Vol.6, NO.1, 1995

Display Method:
The Experiment of Regional Four-dimensional Data Assimilation Scheme
Zhu Zongshen, MaQingyun, Zheng Guoan
1995, 6(1): 1-8.
A regional four-dimensional intermittent data assimilation scheme has been developed by using the analysis scheme, initialization scheme and model scheme of limited area analysis and forecast system (LAFS) in NMC in China. Some forecast experiments of heavy rains in China in 1992 are made by using the assimilation scheme. The experiment results show that the skill of forecast both weather system and rainfall from the assimilation initial values, especially from those of fine-mesh scheme, is much better than the skill of control forecast based on LAFS scheme.
Mesoscale Convective Complexes over the Southern China Mainland
Xiang Xukang, Jiang Jixi
1995, 6(1): 9-17.
Ten mesoscale convective complexes (MCCs) over the southern China mainland during late spring and early summer were computed and analysed using GMS S-VISSR data and conventional data. The results show that they are nocturnal and initiate at slope or near slope bottom of plateau or mountains leeward, and develop at the special favorable area where several synoptic systems from low- and mid–latitude are merging or interacting with each other. They move toward east by south and tend to the mean flow in 700~500 hPa layer. The cold-cloud-shield is about 1.4×105km2, which is smaller than that of MCC in the America ((2~3)×105km2), but it lasts for about 12 hours while the American shield about 10 hours. The eccentricity of cloud shape (≥0.6) is slightly smaller than that in the America (≥0.7). The minimum temperature of cloud top is generally colder than -86℃, which appears 4~6 hours earlier than the time of the maximum cold-cloud-shield extent
An Analysis of Two Sandstorms in Spring 1990
Yang Dongzhen, Wang Chao, Wen Yupu, Yu Xiaolan, Xiu Xiaobin
1995, 6(1): 18-26.
Two cases of sandstorm processes, which occurred in April 1990, were studied. The characteristics of this kind of weather and the reason causing the events are investigated. Through analyzing the samples in collected Yulin, Yan’an, Taiyuan, Hohhot and Beijing, and calculating the sandstorm trajectories, some chemical and physical features are revealed and the source areas are found. In the periods of sandstorm activity the total suspended particulates (TSP) concentrations are higher than normal by several times upto about one order of magnitude. The aerosols of sandstorm consist of mainly the natural lithosphere elements from earth crust, which distribute in large particles (d >2.1 μm). The polluted elements from human activity exist in small particles (d<2.1μm), and their enrichment factors are sharply reduced during the sandstorm.
Influences of Pinatubo Volcanic Clouds on Large Scale Climate in 1992
xu Qun
1995, 6(1): 35-42.
Nearly 20 megaton sulfuric aerosols were erupted to the stratosphere during mid-June of 1991. It is the strongest event with maximal volcanic clouds since the beginning of present century. The dispersion of volcanic clouds in the stratosphere and their cooling effect on large scale climate in 1992 is discussed. It is shown that the global average temperature has pronounced drop, and the climatically cool regions in northern summer-autumn of 1992 appear significant from the tropics to higher latitudes. Furthermore, a series of cool injury events appeared in the summer of the year in China.
Flow Field on a Two-dimensional Wave from Orography
Wen Shigeng
1995, 6(1): 27-34.
In a two-layer model, the wave equation is solved to obtain the resolution analytically of disturbed streamlines caused by a two-dimensional sinusoidal topography. The disturbed flow field in the upper and lower layers for varieties of temperature and wind profiles is studied. The atmospheric conditions and the topographic feature determining the amplitude of the disturbances are also discussed. The results show that the waves induced by the terrain are weaker if the lower layer of the atmosphere is deep and unstable, while the waves are stronger if the lower layer is strongly stable with a weakly stable in upper layer. The increase of the stability in the upper layer may induce untrapped waves which favour the downward transport of momentum and the formation of the strong surface wind
A Study of Extratropical Cyclone over Oceans Near Australia in the Southern Winter
Yang Zufang, Wang Wendong
1995, 6(1): 43-49.
Using GMS IR images and conventional and grid data over the southern Hemisphere during the winters of 1990~1992, the initiating regions and tracks of extratropical cyclones in each of months are investigated and four composite models of cloud patterns evolution for extratropical cyclone generating, developing and weakening are summarized. A primary method of estimating its center pressure is provided.
Analyses of Unusual First and Last Frost During the Last 40 Years in the Changjiang and Huaihe River Valley
ChenQianjin, Xia Hongxing, Zhang Yongshan
1995, 6(1): 50-55.
According to the frost index defined by the soil surface minimum temperature ≤0℃, the criterion for the unusual frost was quantitatively given and the climatic features of the unusual first and last frost during the last 40 years were studied. The results show that there distinct geographical differences in the unusual first and last frost days, and 2~3 year and guasi-12 year cycles are universal. Roughly, two fluctuation patterns are discovered. One is the opposite tendency between the first and last frost days and the other is the same fluctuation tendency between them. The former is obvious in the Huaihe River Valley and the latter is generally in the Changjiang River Valley. When the departures of the first or last frost come into being the opposite tendency or the same one and their departures to the average reach the largest, the frost periods are defined as unusual active one.
Evolution and Fine Structure of a Heavy Precipitation System
XueQiufang, Ding Yihui, Wang Jianzhong
1995, 6(1): 56-62.
A heavy precipitation system occurring in the eastern plain of Hebei province in summer is analysed based on the detail data. Evolution and fine structure of the meso-αscale convective system are studied. And the physical mechanism of warm regions forming in this system is investigated. The results show that the interaction between different scale system has greats effects on the event.
An Analysis of Moist Available Energy About an Inland Typhoon
Liu Yanying
1995, 6(1): 63-69.
Using new formulae of moist available energy (MAE), the typhoon T8108 was studied and its three components of MAE during the various periods were calculated. The results show that the system of typhoon has a high energy, its MAE in the stage of the extratropical cyclone is more than that in the stage of the tropical typhoon. The changes of MAE is mainly due to the variance of barotropic and baroclinic components. And different energy characteristics appear in different periods of typhoon rain. The expenditure of energy for the typhoon rain is mainly from the baroclinic component, and stratification component in the lower troposphere
Infrared Absorption by Trace Gases in Atmosphere
Wang Songgao, Zhang Guangshun, Zhu Shunbin
1995, 6(1): 70-75.
With 60 SXR FTIR spectroscopy and variable optical path cell, transmissivity measurements of trace gasses (CO2 and CH4) have been made. The main experimental results and its data processing are descripted. Using FASCODE 2 program, transmissivities of CO2 and CH4 which are under same conditions as experiments have been calculated. And, the calculated results are compared with the experimental results, respectively.
A Study on the Climatic Resources and Regions of Apple Quality
1995, 6(1): 76-82.
The relationships between apple quality and meteorological conditions, and the climatic resources of main apple regions in China are analysed. The climatic regions of apple quality are suggested. The results show that the Loess Plateau in the northwestern China, the western area of Qinling mountains and Gansu-Xinjiang Provinces are the climatic regions of high-good quality apple
A Method of Calculating Deep Soil Temperature
NanQinghong, Sang Xiucheng
1995, 6(1): 83-89.
Based on heat conductive equations, a method of calculating deep soil temperature is developed. The thermal conductivity is calculated by difference method, and monthly averages of deep soil temperature are derived with the technique of moving down initial temperature field layer. In addition, several examples are given. The results are effective.
The Relationship Between Frost Injury, Low Temperature and Population of Ice Nucleation Active Bacteria
Feng Yuxiang, He Weixun, Xia Manqiang
1995, 6(1): 90-94.
The relationship between frost injury, low temperature and population of ice nucleation active bacteria on crop leaves are studied by means of radiation-cabinet. The results indicate that the Logistic equation can show the relationship between frost injury and low temperature only under the conditions of a few or even no ice nucleation active bacteria. But Richards equation can describe well the relationship between these three factors under various conditions of ice nucleation active bacteria. Furthermore, the applications of this relationship to frost injury indexes, frost injury prediction, and frost preventing method are discussed.
The Soil Reflectance Measurement with Short Wave Infrared Spectrum
Zhang Yuxiang, Huang Yibin, Zhang Guangshun
1995, 6(1): 95-100.
Using DG-2 short infrared spectroscopic radiometer the soil reflectances for the short wave infrared window area with various soil moistures are measured. The spectroscopic characteristics are investigated. The results show that the spectroscopic response in about 1.6μm is obvious, and the anticorrelation between the reflectance of soil and the moisture content with that wavelength is clean. The measuring results provide feasibility basis for the choice of short wave infrared channels of remote sensing instruments of meteorological satellite, and this experiment is also useful for processing, analysis and identification of meteorological satellite remote sensing information
Direct Use of Satellite Sounding Radiances in Numerical Weather Prediction
Wang Zonghao
1995, 6(1): 101-108.
The paper described comprehensively that the satellite sounding radiances can be used directly in NWP, not have to be retrieved by use of profiles of temperature and humidity. The roles of variational algorithm for direct use of radiances and the calculation of the adjoint equation are presented. The direct method is very flexible and can in principle be applied to ATOVS’ radiance inversion. And, the some aspects the direct use in operational NWP are also introduced
A Study of Doppler Radar VAD Technique
Tao Zuyu
1995, 6(1): 109-113.
Doppler radar VAD technique can draw the divergence of background wind field from the distribution profile of Doppler velocity with azimuth on a distance circle. But, the distribution of Doppler velocity of a distance circle is unintegral normally. In order to calculate the divergence, the data gaps on the velocity-azimuth profile have to be interpolated artificially, which cause the calculated divergence not objective. According to the simple harmonic distribution of Doppler velocity with azimuth, the symmetric method is proposed to avoid making up the data gaps artificially. In addition, the method of area modification for calculating divergence is proposed.
The Topology for Administrative Area in Satellite Remote Sensing
1995, 6(1): 114-117.
In order to apply the meteorological satellite remote sensing to monitoring crop growth and yield prediction, the local meteorological administration developed a topological method of administrative areas information with the help of micro-computer.
The Response of Precipitation and Temperature in China to ENSO
Lu Duanjun, Zhang Xiangong
1995, 6(1): 118-123.
With an objective and quantitive analysis, the monthly precipitation/temperature data are transformed into percentiles of Gamma/Normal distribution at all stations in the 1951~1990 period. Monthly composites are computed for precipitation/temperature with data covering ten ENSO events. Based on the amplitude and phase of the first harmonic, 18 precipitation regions, 7 temperature regions, 35 response periods of precipitation and 9 response periods of temperature are determind. In North China, the middle and lower basin of Changjiang River, and to the south of Changjiang River, the responses of precipitation to ENSO events are distinct from that in the others. Meanwhile, the amplitude of negative temperature anomaly is the strongest and the duration is the longest in the north-middle part of Northeast China
A Study Weather and Climate Features of Precipitation in May in Yunnan
Yan Huasheng, Lu Yabin, You Weihong, Ju Jianhua
1995, 6(1): 124-128.
The effects of atmosphere general circulation background field and weather climate mechanism on the precipitation in May in Yunnan are studied. The results show that the precipitation in May of Yunnan is regulated by the seasonal variation of atmospheric circulation, the seasonal shift of cloud system from ITCZ in March to May, and by the locations of South Asia high and subtropical high. And it is close related with the interaction between the summer monsoon and the westerly trough, and with the interaction between the cold and warm air.