Current Issue

• Study on HCl Distribution and Its Relation to Ozone over Qinghai-Xizang Plateau Using HALOE Data
• CHEN Yue-juan;SHI Chun-hua
• 2005 Vol. 24 (1): 1-8. 
• Abstract ( ) PDF (1222KB) ( )
• The hydrochloric acid data observed by HALOE in UARS satellite from 1992 to 2002 are used to analyze its distribution and variation in stratosphere over Qinghai-Xizang Plateau. Comparing with the distribution and variation of Ozone over Qinghai-Xizang Plateau, we probed the possible influence of hydrochloric acidon Ozone over Qinghai-Xizang Plateau. The results show that the HCl mixing ratio increased with altitudes in stratosphere over Qinghai-Xizang Plateau. In the levels near 100 hPa and below, the HCl mixing ratio is less than 10^-10; in the layers from 10 hPa to 0.1 hPa, it reached 2~3×10^-9 in the order of magnitudes. There is obvious differences between HCl mixing ratio over Qinghai-Xizang Plateau and those over the same latitudes.In summer, the HCl mixing ratio nearthe 100 hPaover Qinghai-Xizang Plateau is less than that averaged in the same latitudes, but in the layers from 25to 5 hPa, it is lager than that averaged in the same latitudes.The situation in winter is nearly opposite to that in summer. The correlation is obvious between the distribution and variation of HCl and O₃, and it changes with altitudes. In the layers from 25to 5 hPa,there is obviously anticorrelation between the variation of HCl and O₃. In the layers from 30 to 70 hPa, the correlation is not so obvious, while in the layer near 100 hPa, there is obviously positive correlation. Since the anticorrelation is the best in the layers from 25 to 6 hPa(about 25 to 36km) where the O₃ mixing ratio is larger, the hydrochloric acid is more important for causing the ozone depletion.

• Simulation of Land-Atmosphere Exchange Processes at Amdo and Gaize Stations over Qinghai-Xizang Plateau
• CHEN Hai-shan;SUN Zhao-bo
• 2005 Vol. 24 (1): 9-15. 
• Abstract ( ) PDF (1144KB) ( )
• Using the field observational data during GAME-Tibet 1998 IOPs, the land-atmosphere exchange processes at Amdo and Gaize Sations of Qinghai-Xizang Plateau are simulated by a comprehensive land surface model(CLSM). In which Amdo and Gaize Stations have the grassland and bare typical underlying surfaces respectively. The contrasts of the land-atmosphere exchange processes observed and simulated by the single point column model suggest that the CLSM has the capability to give a reasonable simulated result on the basic physical process of the land surface and the exchange between the land and the atmosphere in both sites.

• Variation Features of Soil Temperature and Moisture Content at Dry-and Alpine-Desertification Surface and Their Interaction Analyse
• XIE Zhi-qing;LIU Jing-miao;DING Yu-guo;DU Yin
• 2005 Vol. 24 (1): 16-22. 
• Abstract ( ) PDF (800KB) ( )
• On the basis of observed data, the spatial-temporal variation characteristics of soil temperature and its effects on soil water movement in two kinds of underlying surfaces of Heihe, Gaize and Shiquanhe are studied. In which the Heihe River valley is as a representative of the typical dry desertification underlying surfaces; and Gaize and Shiquanhe Stations over Qinghai-Xizang Plateau, one of alpine desertificat underlying surfaces. The results show that there exit the several periodic variations for soil temperature at different depths ranging from six to twenty four days in Heihe region, and from nine to thirty days in Gaize and Shiquanhe region. It also shows that the gradient of soil temperature affects the soil water content movement more greaterly in summer than in winter.

• Implement of Non-Linear Iteration Time Integral Scheme in IAP AGCM-Ⅱ Model and Its Simulation
• ZHENG Hong-lian;ZHANG Ming
• 2005 Vol. 24 (1): 23-27. 
• Abstract ( ) PDF (993KB) ( )
• The non-linear iteration time integral scheme is used in the dynamical framework of original IAP A GCM-Ⅱ model and it is verified by Rossby-Hauwitz wave. The results show that the scheme can carry out long integration time with well stability.In order to further test its simulation ability, two three year-long integral simulations of the model have been conduted, in which one is with the non-linear iteration time integral scheme;but the other is without. The simulations show that the model with the scheme has the better results of simulating precipitation, especially in East Asia region.

• Simulation Experiments of Summer Climate and Change in East Asian Using MM5BATS Regional Climate Model
• TANG Jian-ping;ZHAO Ming;SU Bing-kai;ZHAO De-min
• 2005 Vol. 24 (1): 28-37. 
• Abstract ( ) PDF (1759KB) ( )
• This paper presents a 6-year (1995-2000) summer climate simulation using the MM5V3 model coupled with the BATS1e land surface model and the NCAR RegCM2 regional climate model over East Asia. The simulation results were compared with the observation. The results show that:(1) these two regional climate models could simulate the 6-year summer mean circulation, temperature and sea level pressure. The simulation result of MM5BATS is better than the RegCM2's. (2) MM5BATS could better simulate the distribution of 6-year summer mean precipitation rate. The RegCM2 overestimated the precipitation rate. (3) MM5BATS could simulate the change of summer circulation in 1997 and 1998, and the distribution of precipitation. And RegCM2 overestimated the summer precipitation in 1997 and 1998. The simulation results show that it is necessary to use the next generation model for regional climate simulation.

• Information Entropy Analysis on Turbulent Temperature Series in the Atmospheric Boundary-Layer
• WANG Jing-ye;FU Zun-tao;ZHANG Lin;LIU Shi-da
• 2005 Vol. 24 (1): 38-42. 
• Abstract ( ) PDF (283KB) ( )
• The turbulent temperature time series in the atmospheric boundary layer close to ground surface are applied to analyze the characteristics of turbulence in this paper. And comparison between stable stratification and unstable stratification is shown with the method of power spectrum analysis and information entropy analyses. It is found that the information entropy and exponent of power spectrum are two powerful indexes to distinguish the atmospheric turbulence in boundary layer and the explanation for difference between stable and unstable stratifications is presented.

• Energy Transfer of Near Surface Layer and Micrometeorology Characteristics in Bailuhe Area of Qinghai-Xizang Plateau
• QIAN Ze-yu;HU Ze-yong;DU Ping;ZHANG Yan-wu
• 2005 Vol. 24 (1): 43-48. 
• Abstract ( ) PDF (1050KB) ( )
• Using the observed data at automatic weather station in Beiluhe area from 30 May to 24 June 2002, the characteristics of energy balance of surface, heating flux of surface, the sensible and latent heat, surface albedo, bulk transfer coefficients of momentum and heating are analyzed. Some new concepts about the characteristics of both the flux densities and micrometeorology in the surface layer of the atmosphere in the Beiluhe area of Qinghai-Xizang Plateau are obtained.

• The Effect of Multi-Scale Waves in Torrential RainProcess in Wuhan in July 1998 and Its Coherence
• WEI Feng-ying;ZHU Fu-kang;XIE Yu
• 2005 Vol. 24 (1): 49-55. 
• Abstract ( ) PDF (419KB) ( )
• The effect of muli-scale waves on torrential rain process over the mid-and-lower reaches of Changjiang River in the last ten-day periods of July 1998 was studied by Morlet complex wavelet transformation, and its coherence was investigated with the cross spectrum between the multi-scale waves. The results show that the torrential rain process is a process of the accumulation and release on the energy of meso-β scale system, and the meso-α scale system had an interference effect on the meso-β system in a shorter period.

• Derivation of A New Diagnostic Equation of Stream Function and Application to Severe Rainstorm in Changjiang and Huai River Regions
• ZHAI Wu-quan;ZHENG Lan-zhi;SHI Chun-e;LI Guo-jie;ZHAO Jian-yong
• 2005 Vol. 24 (1): 56-61. 
• Abstract ( ) PDF (288KB) ( )
• A new stream function diagnostic equation, which is suitable for describing the transverse circulation in frontal zone (Y-P cross-section) is derived, the physical meaning and effect of its various force functions in the diagnostic equation are analyzed, and it is validated by the intensive observational data in HUBEX. Based on the diagnostic equation, we designed a integrated analysis chart on a 2-D cross-section that can describe the character of vertical circulation in frontal zone, and concluding three kinds of concept models on vertical circulation, which can give better directions to the forecast of the storm rainfall in flood season of Changjiang and Huai River regions.

• The Effects of Vertical Distribution of the Lower Level Flow on Precipitation Location
• SUN Ji-song
• 2005 Vol. 24 (1): 62-69. 
• Abstract ( ) PDF (1109KB) ( )
• The dynamical effects of the topography on air flows with different vertical distributing have been studied. If a mountain is upright to air flow, the results are as follows:When lower level wind is stronger than upper wind, the divergence motion and wind shear come into being, and eddy will be enhanced, so the precipitation obviously amplitudes against to windward slope. To leeward slope, the situation is opposite. However, when upper wind is stronger than lower, there will be diverged motion on windward slope and eddy will be enhanced on leeward slope. The viewpoints are successfully utilized to explain the different precipitation distributing which happened in North China.

• The Application of Three-Dimensional Variational Assimilation in A η-Coordinate Mesoscale Model
• ZHANG Wan-cheng;XIAO Zi-niu;ZHENG Jian-meng
• 2005 Vol. 24 (1): 70-76. 
• Abstract ( ) PDF (1423KB) ( )
• The three dimensional variational assimilation is conducted in a η-coordinate mesoscale model. The initial fields of the model before and after the assimilation are compared in these experiments. The rainfall in the starting period of rainy season of Yunnan from 00:00 on 10 May to 00:00 on 15 May 2002 were simulated by the numerical model. The results show that the object function of the three dimensional variational assimilation is quite fast in the convergence. In the predicting of both the severe rainfall centers and rain area distributions,the model forecast performances of model with the variational assimilation scheme are better than those without one.

• Verification and Reproduction of the New Understanding for Mechanism of Hail Cloud
• TIAN Li-qing;XU Huan-bin;WANG Ang-sheng
• 2005 Vol. 24 (1): 77-83. 
• Abstract ( ) PDF (1932KB) ( )
• Recent numerical simulations show that there are cave channels (CC) in hail clouds, which depend on the interaction between the stream and hydrometeor field; one end of the CC connects with embryo formation area, and the other with large stone formation area; while moving round the zero line of horizontal wind, particles concentrates to the CC, result in the accumulation of particles can be found in a whole. Target area should include the CC, which locates at the flank of the main updraft and closely below the zero line of horizontal wind and so on. In this paper, the above were verified by Doppler radar observations and be reproduced on the basis of some reliable researchos.

• Airborne Observation for Microphysical Structure of Precipitation System of Stratiform Cloud in Hebei Provice
• YANG Wen-xia;NIU Sheng-jie;WEI Jun-guo;SUN Yu-wen
• 2005 Vol. 24 (1): 84-90. 
• Abstract ( ) PDF (1189KB) ( )
• Based on integrated analysis of the cloud data obtained by the particle measuring system(PMS)in 4 cases in Hebei Province, it is found that the stratiform clouds of precipitation in spring are inhomogeneous, in which there exist cloud bands of severe precipitation.The inversion is detected at twice about the height of 2000 m aircraft ascending and descending on 25 May 1991. There is a peak value of liquid water content(LWC) below the top of the inversion layer. The vertical distributions of the ice crystal size, ice water content(IWC), ice crystal concentration and LWC on 20 June 1992 are analysized. The seeding condition criteria and operation indexes in cold stratiform clouds presented by Tao Shuwang et al^[13] are used to judge the seedability in cloud of 2 cases. It is found that the seedable clouds are about 1/2 of total clouds, sometimes there are a large scale highly seedable clouds.

• Test on Monitoring Meso-and Micro-Scale Precipitation in Beijing Using GPS Data and Satellite Image
• CAO Yun-chang;FANG Zong-yi;LI Cheng-cai;WANG Ying-chun
• 2005 Vol. 24 (1): 91-96. 
• Abstract ( ) PDF (1836KB) ( )
• The precipitable water (PW) of high temporal resolution obtained by ground-based GPS remote sensing provides a way for analying and forecasting the evolution of mesoscale and microscale systems. Using the PW data in Beijing in June~August 2000 retrieved GPS/VAPOR Experiment, combining GMS5 images with T106 analysis data, the distribution of PW in Beijing summer and heavy rain storm cases in July 3~5 are studied. The results showed that GPS PW changes and the development and maintenance of cloud are to produce the condition of severe precipitation. the more and less precipitation is related to their increasing amplitude, duration and sustained level. The change of PW is identical with IR cloud image displying the change of meso-and micro-scale systems. The moving of PW is closely related to the precipitation of observational station. When the precipitation of observational station quickly increase and the distribution of PW synchronously extend to the observational station, the precipitation of station quickly increase as well. GPS PW is regarded as an index of short-range precipitation prediction at station.

• Retrieval of Aerosol Optical Depth over Lanzhou Area Using MODIS Data
• ZHAO Xiu-juan;CHEN Chang-he;ZHANG Wu;GUO Ni
• 2005 Vol. 24 (1): 97-103. 
• Abstract ( ) PDF (821KB) ( )
• A test of sensitivity to the surface reflectance and aerosol optical depth (AOD) were made for the planetary albedo of three Channel of MODIS (blue, red and mid-infrared). The surface reflectance at these three Channel over Lanzhou and its surrounding areas were inversed with MODIS data and used to verify the relationships among them reported by kaufman. The results are consistent with Kaufman's.Based on the verification, we use the blue channel to retrieve the AOD over Lanzhou city and its surrounding areas in the range of nearly 1×10⁴ km² by 6S model. The result shows that the distribution of the retrieved AOD is reasonable.

• Relationship between Sand-Dust Storm in Northern China in April and Westerly Circulation
• ZHONG Hai-ling;LI Dong-liang
• 2005 Vol. 24 (1): 104-111. 
• Abstract ( ) PDF (2087KB) ( )
• Data of monthly sand-dust storm days at 185 meteorology observation stations, China from their foundation of station to 2000 were selected, the climatic characteristics of sand-dust storm in Northern China in April in recent 40 years and its response to the abnormal of westerly circulation were analyzed.The characteristics of general circulation in spring and the months preceding inmore and less sand-dust storm years are compared. The results show that according to the EOF analyses, there exist the in phase pattern in the entire region and out-of-phase pattern in east-and west-parts of the region for the spatial distribution of the sand-dust storm day variation. The total trend of sand-dust storm daysin Northern China is decreasing in recent 40 years. In more sand-dust storm years, the meridionality of Eurasian general circulation is stronger, the location of Eurasian general circulation is stronger, the location of zonal wind over high altitude in Northern China is north-toward and its intensity is weaker, and vice versa. The farther researches indicate that the characteristics of general circulation and zonal wind component of high altitude in last month is regarded as the indicator to forecast the days of sand-dust storm in the next month.

• Activity of Geothermal Vortex in Huai-River Flood Season and Discussion of Forecast Method
• ZHANG Yong-jun;TANG Mao-cang;LI Dong-liang
• 2005 Vol. 24 (1): 112-116. 
• Abstract ( ) PDF (1806KB) ( )
• By analyzing the evolution of the ground temperature fields in 2003, the main reason for the Huai River flood in flood season of 2003 is discussed. The result shows that there are two necessary conditions in flood period of Huai River drainage area:The active geothermal vortex in Huai River drainage area last winter and the strong earthquake (M_s)≥6.5) happened in central part of north Burma or western China.

• A Study of Qinghai Grassland Productivity Using NOAA/AVHRR
• WANG Jiang-shan;YIN Qing-jun;YANG Ying-lian
• 2005 Vol. 24 (1): 117-123. 
• Abstract ( ) PDF (1576KB) ( )
• Qinghai province is located in Qinghai-Xizang Plateau and ecological environment is fragile. In recent 20 years, because of the combined influence of climate change and human activities, the great change of ecological environment, especially grassland resources, have taken place. By using Pathfinder Data Sets of NDVI from 1981 to 1999 provided by EROS data center, on the basis of studying the principles and methods of dynamic change of grassland productivity, the spatial and temporal characteristics of grassland productivity change and difference between different places in the latest 20 years were analyzed.

• Interpretation of Snow-Covered Ground Objects Using RADARSAT Image
• XU Zong-bao;LIANG Tian-gang;CHEN Quan-gong;DONG An-xiang
• 2005 Vol. 24 (1): 124-128. 
• Abstract ( ) PDF (420KB) ( )
• In this paper, all 5 counties of Aletai, Buerjin, Jimunai, Habahe and Fuhai in Aletai region, Northern Xinjiang are selected as typical study area. By use of Canada RADARSAT data, the geometric correction and fundamental principles of radar remote sensing are studied. And the image interpretation is comparatively analyzed between the rectified geo-referenced radar image and images processed by brightness adjustment, edge enhancement, image enhancement, speckle suppressionand texture analysis methods. The interpretation indicators of radar image are established for the important objects closelyrelated to activities of relief snow disaster, such as cropland, river, traffic, residentialareas and etc. Results showed that microwave radar remote sensing can avoid the difficulties in monitoring of snow disaster using visible and near-infrared remote sensing data, which can provides scientific informationfor decision making in snow disaster areas.