Abstract:Theoretical and numerical studies are conducted of the effect of the NW-SE oriented upper tropospheric jet axis on divergence genesis to the right of its exit region, showing that as soon as the axis lies in such a direction, vigorous divergence will certainly be formed there owing to the inhomogeneity of the horizontal wind distribution there under the influence of the advection terms.Composite analysis and case study indicate that the NW-SE oriented jet axis and strong divergence happening are considerably earlier compared to the rainstorm occurrence.As such,the change of the orientation of upper tropospheric jet axis is a good indicator in the prediction of rainstorm.

Abstract:Appropriate-time regression method is adapted in the article to estimate moisture field from satellite cloud pictures.Since the regession diagnosis in mathematical statistics is a very effective way to search for singular points,this article's successful application of regression diagnosis into moisture field estimation from satellite cloud pictures improves its accuracy and achieves good results.

Abstract:Through the simulation of climate seasonal change in China, the performance of a regional climate model with p-· incorporated coordinate is tested.The results show that the model can relatively well reproduce the seasonal changes of pressure systems,as well as the seasonal march and withdraw of rainbelt in the east of China.The simulated seasonal characteristics of precipitation in climatic subregions are also basically similar to the observations with discrepancies that the precipitation is underestimated over east and south China in spring and is overestimated over east,southwest and northwest China in autumn. Overall,this model has certain capacity to simulate regional climate in China and can be used as a regional climate model.

Abstract:A statistical model is CCA designed to forecast 3 month mean temperature anomaly in China,which is estimated by using cross verification scheme,indicating that the skill decreases slowly with the increased leading time intervals;higher skills are found for quasi global surface temperature as a predictor;it's easy to predict JAS temperature and hard to deal with OND analog.Some meaningful results are obtained from the forecast skill analysis.

Abstract:Based on discrete ordinate method of radiation transfer in multiple scattering and emitting layered media, computations of solar direct and scattered radiation have been done using the radiosonde observations in southeast of China.Values of solar direct and scattered radiation at different heights have been evaluated in spectral bands.The computed values are then used to set up the statistical relationships with simultaneous satellite observations in VIS/IR.Thus conveniently satellite observed data in the VIS and IR channels may be used to estimate the spatial and temporal distribution of solar direct and scattered radiation in cloudless atmosphere.

Abstract:Spatial distributions of Lemper Ziv complexity of temperature and precipitation time series are discussed.It shows that the complexities of temperature and precipitation variations are about 10~11, which are little than 13, the value of complete random symbol series. The 160-station averaged complexities of annual, seasonal and monthly mean temperature series are increased with the decreasing time scale, i.e., the complexity values of annual and monthly elements are the minimum and maximum of the three time scales.The mean complexity of monthly precipitation is little than that of seasonal and annual series. Spacially, the complexities of temperature and precipitation are larger in the west and north than in the east and south of China, and with the maximum values in the south east coastal areas.

Abstract:Based on biological and plant-shape characteristics of cotton,a model of photosynthetical production of cotton community was modified by dividing the plant into three layers with distance between two neighbouring layers being 1.5 in leaf area index.Photosynthesis was modelled layer by layer and summed up to be total yields.Model test indicates that water and fertilizer being appropriate,it can achieve good results and be useful for field management.

Abstract:Interdecadal features of east Asian monsoon and rainfall over north China and its relation with north Pacific SSTA are investigated by using NCEP/NCAR reanalysis data,SST data and Chinese station precipitation data.It's pointed out that east Asian summer monsoon varies obviously,with the precipitation in north China being abundant during strong east Asian summer monsoon phase before 1976,and the precipitation being deficient after 1976.Results also show that SSTA over north Pacific forces atmosphere mightily,which puts interannual scale “incitation” on interdecadal background field.A wavetrain is strengthened or weakened,by this way that SSTA over north Pacific connects with east Asian summer circulation,which causes the interannual variation of rainfall in north China with more precipitation before 1976,and v.v.after 1976.

Abstract:A detailed study is undertaken of climatic variation features of rainfall and temperature on a monthly,seasonal and annual basis at 4 stations in Zhejiang in terms of 1951~1999 data.Monte Carlo scheme is used to test the long term variation of the meteorological elements.Result shows that the climatic change can also occur in the elements.At last,a method is developed to identify the variability anomaly by means of the sliding mean square deviation.

Abstract:Using NCEP/NCAR 40-year reanalysis, we analyzed the large scale patterns of correlation between the deviations of geopotential height field at 500hPa and the anomalous skin temperature in Eurasia domain during boreal winter.It is found that the geopotential height field correlates much more significantly with skin temperature field than with a field that was artificially built up in a random way.The 4 pairs of coupled spatial pattern obtained with SVD(Singular Value Decomposition) method explain 86% of the total squared covariance between the two variables.These patterns also account for 58% of the total variance of geopotential height field and 38% of the total variance of the temperature field respectively.Two pairs out of 4 show us two zonal circulation anomaly patterns characterized respectively by different latitudinal location of the main disturbances.The other 2 pairs show us two different meridional circulation patterns.The 2 variable fields of the 4 coupled modes seem to be consistent with each other considering the hydrostatic equation.Additionally,the anomalous skin temperature field in fall can be used,to some extent,to predict the sign of the deviation of geopotential height over middle and low latitudes in the coming winter.

Abstract:The anomaly of the blocking high over the North east Asia and the lager scale circulation feature in summer of 1998 are analyzed.The interannual changes of blocking high over the NE Asia, the circulation background and the relationship between the anomaly of blocking high over the NE Asia and SSTA over the Pacific Ocean in summer of 1979~1998 are studied. The results indicate that the “+-+” pattern of 500hPa geopotential height anomaly from high to low latitude is the typical when blocking days are more than normal over the NE Asia,and v.v.The SSTA over the Pacific Ocean causes the teleconnection wave train and the 500hPa geopotential height anomaly over mid high latitude over the East Asia.It might be one of reasons leading to the blocking high anomaly over the NE Asia.Under the circulation background of the higher geopotential height over the mid high latitude, the blocking high over the area of Ural promotes the establishment and development of the blocking high over the NE Asia.The blocking high over the area of Ural happening more frequently than the normal may be one reason of the more blocking high over the NE Asia in summer of 1998.

Abstract:Some numerical experiments are carried out with the improved MM4 model by incorporating with different lateral boundary conditions and topographic forcing as well as the different parameterization schemes of the planetary boundary layer.This helps us to understand the reliability of the model and to verify whether the model is able to simulate the Mei-yu front systems together with the storm events when the Fritsch-Chappell cumulus parameterization scheme is incorporated.A comparison is made between the simulation with Fritsch-Chappell cumulus parameterization and that with Kuo-Anthes scheme.It is found that the forecasting skill of geopotential height and rainfall is signifcantly improved in the improved MM4 model.The improved version of the model is very sensitive to the lateral boundary condition and the topography other than the parameterization scheme of the planetary boundary layer.It should be very careful if the lateral boundary condition or topographic forcing in the model is changed.

Abstract:The advantages of adjoint assimilation to obtain a first estimate field have been theoritically proved with provavility statistics and experimentally verified with ramdomly sampling simulation.The index to evaluate the effectiveness of adjoint assimilation,as well as the method for its calculation are given.

Abstract:By analyzing the variable characteristics of SST in the Indian Ocean during different phases of ENSO cycle,it is found that the correlation of the variation of SST between in the Indian Ocean and in eastern equatorial Pacific is significant,and the variation of SST in the Indian Ocean is an important component of ENSO cycle.The SST pattern in the Indian Ocean is warm in the western part and cold in the eastern part when SST in the eastern equatorial Pacific is warm,and v.v.Furthmore,the results showed that the most significant area of difference of SSTA between in the Western and Eastern Indian Ocean is in 0～25°S.It's interannual and seasonal change is significant.The zonal difference of SST variation in the Indian Ocean during summer monsoon season is more significant than that during winter monsoon season,and the difference during cold phases is larger than that during warm phases.The correlation coefficient is 0.55 between Dipole Mode Index in the Indian Ocean and SSTA in the eastern equatorial Pacific.

Abstract:In order to study the characteristics of natural resources of water in the atmosphere,precipitation in Harbin from May in 1999 was observed 27 times with GBPP 100 produced by PMS Co..In this paper,precipitation data are analyzed to obtain spectrum parameters and their evolution features.Linear and stepwise regression are also used to make a statristical analysis on the linear relationship among the spectral parameters in Γ distribution.

Abstract:Summer monsoon precipitation in 1998 is simulated with different soil temperature and solar short wave radiation parameterization schemes using the improved p-nine level hybrid coordinate model.It is found that the improved soil temperature calculation method together with Lacis and Hansen short wave radiation parameterization has a good simulation for precipitation.Statistical test is also made,indicating that the soil temperature has great impact on the precipitation distribution.Compared with the observed field,this model simulated the precipitation better in some periods,while worse in other periods,such as for the strong precipitation process.

Abstract:The influences of the intensified Ultraviolet radiation(UV-B radiation, 280~400m on both the seed germination and its emergence for both the round-leaf and the angular-leaf spinach are studied in the present article.It is found that the enhanced UV-B tends to decrease both the germination percentage and the emergence rate of round-leaf spinach by retarding the progress of seed germination and the timetable of seedlings and hence to influence the growth of the seedlings.The influences of extra UV-B radiation on the angular spinach seeds are not noticeable.The intensified UV-B radiation seems to effectively prevent the seed germination from the mildew caused by the bacteria.The damage caused by the harmful insects is also decreased when the UV-B radiation is intensified.

Abstract:This paper introduces Windows based programming method of NCAR drawing software to overcome some diagram-making problems in preparing scientific papers, alongside with the investigation of static/dynamic interlinkage during operation,thereby offering necessary knowledge for Fortran programmers on such a kind of microcomputer.

Abstract:Lightning counting data obtained at Xining in 1997 and at Huzhu in 1998 with an SD type counter are analyzed.It is found that the counter can cover an area as large as 40 km in diameter even in the mountainous districts.It is also found that for hail suppression seeding to a thunderstorm lightning flash rate should be ≥40 times/(5min) if the thunderstorm is moving from a mountain area to a plain area and be ≥30 times/(5min) if the thunderstorm is moving from a plain area to a mountain area.The rising gradient of flash rate,if larger than 10 times/(5min),is also indicative of the opportunity for hail suppression.It is concluded that a simple and economic lightning counter is a very useful device for identifying thundercloud and hail producing cloud and for making a decision on the opportunity of hail suppression especially when a weather radar is not available for hail suppression.

Abstract:NOAA monthly Eurasian snowcover area indexes are used to analyze its revolution features,indicating that intermonthly revolution is very complicated with the marked interannual and interdecadal variation.Moreover,its relations are documented to the succeeding climate in China.

Abstract:In the light of the height and streamline space distributions,a visulization scheme called surface streamline mapping is developed to mirror atmospheric movement features on isobaric surfaces objectively with more marked physical meaning compared to routine streamline field drawing method and higher values in a meteorological context.

Abstract:The errors of the airplane altimeter induced by the air temperature and pressure changes as well as the errors of speedometer induced by the air temperature change are analyzed in the present article. The results suggests that the constitution, in which the altitudes for different airlines are given abided by the civil aviation department should be improved. Some schemes are put forward in this paper.