Current Issue

• Study on Land Surface Parameters over Inhomogeneous Landscape of Dunhuang Area by Using Satellite Data
• MA Yao-ming;LIU Dong-sheng;WANG Jie-min;HUANG Rong-hui;SU Zhong-Bo;GAO Feng
• 2003 Vol. 22 (6): 531-536. 
• Abstract ( ) PDF (835KB) ( )
• For studying on the land surface parameters over inhomogeneous landscape of desertification area,the utilization of satellite remote sensing is indispensable.In this study,methods based on Landsat-7 TM are proposed and tested for deriving the regional land surface parameters over inhomogeneous landscapes of the Dunhuang experimental area.Dunhuang area is selected as a basic experimental area for the Chinese National Key Programme for Developing Basic Sciences:Research on the Formation Mechanism and Prediction Theory of Severe Climate Disaster in China.Three scenes of Landsat TM data used in this study are June 3,August 22,2000 and January 29,2001 in Dunhuang area.Some new concepts about the distributions of surface reflectance,surface temperature,MSAVI and vegetation coverage over inhomogeneous landscape of desertification area are point out in this paper.

• Forming Mechanism of Oasis Environment and Building Countermeasure of Ecological Environment in Arid Area
• HU Yin-qiao;ZUO Hong-chao
• 2003 Vol. 22 (6): 537-544. 
• Abstract ( ) PDF (357KB) ( )
• The build of oasis ecological environment has special important stratagem signification for the sustainable economy development in northwest China region.This paper reviews a series of the research results about the oasis microclimate.Based on the forming mechanism of oasis microclimate and the stability of oasis,we bring forward building of countermeasure the ecological environment in northwest arid area of our country and enhancing the oasis stability and anti-jamming ability.The paper indicate that protecting and building oasis ecological environment should use fully the microclimate characteristics of oasis cold island effect to develop inimitable climate ecology style with the limited water resource and the abundant solar heat resource.The oasis environment build should adopt distinct countermeasure for ecological environment with distinct oasis stability.The ecology build of well-run oasis should develop the ecological agriculture with more drought resistant and temperature-enjoying crops to enhance the efficiency and make the full of use of water resource.The low efficiency oasis should adjust the oasis structure as much as possible,and link the patch oases as unit unity and try hard to minish the clothesline effect.The countermeasure of ecological environment build for the degenerate oasis should rehabilitate the ecosystem under the condition of enough supplying the water resource,and should restrict the exploitation of groundwater,the development of the agriculture and the animal husbandry to restrain more degeneration of the ecosystem.

• Observational Result of Dust Emission Rate over Sand Surface of Gobi Desert During Dust Storm
• SHEN Zhi-bao;SHEN Yan-bo;DU Ming-yuan;WANG Wan-fu
• 2003 Vol. 22 (6): 545-550. 
• Abstract ( ) PDF (257KB) ( )
• Using the dust particle concentration data measured by portable dust particle counter,the dust emission rate over the sand surface of Gobi desert in Dunhuang was estimated.Two dust events occurred on April 8 and 13,2002 were selected.Each event was divided into the dust storm stage(DCI≥0.4) and 2 blowing dust stages(0.4>DCI≥0.2) before and after dust storm stage.For estimating the dust emission rate by use of the dust particle concentration data,we assumed that the vertical flux of dust particles through 2 m high level is equal to that emitted from the surface.The estimated dust emission rate of both cases(April 8 and 13) are as follows:0.94×10 ^-8 and 1.03×10 ^-8 kg·m ^-2·s ^-1 during the blowing dust stage;1.18×10 ^-8 and 1.89×10 ^-8 kg·m ^-2·s ^-1 during dust storm stage;the mean dust emission rate during whole dust event are 1.00×10 ^-8 and 1.58×10 ^-8 kg·m ^-2·s ^-1,respectively;and the maximum emission rate on April 13 was 2.77×10 ^-8 kg·m ^-2·s ^-1.The relationship between dust emission rate and frictional velocity was analyzed too.

• Measurement of Column Cloud Liquid Water Content by Airborne Upward-Looking Microwave Radiometer(I):Instrument and Its Calibration
• LEI Heng-chi;WEI Chong;SHEN Zhi-lai;ZHANG Xiao-qing;JIN De-zhen;GU Shu-fang;LI Mao-lun;ZHANG Jing-hong
• 2003 Vol. 22 (6): 551-557. 
• Abstract ( ) PDF (308KB) ( )
• The pre-scheme,design and performance of an airborne upward-looking microwave radiometerto measure column suppercooled cloud liquid water content as well as total column cloud liquid water content are introduced.The pre-scheme suggests the feasibility of a single frequency radiometer for this purpose and focuses some technical difficulties of making suchinstrument,that are important references in design and performance of the instrument.The test methods of instrumental sensibility and its results are shown.The tests both in laboratory and on the airplane suggest that under certain conditions the tested sensibility can be less than or equal to 0.2K.In addition,some feasible methods of instrumental calibration are introduced in detail,and their applicable condition as well as their uncertainty are discussed.

• Distribution Characteristic of Severe Convective Thunderstorm Cloud over Qinghai-Xizang Plateau
• ZHANG Hong-fa;GUO San-gang;ZHANG Yi-jun;CHENG Guo-dong;SHI Yun-qiang;PUBU Zhouma;HOU Zheng-jun
• 2003 Vol. 22 (6): 558-564. 
• Abstract ( ) PDF (1071KB) ( )
• Using the thunderstorm data over Qinghai-Xizang Plateau in summer(May to September) from 1950 to 2000,especially the surface and upper weather data,radar echo data in field experiment observation over Qinghai-Xizang Plateau in recent 50 years,the change characteristics of convective thunderstorm distribution along Qinghai-Xizang Railway,diurnal variation and life cycle of severe thunderstorm over Qinghai-Xizang Plateau were analyzed.The results show that the severe thunderstorm weather in summer along Qinghai-Xizang Railway increased from north to south,the annual mean thunderstorm numbers reach 90,and thunderstorm in May~September accounts for 97% in whole year.The occurring time of thunderstorm over Qinghai-Xizang Plateau is mainly at 15:00~22:00(BLT) and decaying from north to south.The maintain of life cycle of severe convective thunderstorm activity over Qinghai-Xizang Plateau with ≤1 h makes up over 70%,that of 1~2 h 20%,and 2 h less than 10%.

• Comparison Study of Spatial Interpolation Methods of Air Temperature over Qinghai-Xizang Plateau
• LI Xin;CHENG Guo-dong;LU Ling
• 2003 Vol. 22 (6): 565-573. 
• Abstract ( ) PDF (1938KB) ( )
• The spatial interpolation methods of inverse distance weight,trend surface,Kriging,Co-kriging and combined method are utilized for the comparison study on spatial interpolation of January mean air temperatures from 1961 to 1990 in the Qinghai-Xizang Plateau(QXP).The results of the former four methods display a nearly similar spatial structure.Moreover,the center of low temperature in northwestern QXP can not be revealed due to uneven spatial distribution of meteorological stations and limited obsevations.In the combined method,monthly mean air temperature is divided into structural and stochastic components,and,with the help of Digital Elevation Model(DEM),the structural component is simulated by the lapse rate of different latitude and altitude zones in the QXP,the stochastic component is treated by the Kriging method.The results of combined method correctly represent spatial distribution of monthly mean air temperatures in the QXP.Its errors are far less than ordinary Kriging method that depends only on samples.Furthermore,the errors have been averaged,and they are evenly distributed in the study area.The comparing study of these interpolation methods on the monthly mean air temperature in the QXP indicates that the best spatial interpolation method does not exist,the best interpolation method only exist in given conditions.The best results of data interpolation can only be achieved by exploratory spatial data analysis and various experiments.The interpolation results showed that spatial distribution of monthly mean air temperatures in the QXP is controlled by altitudinal and latitudinal zonations,displaying a structure of high temperature in eastern and southern parts and low temperature in western and northern parts.The January mean air temperature in the QXP is lower than -13℃ and increases southeastward.The biggest center of low temperature is located in northwestern QXP north of 34°N and west of 93°E,with January mean air temperature lower than -16℃ and the lowest interpolated value of -25℃;another lower temperature area is in Qilian Mountains.Secondary level low temperature centers with smaller areal extent have been found in the regions around Wudaoliang,Tuotuohe and Maduo in the interior of the QXP,with January mean air temperature lower than -15℃.High temperature center of January is located in southeastern QXP,the high temperature ridge extends northward to Changdu and westward to Lhasa and Xigaza along the 29°N(Yaluzangbu River).The air temperature increases southeastward from -3℃ to 6℃.

• Improvement Study on Cloud Drift Wind Data to REM Mesoscale Simulation
• HUANG Yan-bin;LEI Heng-chi;GUO Xue-liang;YANG You-ling;WANG Zhen-hui;WANG Zhi-bang
• 2003 Vol. 22 (6): 574-582. 
• Abstract ( ) PDF (487KB) ( )
• The wind field data-cloud drift wind data were introduced by GMS5 stationary satellite cloud image,which have been used to improve the initial wind field of limited-area model of REM.Two rain processes over West China on 27,28 July 2001 and three rainfall processes over East China on 16,18,19 August 2001 have been simulated.Both the control test experiment and sensitivity test experiment have been performed through the improvement of initial wind fields.The results show that the cloud drift wind data introduced by satellite cloud image can improve the initial wind fields of mesoscale numerical simulation,rise the simulation precision,and capture some meso-and small-scale systems that are usually omited because of the observation station sparseness.

• Analyses on Vertical Microphysical Characteristics of Autumn Stratiform Cloud in Lanzhou Region
• LI Zhao-rong;LI Rong-qing;LI Bao-zi
• 2003 Vol. 22 (6): 583-589. 
• Abstract ( ) PDF (313KB) ( )
• The vertically sounding data of the stratiform cloud over Zhongchuan Air Port of Gansu in 5 weather processes in September and October 2001 measured by the airborne PMS probes and hygrothermoscope have been used.The data cover microphysical characteristics of autumn stratiform clouds such as Cs-As-Ns and Ac-Sc,cloud particle density,diameter,liquid water concentration and relative temperature.The cloud particle spectra were fitted by using a N order Γ type function and the optimum parameters were picked out.It is pointed out that the position of inversion layer corresponding to the 0℃ layer and the inversion intensity have obvious influence on the distribution of cloud microphysical characteristics and form of precipitation.

• Satellite Image Analysis on Dust Storm Process in Ningxia on April 6,2001
• HU Wen-dong;GAO Xiao-qing
• 2003 Vol. 22 (6): 590-596. 
• Abstract ( ) PDF (365KB) ( )
• Combining with conventional synoptic information,and using the GMS-5 geostationary satellite data,the synoptic system,physical mechanics,developing characteristics and topographic effect of dust storm event in Ningxia happened on April 6,2001 have been analyzed.The results are as follows:(1) This event can be seen clearly on the satellite images,the movement of the leading edge can be easily identified.(2) This case is a combined result of strong northwest wind in higher altitude and a quick moving surface cold front.(3) The dynamical and thermal effects can be identified on the images,and their roles change with time.(4) The topographic effect is a very important fact in the evolution of dust storm.These are of important significance in the prediction of dust storm.

• The Meso-Scale Diagnostic Study on a Heavy Rain in Southwest Yunnan Autumn
• DUAN Xu;XU Mei-ling;SUN Ji-hua;YANG Ming-zhu
• 2003 Vol. 22 (6): 597-601. 
• Abstract ( ) PDF (1078KB) ( )
• By using the diagnostic methods of large-scale circulation and the meso-scale band-pass filter,the mechanism of the storm rainfall occurring in the southwest region of Yunnan province on 25 October 2001 are analysied in this paper.The results show that the meso-scale weather system is the direct cause of the storm rainfall occurring in the southwest flow outside the subtropical high;The large-scale circulation provide an abundance of vapour source for storm rainfall occurring,but the meso-scale weather system act as an important factor in which the vapour has the strong convergence and upward transport,and make the mid-lower troposphere to get at quasi-saturation state.

• Relationships between South Asian High and Summer Rainfall in North China
• HUANG Ying;QIAN Yong-fu
• 2003 Vol. 22 (6): 602-607. 
• Abstract ( ) PDF (346KB) ( )
• Based on the monthly rainfall data at 17 stations in North China from 1958 to 1997,the correlations between the South Asian High(SAH) in the area of 30°W~180°E,0°~60°N and the summer rainfall in North China are analyzed.The atmospheric circulation at 100 hPa,the stream function and the velocity potential at different heights are composed and discussed in order to depict the mechanism of the influence of the South Asian High on precipitation in North China.The results show that the summer rainfall in North China and the South Asian High is negative correlated,that is to say,when the SAH is stronger,the rainfall will be less in the North China;when the SAH is located more westward,the heavier rainfall will be occur,and vice versa.

• Compution and Characteristic of a Model Atmospheric Reference State
• GU Xu-zan
• 2003 Vol. 22 (6): 608-612. 
• Abstract ( ) PDF (231KB) ( )
• Two set of scientific data about the atmospheric reference state of the T106L19 model in a limited area(15°~60°N,70°~140°E) are given,the one is in winter and the other is in summer,and some physical features of them are studied.The results show that their air entropies roughly respectively accord with a mathematical probability density function of the Γ-distribution,and there always is a stable inversion layer in their low level.But they will be changing regularly with the seasons and the atmosphere general circulation.

• Multi-Band Remote Sensing Study on Aerosol Optical Depth in Tengger Desert
• ZHANG Wen-yu;XIN Jin-yuan;YUAN Jiu-yi;LIU Li-chao
• 2003 Vol. 22 (6): 613-617. 
• Abstract ( ) PDF (211KB) ( )
• Based on the data of surface multi-band(450~900 nm) solar radiant flux observed at Shapotou station of Tengger desert during April~September 2001,the calibration of instrument,the changes of aerosol depth in different wavelengths and its changing rule were discussed.The results show that the calibration of instrument is reliable to the special photometer.In the different weather condition,the changes of aerosol optical depth in the Tengger desert area exist obvious different,namely the total optical depth is high and temporal-spatial varication is significant.But under the same weather condition,the changing rules of different wavelengths were nearly consistent.There are different aerosol size distributions in the weather condition.

• Study on Mixed Forecast Model of Neural Network of Monthly Precipitation
• JIN Long;LUO Ying;WANG Ye-hong;LI Yong-hua
• 2003 Vol. 22 (6): 618-623. 
• Abstract ( ) PDF (244KB) ( )
• Based on itself-period change of predictand characterized by mean generating function method,500 hPa monthly mean height field and the predictor of monthly mean SST,a new short-term forecast pattern is established by the artficial neural.June rainfall in north-,center-and south-parts of Guangxi,respectively,as predicative object is carried out predicative experiment.The results show that the new method has more better prediction ability and physical foundation than the regression prediction patterns of mean genrating function,500 hPa height field and SST.

• Activities of Bay of Bengal Monsoon and Beginning Date of Rain Season in Yunnan
• YAN Hong-ming;XIAO Zi-niu;WANG Ling
• 2003 Vol. 22 (6): 624-630. 
• Abstract ( ) PDF (409KB) ( )
• Based on pentad and monthly mean wind and specific humidity data of NCEP from 1958 to 1997 and precipitation data of 32 stations in Yunnan,the activities of the Bay of Bengal(BB) monsoon and the correlation relation between BB monsoon and precipitation in early summer of Yunnan have been studied,and we got some interesting evidences.First,on 850 hPa,comparing with SCS and Arab zonal wind,the appearing of BB zonal wind is the earliest and the its variation is similar to that of SCS zonal wind during summer monsoon.Second,the onset date of southern BB summer monsoon is 6 pentads in April and that of northern BB summer monsoon is 3 pentads in May,and it is the earliest in the onset of Asian summer monsoon.The onset of southern BB summer monsoon is earlier than onset of northern BB summer monsoon.Last,May precipitation in Yunnan increases while the onset of BB summer monsoon islaterabout 2~3 pentads,whereas more and less May precipitation in Yunnan is closely relative to the activities of cold air at mid-latitude,it may increases or decreases while the onset of BB summer monsoon is early or later about 1 pentad.

• Distribution Characteristic of Surface Wind Field over Wentouzi Aera of Liaodong Bay
• MA Yan-jun;YANG Hong-bin;ZHANG Yun-hai
• 2003 Vol. 22 (6): 631-636. 
• Abstract ( ) PDF (1502KB) ( )
• Using the wind field diagnostic model and atmospheric diffusion experimental data in winter and summer in Wentouzi area of Liaodong Bay,the distribution characteristic of horizontal wind field at nuclear power station have been analyzed.The result show that there are mainly three patterns for distribution of horizontal wind fields at this area in winter,they are:(1) southerly wind pattern,(2) northerly wind one and(3) the local wind one,the nuclear power station is between high and low pressures,or in a homogeneous pressure field,the mountain-valley wind flowed obviously,this kind of surface wind field of this aera is favourable to the confusion.There are mainly four patterns for distribution of horizontal wind field at this area in summer,they are:(1) sountherly wind patten,(2) sea-land wind one,(3) shear wind one and(4) northerly wind one.

• Parameter Optimization of Heavy Rain Intensity Formula Based on Genetic Algorithm
• LI Zuo-yong;PENG Li-hong
• 2003 Vol. 22 (6): 637-639. 
• Abstract ( ) PDF (455KB) ( )
• Genetic Algorithm(GA) is an effective method for parameter optimization of model.Genetic algorithm was applied to optimize the parameters of storm rainfall intensity formulae of different repeat periods in Beijing suburban.Comparisons of optimum results between the genetic algorithm method and the traditional regression method as well as optimum seeking method were performed.The calculated results show that the use of GA method estimation precisions of parameters in the storm rainfall intensity formula is highter than that of traditional regression and optimum seeking methods.The method has the objectivity,simplicity and effectiveness.

• Contribution of Multi-Hotspring Regions over Qinghai-Xizang Plateau to Air Temperature Field
• JIANG Hao;TANG Mao-cang;GAO Xiao-qing
• 2003 Vol. 22 (6): 640-642. 
• Abstract ( ) PDF (150KB) ( )
• When the background field of surface air temperature field over Qinghai-Xizang Plateau is removed by linear regression method,it is found that the Yarlungzangbo River and west Sichuan plateau are two high temperature regions,and they and the multi-hotspring region over Qinghai-Xizang Plateau coincide.The calculation based on surface energy balance equationand the geothermic release parameter measured in Yangbajing area show that the geothermal energy release of the multi-hotspring regions can make 1~2℃ temperature increment in whole year.

• Winter and Spring Destructive Earthquakes in Taiwan and Its Correlation with Distribution of Summer Precipitation in Mainland
• ZHAO Hong-yan;TANG Mao-cang;ZHANG Li-ping
• 2003 Vol. 22 (6): 643-645. 
• Abstract ( ) PDF (148KB) ( )
• Based on the data of precipitation and earthquake from 1951 to 2001,the relationship between summer precipitation in mainland and the destructive earthquake in Taiwan and western China-Mongolia are analyzed.The conclusion obtained are as follows:When the destructive earthquakes occurred during last year(October to next April),the Yangtze River and Jiangnan area will not be wet(less precipitation) in this year summer.When the destructive earthquakes(≥6.9) occurred both in Taiwan and western China-Mongolia,a flood area will be appeared over the regions north to the Yangtze River.

• Development of Automatic Meteorological Station Suitable for Cold and Arid Areas and 10 Element Collecting
• ZHAO Ai-guo;NIE Yan-jiang;HOU Xu-hong;LI Yong;LI Hong
• 2003 Vol. 22 (6): 646-649. 
• Abstract ( ) PDF (181KB) ( )
• Taking the DT500 data collector as the central control system in the weather station system,the meteorological station system of 10 parameter's automatic collecting,including the wind velocity,air humidity,ground temperature,air pressure,sunlight,evaporation,radiation,precipitation,are developed.This system can work well in execrable environment,i.e.,severe cold,high humidity,strong wind,dusty and unmanned area.