.On one hand,the atmospheric EU teleconnection pattern favors to the appearance and maintenance of snow anomaly pattern;on the other hand,the anomalous pattern of snow depth has important impacts on winter atmospheric EU pattern and East Asian winter monsoon.There is also a linkage between snow anomaly pattern and summer atmosphere.Snow anomaly pattern can influence N/S position of western Pacific subtropical high,summer monsoon and summer rainbelt in China.

Abstract:WT5BZ]The technical fundament of forecasting typhoon tracks applying the asymmetric structure theory is expounded.The typhoon Yancy’s (9012) westward movement, the typhoon Doug’s (9414) direction change and the typhoon Fred’s (9417) landing are successfully forecasted applying this theory.

Abstract:WT5BZ]The relationships among the barotropic/baroclinioc modes of tropical wind field and ENSO cycle are investigated in the present paper using a 2 Layer regional ocean model and the NCEP/NCAR reanalysis data as well as GISST sea surface temperature data set. In the central eastern part of tropical Pacific, the phase of variations of baroclinic zonal wind is to some extent leading to the phase of barotropic mode. The phase of time change of barotropic mode is much leading to the phase of sea surface temperature anomalies (SSTA) whose phase at the same time is leading to the phase of baroclinic mode changes. The positive correlation is observed between baroclinic zonal wind and SSTA whereas the negative is observed between the barotropic zonal wind and SSTA. The baroclinic (barotropic) mode tends to increase (decrease) the magnitude of SSTA, which is useful to understand the mechanism of ENSO cycle.

Abstract:WT5BZ]A universal NIM land surface process (LSP) model is proposed to simulate the energy and mass exchanges really between the land surface and the atmosphere in the arid,semi arid and moist regions. The model is made up of the soil model which has two schemes (five layer and two layer model)in the paper and the isothermal vegetation parameterization scheme presented by Chen Wanlong and Shao Haiyan recently. It is tested by using QXPMEX data from May to August in 1979, and the comparison has been done among five layer model,two layer model in the paper and Deardorff’s model(1978). The result shows that this five layer model is superior to Deardorff’s model and the simulated result is also a little better than that of two layer model.

Abstract:The 40-year monthly mean global geopotential height data from the NCEP/NCAR reananlysis project are analyzed by using hemispheric climatic geopot ential height field intensity (I_CF) and an improved spherical function analysis scheme. Results show that there are distinct seasonal and height differences in the global climatic geopotential height intensity.The spherical function spectral structure of climatic geopotential height fields exhibit slow order, low dimension and zonal homogeneity features, which are generally strong in winter,weak in summer,and become st ronger with height except in the seasons of spring and autumn and in the layer of 50～100hPa.Hemipheric differences of climatic geopot ential height fields show that the I_CF is stronger and the low order, low dimension and zonal homogeneity features of spheric function spect ral structure are more evident in the Southern Hemisphere than in the Northern Hemisphere,and the seasonal change in the Southern Hemisphere lags behind for one month than that in the Northern Hemisphere. Those differences are at tributed to the tremendous differences in the area ratioof sea to land, sea and land distribution and topography between the two hemispheres.

Abstract:WT5BZ]In the context of NCEP/NCAR reanalysis daily data in 1998, this paper investigates the features of LFO (low frequency oscillation) structure over the Tibetan Plateau in the summer of 1998.Results show that teleconnection horizontal structures of different low frequencies(LF) have similar wave trains though they exist discrepancy features.LFO structure of principal part of the Plateau is of equivalent barotropic structure.LFP(low frequency precipitation) is generally located at LF cyclonic circulation or LF flow convergence belt.Activities of LFP of south of the Yangtze River and south of the Plateau can be foreshadowed with LFP of the Plateau.LFP strengthens or weakens simultaneously in the Tibetan Plateau and at the low/mid Yangtze Reaches as well as in northeast China.

Abstract:WT5BZ]In the context of NCEP/NCAR daily 500hPa geopotential height during Jun. to Aug. in 1998 investigation is conducted on the quantitative depiction of daily evolution for Eurasian blocking high.Evidence suggests that on the basis of deviations in heights from zonal mean three area indexes are calculated for the Urals, Lake Baikal and Ehuocik areas, respectively,which can well express the daily evolution in intensity and position for the 1998 summer Eurasian blocking highs and bear close relationship with the summer precipitation over China.

Abstract:The 1884~1994 dataset was used to investigate the space/time structures of the anomaly sea level pressure field in relation to mean temperature in northern winters on multi -time scales. The four basic modes whose spatial circulation structures and temporal evolution features, including secular trend, abrupt change and phasic behaviors, were documented, indicating that the mode of the second eigenvector (EOF2) of the pressure associated with the intensity of the Aleutian low bears a close relation to the mean temperature on interannual and interdecadal basis.

Abstract:An EOF interpolation scheme is established and continuous sequences of Northern Hemisphere land surface precipitation is obtained in the period of 1900~1996 with its reasonableness discussed.The dataset is helpful to research the large scale climate change,especially for the change of Northern Hemisphere annual/monthly precipitation in the past 100 years.At last,we made a primary analysis of the Northern Hemisphere land surface precipitation with the dataset.

Abstract:Based on the daily reanalysis data from May to August in 1998,it is found that the transient and quasi permanent structures are different from each other for western Pacific subtropical high(WPSTH).The downdraft in WPSTH center in daily data is mainly caused by the latent heat release in its northern monsoon rainbelt which gives rise to ascending motion there and descending motion in the center,therefrom explaining the mechanism of WPSTH formation and variation.The lagging correlation analysis between convective precipitation rate and area index, and westward extension index of WPSTH indicates that the obvious interaction exists between the westward extension of WPSTH and its surrounding rainbelt.

Abstract:Based on British Bureau global SST,NCEP reanalysis data and 160 stations rainfall data in China, the analysis of composition and SVD is presented.Results show that when the SSTA is the consistent positive (negative) during spring in South China Sea, Bay of Bengal and Arabian Sea,the subtropical high is southern(northern),western(eastern) of its mean position and stronger(weaker),the rainfall is more(less) in the Yangtze River basin and less(more) in south and north of China in summer.

Abstract:A method of retrieving wind from single Doppler radar under local linear assumption is presented.Tangential velocity can be derived from radial velocities along azimuth.Numerical test and case study show that this method is easy to use and has reasonable accuracy.Compared to the traditional VAD method,it can retrieve horizontal wind in relatively small azimuth angle span.

Abstract:Based on recent 50 years data, the analysis of variations in SST and summer rainfall in China has been done.The results show that both of them have similar interdecadal change.Based on it, we carry out numerical study on response of summer rainfall to the anomalous warm SST background in the Pacific in terms of L9R15 model, and find that the numerical results are in agreement with statistical facts.

Abstract:The trends of temperature and precipitation in the north of the Northeast China are studied by using the trend coefficient based on the 1951～1999 data over 6 stations in Heilongjiang Province. Results show that during the recent 10 years there exist more significant ascent trend of summer temperature than that in the period 1951~1999 and the descending trends of spring and autumn temperature and that the precipitation trends have obvious difference in various seasons and various locations, exhibiting the complex characteristics.

Abstract:Based on the data of planet ary albedo, out going long wave radiation(OLR) and total cloud cover provided by ERBE and ISCCP, the effect of the t otal cloud cover on the earth-atmosphere systemnet cloud radiation forcing (NCRF) over the Tibetan Plateau is investigated. So is the relationship between NCRF and clear net radiation. Results show that there is an obvious non-linear correlation between NCRF and the total cloud cover,especially in warm seasons. Also there exists a better curve correlation between NCRF and clear net radiation in the earth-atmosphere system in each month, and each curve has a value of clear net radiation, which varies seasonally with astronomical radiation, corresponding to the zero value of NCRF. The geographical distributions of NCRF are related to total cloud cover and the earth-atmosphere system clear net radiation over the plateau.

Abstract:Based on collecting meteorological yield forecasting models for winter wheat and quantitative analysis of meteorological affecting factors,the primary and secondary meteorological factors affecting winter wheat yield in different areas of China and their affecting periods were found and discussed thoroughly. The conclusions can be used for large area winter wheat yield forecasting.

Abstract:This paper gives Doppler radar radial velocity pictures of Rankine model mesocyclone and describes a technique(GBVTD:Ground Based Velocity Track Display)which uses the ground based Doppler radar data to extract the primary circulation of a mesocyclone. The data of Zhengzhou Doppler radar radial velocity are used to test and verify the method.

Abstract:The quasi periodicities of Chinese average temperature during the recent 100 years are diagnosed by using singular spectrum analysis( SSA). The results show that there exit two dominant periods which range 2~3 years and around 1 year in Chinese average temperature series, which are different from the quasi periodicities of average temperature in Northern Hemisphere at the same time. But their phase variability features of around 1 year periodic oscillation are resemble each other. China is divided into seven segments. SSA shows that the quasi periodic oscillations and their variations with time are different from each other over the seven segments. The periodic oscillations of around 1 year is most prominent in four domains’ temperatures of North, North East, North West China and the Tibetan Plateau. The periodic oscillations of temperature of quasi 2~3 years are most prominent in East, South and South West China.

Abstract:An index which can show the regional features of atmosphere ocean interaction in tropical zones is used in the paper. Correlation between summer rainfall(Jun. to Aug.) in Shandong province and atmosphere ocean interaction in five tropical regions which are the western ,central and eastern Pacific,the Indian Ocean and the Atlantic is analyzed based on the index. The results illustrate that significant correlation exists only between atmosphere ocean interaction in tropic Indian Ocean and summer precipitation in Shandong province. There is probably less(more) summer rainfall in Shandong when Indian Ocean has rather higher(lower) sea surface temperature(SST).In addition, when wind at 1000hPa over western tropic Indian Ocean converges equatorward exceptionally and positive SST anormaly appears simultaneously, dry summer often occurs in the province. Further studies also demonstrate that the changes of summer rainfall in different districts in Shandong province are likely to connect with the weakening of westerly at 1000hPa over tropical Indian Ocean and westward SST gradient.

Abstract:The software design of wheat growth simulation model,which mainly simulates the influences of environment and human activities(such as fertilization,irrigation) on wheat growth,is undertaken with VC⁺⁺,which includes the design scheme,programming and technological analysis.

Abstract:The normal criteria is proved in the paper,which improves the results of Marty,Li Songying and Xie Huichun,and Aulaskari and Lappan,etc.

Abstract:In this paper, we will go a step further to discuss the properties of ST_{-1 separation axiom,introduce the concept of ST0,ST1 separation axiom and study their corresponding separation properties in the TML.}