Current Issue

• Analyses on Changes of Surface Temperature over Qinghai-Xizang Plateau
• LI Dong-liang;ZHONG Hai-ling;WU Qing-bai;ZHANG Yong-jun;HOU Yi-ling;TANG Mao-cang
• 2005 Vol. 24 (3): 291-298. 
• Abstract ( ) PDF (1942KB) ( )
• The basic climate characteristics of winter,summer and annual mean surface temperatures were analyzed by using 86 stations over the Qinghai-Xizang Plateau(QXP) during the period from beginning to 2001, and the spatial anomaly structure and time evolution tendency have been systematically diagnosed by principal component analysis, a periodic function and a random function and power spectral analysis methods. The result shows that the surface temperature is a function of elevation above sea level and latitude. The higher the elevation above sea level and latitudes are, the lower the surface temperature is. The annual mean surface temperature is 14.9℃ in Chayü of the Yaluzangbu River, and the maximum value of surface temperature in summer is 23.0℃ in Germu of Chaidamu Basin. The minimum value of annual mean surface temperature in center of Plateau is -0.2, in winter,-14.2~-15.8℃, in summer, 9.8℃ at Qingshuihe, The first loading vector of surface temperature anomaly over Plateau is with the same sign in whole Plateau. The second loading vectors have differences in the north and south. The variation of the first principal component had an obvious warming trend in the last 30 years, but the second principal components were weak cooling trend, and there are quasi-three to six year periodic oscillations for the interannual variation. The rates of linear temperature rising along north-and-south sections of railways are 0.42~0.58℃/10a, and the center is 0.32~0.39℃/10a.

• Studies on Nonlinear Oscillation Evolution Law of Local Temperature along Qinghai-Xizang Railway
• WANG Wen;CHEN Xiao-min;LI Dong-liang
• 2005 Vol. 24 (3): 299-303. 
• Abstract ( ) PDF (213KB) ( )
• The nonlinear oscillation equation describing local temperature were applied to study the evolution law of local temperature at 9 stations along Qinghai-Xizang Railway, the specific equation was obtained form the retrieving theory and the each year temperature data during 1966 to 1997. With taking no account of the external forcing condition, according to the classical nonlinear oscillation theory, the temperature evolution law at 9 stations along Qinghai-Xizang Railway was studied. The results indicate that the local-air systems at 9 stations along Qinghai-Xizang Railway are obvious nonlinear systems, and their inherent periods are form 3 to 6 years. The local temperature amplitude always decreases with time, and their average forecasting accuracy is 75.4%, which indicate that the equations have better forecasting ability.

• The Prediction and Probability Estimation of Mean Maximum and Minimum Air Temperature along Qinghai-Xizang Railway
• WANG Wen;LI Dong-liang;CHENG Guo-dong
• 2005 Vol. 24 (3): 304-310. 
• Abstract ( ) PDF (1330KB) ( )
• The mean maximum and minimum temperature series are constructed utilizing the observations along Qinghai-Xizang railway seven stations from 1955 to 2000. It showed that the minimum temperature had been in lower period before 1975, and the lowest one which occurred in 1960's was 1.4℃ lower than normal; it was getting warmer after 1975 and it was 1.4℃ higher than normal in 2000. The maximum temperature was 0.1℃ warmer in 1960's than normal and 0.2℃ lower in 1970's and 1980's than normal, but it warmed up again since 1990's and 0.8℃ over the average in 2000. It is obviously that the temperature increased significantly during the period of 1955 to 2000, particularly the minimum temperature. The variation of future sunspot cycle length(SCL) was predicted by 5 significant cycle periods of the SCL in recent 1000 years, 41, 58, 76, 90 and 200 years, and the Gram-Schmidt method of mean generating function, the result showed that the SCL in the 21^th century will be 1 year longer than in the 20^th century, it will reach the longest cycle of 12.4 years in 2055 and turn to short period of 10.6 years in 2068. Also taking the doubling of carbon dioxide, as a prediction experiment, using the REEP method, the increasing temperature probability along Qinghai-Xizang railway was analyzed comparing with 1990's on the basis of the predicted decadal average temperature, it showed that the maximum (minimum) air temperature will increase 0.4℃ (2.4℃) in future 50 years with the probability 66% (74%); 1.4℃ (6.9℃) in 2001 with 85% (62%).

• Temporal and Spatial Characteristics of Strong Wind and Dust Days in Qinghai-Xizang Plateau and along Qingzang Railway
• BAI Hu-zhi;DONG An-xiang;LI Dong-liang;FANG Feng
• 2005 Vol. 24 (3): 311-315. 
• Abstract ( ) PDF (745KB) ( )
• Based on the meteorological observation data of 66 stations in Qinghai-Xizang Plateau(QXP) from 1971 to 2000, the temporal and spatial characteristics of the days with strong wind, floating dust, blowing-sand and sandstorm in QXP and along Qingzang railway were analyzed. Results show that the days of strong wind in QXP mainly occurs in the main body of Plateau centralizing on near to Toutouhe, There are four cores of dust, they occur often in winter, the spatical distribution pattern change with season is not obvoius. The interdecadal variation of strong wind days is out of phase with that of dust weather, particularly remarkable in the central and western parts of the Plateau. In the former region, the days of strong wind increases with time while days of dust weather slightly reduced. In the latter region, the days of strong wind decreases while variation in the days of dust weather is something like the Chinese character "几" with time.

• Di-Qi Map Method for Predicting Snow Disaster of Qinghai Province
• TANG Mao-cang;ZHANG Yong-jun;TANG Hong-yu;LI Dong-liang
• 2005 Vol. 24 (3): 316-319. 
• Abstract ( ) PDF (847KB) ( )
• A predicting method for snow disaster of Qinghai Province is introduced in this paper. By using the data of snow disaster and the ground temperature at deep level of all weather stations in Qinghai province since 1960, the spatial and temporal characters of the ground temperature at the deep level in Qinghai in August are analyzed. The August earth thermal vortex positions of South Qinghai are also analyzed, and the high correlation between the snow disaster and these earth thermal vortexes distribution is found. So Di-qi map method may be used for predicting the snow disaster of Qinghai Province.

• Annual Mean Surface Air Temperature over Qinghai Plateau in Recent 250 Years Reestablished Using Data of Multi-Piece Tree-Ring
• WANG Qing-chun;QIN Ning-sheng;LI Dong-liang;SHI Xing-he;WANG Zhen-yu;LI Lin;ZHU Xi-de
• 2005 Vol. 24 (3): 320-325. 
• Abstract ( ) PDF (1163KB) ( )
• Through the statistic analyses of temperature and multi-piece tree-ring chronology in different regions over Qinghai Plateau, the method and way of annual mean surface air temperature reestablished by multi-piece tree-ring chronology over Qinghai Plateau are discussed. It is found that the air temperature and tree-ring chronology have a good corresponding relationship, the air temperature is one of main controlling factors of the tree-ring change, especially the chronology can reflect the change of minimum temperature. the difference chronology in the tree-ring chronology is the best one to reflect temperature change. By using the data of six tree-rings chronology, annual mean surface air temperature sequences over Qinghai Plateau in recent 250 years are reestablished.

• Evolution Characteristics of Dry and Wet Climates in Chaidamu Basin in Recent 1100 Years and Its Tendency Prediction
• LI Lin;WANG Zhen-yu;QIN Ning-sheng;LI Dong-liang;ZHU Xi-de;WANG Qing-chun
• 2005 Vol. 24 (3): 326-330. 
• Abstract ( ) PDF (892KB) ( )
• Using the Qilianyuanai tree ring width sequence sampled on the northeastern side of Zongwulun mountain and Shalike mountain of Chaidamu basin and its response remation to the precipitation change, the precipitation sequence in Chaidamu Basin in recent 1100 years is reestablished, and its characteristics of drought and flood evolutionsare analyzed. In view of this, the future evolution tendency is predicted. Theresult shows that the reestablished equation based on the first main component of EOF analyses of Qilianyuanbai tree ring width sequence and the relationship of precipitation sequence in Delinha is stable, which can represent the historical precipitation sequence in Chaidamu; Chaidamu Basin had passed four relative wet and arid stages in the past 1100 years, it was a stage with abundant rainfall from 1971 to 2000, but it had began to decrease since 1990's, at the mean time, the precipitation sequence had the most significant period with quasi three years. The precipitation in Chaidamu Basin will be possibly decreased.

• May~June Surface Temperatures of Chaidamu Basin Reestablished Using Tree-Ring Chronology
• ZHU Xi-de;QIN Ning-sheng;LI Dong-liang;WANG Zhen-yu;LI Lin;WANG Qing-chun
• 2005 Vol. 24 (3): 331-337. 
• Abstract ( ) PDF (289KB) ( )
• Based on the correlation between the tree ring data series in Delingha and Wulan of western Qinghai and surface temperature in Chaidamu Basin in May~June from 1962 to 2001, the sequences of 0 cm surface temperature in Chaidamu Basin in May~June and the thousand year's historical data of maximum surface temperature are reestablished. Applying the methods of average value of product and reduction of error, the reestablished equation is tested. The results show that they are believable. Through the analyzing, it is found that there were 6 main cold and warm periods in the past 1098 years, 12 main abrupt periods at 0 cm surface temperature, and 15 ones in maximum surface temperature series. The period analyese show that both 0 cm and maximum temperature series exist long periods of 183, 122, 91 years and short periods of 6.8, 2~3 years.

• Characteristics of Climatic Evolution in Recent 1000 Years of Permafrost Region along Qinghai-Xizang Railway
• WANG Zhen-yu;LI Lin;LI Dong-liang;QIN Ning-sheng;WANG Qing-chun;ZHU Xi-de
• 2005 Vol. 24 (3): 338-343. 
• Abstract ( ) PDF (1482KB) ( )
• Using the tree ring, the annual average air temperature (1763-1998) and annual precipitation sequence (1518-1983) of permafrost region along Qinghai-Xizang Railway are reestablished, the air temperature on 10 year time scale can be divided into 14 warm periods and 13 cold periods by wavelet analysis, and the Medieval mild phase and little ice age on 30 year time scale are significant. From 30 year time scale, the precipitation in 1591-1640, 1671-1730, 1770-1950 are more than normal, in rest of years vice versa. Now it is still in warm and dry periods. It is found by power spectrum that the main periods of air temperature are 2.0, 2.5, 3.6, 7.2, 2.8 and 117.7 years, while the main periods of precipitation are 2.1, 3.1, 4.5, 7.7, 11.3, 20.8, 28, 62 years, respectively.

• Analyese on Regional Characteristics of Temperature Changes over Qinghai-Xizang Plateau in Recent 50 Years
• ZHOU Ning-fang;Qin Ning-sheng;TU Qi-pu;LI Dong-liang
• 2005 Vol. 24 (3): 344-349. 
• Abstract ( ) PDF (287KB) ( )
• According to the good relationship between the surface air temperature and 500 hPa temperature over Qinghai-Xizang Plateau(QXP), the sequence of continuous and reliable monthly mean surface air temperature over QXP in 1950-2000 were reestablished. Again according to the REOF analyses of the data of the subregions of mean air temperature change for year, spring, summer, autumn and winter were divided into four, two, three, five, and four sub-regions respectirely. The results show that there are obvious regional and seasonal differences over QXP in the recent 50 years. Over all the surface air temperature over QXP in recent 50 years raise, but there are obvious regional and seasonal differences. The changes of mean air temperature in the most of sub-regions are similar to those whole over Plateau, but the temperature warming in spring and winter are more obvious, especially in sub-region I and in spring and winter; howerer the warming in summer and autumn are not so obvious, even there are some cooling occurring, particularly in sub-region I in summer and sub-regions Ⅲ in autumn, their temperature are decreased by -0.26℃ and -0.11℃ respectively.

• Relationship between Dipole Oscillation of Sea Temperature in Indian Ocean and Precipitation and Temperature in Flood Season over Qinghai-Xizang Plateau
• LIU Qing-chun;QIN Ning-sheng;LI Dong-liang;FENG Shu-qing;ZHANG Ji-nong;ZHAO Mei-gang
• 2005 Vol. 24 (3): 350-356. 
• Abstract ( ) PDF (333KB) ( )
• Based on the precipitation and temperature data of 35 stations over Qinghai-Xizang Plateau and anomalous field data of sea temperature over Indian Ocean in last 40 years, by correlation statistics, it is found that the dipole index of abnormal sea temperature over eastern/western Indian Ocean and the precipitation and temperature of flood period over Qinghai-Xizang Plateau has a better relation, especially the dipole index of sea temperature over eastern/western Indian Ocean in January, from December to February and the precipitation of flood period over Qinghai-Xizang Plateau, the dipole index of sea temperature over eastern/western Indian Ocean in last June and the temperature of flood period over Qinghai-Xizang Plateau has a very good correlation. By analyzing 500 hPa height field data in 1961-2002, it is found that the dipole index of sea temperature over eastern/western Indian Ocean has a close relation to the abnormal of Eurasia 500 hPa height field of Northern Hemisphere, which affects on the variation of precipitation and temperature of flood period over Qinghai-Xizang Plateau throush the strong and weak of Indian southwest monsoon.

• Modeling Study on Anomalous Snow Cover Effects over Western and Eastern Parts of Qinghai-Xizang Plateau
• LIU Hua-qiang;SUN Zhao-bo;WANG Ju;MIN Jin-zhong
• 2005 Vol. 24 (3): 357-365. 
• Abstract ( ) PDF (2253KB) ( )
• The anomalous snow cover effects over the western and eastern parts of the Qinghai-Xizang Plateau(QXP) are compared by numerical simulations using the NCAR regional climate model (RegCM2) in which the gravity wave drag induced by subgrid-scale topography has been introduced. The simulations adopt relatively realistic snow mass forcings based on SMMR pentad snow depth data. The main results are summarized as follows: The heavier than normal snow cover over the western part of QXP can last more longer and has positive feedback on that over the eastern part of the Plateau, the former is favorable to the increasing of the latter, but the latter has little effects on the former. So, in contrast with the heavier than normal snow cover over the eastern part of QXP, when heavier than normal snow cover occurs over the western part of QXP, the total anomaly of snow cover over the Plateau is more obvious during the simulations. Both the heavier than normal snow cover over the western and eastern parts of QXP have effects on the atmospheric temperature and potential height fields, and their effects are with basically identical structure characteristics but with different strengths. The heavier than normal snow cover over the western part of QXP has more obvious effects on the regional atmospheric circulation in the later stages.

• Multi-Scale Variations of Snow Cover over QXP and Tropical Pacific SST and Their Influences on Summer Rainfall in China
• PENG Jing-bei;CHEN Lie-ting;ZHANG Qing-yun
• 2005 Vol. 24 (3): 366-377. 
• Abstract ( ) PDF (2315KB) ( )
• The interannual and interdecadal changes of snow cover over the Qinghai-Xizang Plateau(QXP) and sea surface temperature (SST) in the eastern tropical Pacific and their influences on summer rainfall in China are studied by using the wavelet transform and correlation analysis. The interannual change of the snow cover are both the quasi-biennial oscillation (QBO) and fluctuations with time scale about 6~7 years, and those of SST are El Nino Oscillation and QBO. The interdecadal change of snow cover and SST change occurin the late 1970's, snow cover change from little to excessive, SST change from cold to warm. There are significant regional differences among the relationships between the snow cover and SST with different time scales. In some places, their influences strengthen each other,while in another places theyweaken each other. Stronger relationships were found to exist between inter decadal change of snow cover and SST and summer rainfall in China than the interannual variations. Thus, in long-range forecast the effects of the snow cover and SST with different time scales should be taken in account of.

• Mesoscale Numerical Simulation and Diagnostic Analysis of Meiyu Front Heavy Rain in Nanjing in July 2003
• ZHANG Bing;HU Yin-qiao;FU Pei-jian
• 2005 Vol. 24 (3): 378-386. 
• Abstract ( ) PDF (1584KB) ( )
• Mesoscale model MM5 is used in this paper to investigate the course of Meiyu front rainstorm in Nanjing on 4~5 July 2003("03.7"), and it is shown thatits simulation ability is good about this process. The results show that the time of frontogenesis is earlier 12 h than that of heavy rain occurred. The results also suggest that the development of jet stream is about earlier 2 h than that of heavy rain. Increasing of the lower level jet stream and enhancing of absolute value of negative divergence that produce convergence on the low-level of troposphere to cause violently the occurrence of heavy rain. But it is the heavy rain that causes the increase of the relative vorticity. The moist potential vorticity analysis during the heavy rain indicates that the lower level of troposphere is negative averagely in large area. This means the heavy rain have a feature of moist symmetric instability. But the result from the center of the heavy rain (rainfall>20 mm·h^-1) is accompanied by a small positive moist potential vorticity on 850 hPa. This shows that the center in heavy rain is almost moist symmetric stability after the release of convective energy.

• Climatic Effects of 100 hPa Easterly Air Flow in Tropical (I): Its Relationship with Climate Anomalies in South China
• XU Zhong-feng;QIAN Yong-fu
• 2005 Vol. 24 (3): 387-395. 
• Abstract ( ) PDF (1782KB) ( )
• The relation between the tropical easterly intensity at 100 hPa and climate anomaly in South China is analyzed by using the data of NCEP/NCAR reanalysis and the index of the west Pacific subtropical high. The results are as follows:(1) There is a remarkable negative correlation between the winter easterly intensity and both the same time and the March rainfall in South China. The composite analysis shows that there is a southwesterly anomaly over the Indochina Peninsular and South China in week easterly year, which is favourable to transfer the warm and moist water vapor from the Bay of Bengal to the South China. (2) The summer air temperature averaged over South China has a close relationship with the previous easterly intensity average from the October in the last year to the February in the same year, and their correlation coefficients are -0.617. The composite analysis shows that the west Pacific subtropical high is stronger than ever, and its western limit is far westward in the weak easterly year. As a result, the clear days are more than ever in the South China and the air temperature is higher.

• Temporal and Spatial Characterstics of South American Lightning Activities and Their Relationship with SST in East Pacific
• XIONG Ya-jun;QIE Xiu-shu;GUO Fen-xia;YUAN Tie;ZHOU Yun-jun
• 2005 Vol. 24 (3): 396-403. 
• Abstract ( ) PDF (1339KB) ( )
• The EOF and SVD techniques have been used to analyze the spatial anomaly features and time evolution rules of lightning activities in South American and their relationships with East Pacific SST using the eight years (from June 1995 to February 2003) data of LIS/OTD flash and NOAA Extended Reconstructed SST. The results show that the first two loading vector fields reflect well the whole anomaly pattern structure of lightning activities in South American. The first loading vector field shows a same variation tendency of lightning activity in the whole study area, while the second show the different variation tendencies in the south and north parts. The first loading vector shows that the whole lightning activities do not increase (or decrease) obviously in the South America during El Nio, while the spatial structure revealed by the second loading vectors show a good correlation with the SST in Nio3 area. The SVD analysis technique further suggests that there are a good relationship between SST in the regions of 20°~30°S, 110°~130°W and 10°~5°N, 160°W~180° and the lightning activities in Peru and east Brazil, but the variation of SST results in different variation tendencies in Peru and east Brazil.

• Zonal Symmetry Structure of Arctic Oscillation
• YANG Xiao-yi;GUO Pin-wen;HU Yue-wen
• 2005 Vol. 24 (3): 404-409. 
• Abstract ( ) PDF (259KB) ( )
• Using the monthly dataset of NCEP/NCAR reanalysis, the zonal structure of the Arctic Oscillation(AO) and its correlation with the zonal-mean zonal wind and the meridional circulation are studied. The results indicate that the zonal symmetry and annular mode predominate AO in wintertime and summertime, but more prominent in the AO active period in wintertime. With the shift of current zone and the attenuation of the polar vortex, the node of the summertime AO zonal symmetric mode transfers poleward compared with that of the wintertime AO. In corresponding with AO zonal symmetric mode, zonal-mean zonal wind exhibits dipolar pattern in winter which extends upward into stratosphere. In summertime this dipolar pattern weakens to great extent and limits in the bound of troposphere. Enhanced Ferrel cell and Hadley cell manifest themselves in mean meridional circulation anomaly in consistent with AO symmetric mode both in wintertime and summertime, which is in favor of the positive feedback of AO and thus the maintenance of AO mode.

• Scaling Laws of Temperature Anomaly over Global, Northern Hemisphere, and China in Recent 140 Years
• JIANG Tian-han;DENG Lian-tang
• 2005 Vol. 24 (3): 410-414. 
• Abstract ( ) PDF (226KB) ( )
• To study the long range power-law correlations of the monthly average anomalies over the global, Northern Hemisphere, and China in the recent 140 years,the detrended fluctuation analysis (DFA)method is applied in this paper, which can effectively eliminate noise and possible nonstationarities in the data. The preliminary results show that there exist two different scaling invariant ranges, divided by one crossover in the three temperature series, which may indicate two different underlying physical mechanisms. Fist of all, they all present the positive long range correlations, and the persistence of the global temperature is the strongest, while China weaker than Northern Hemisphere. Secondly, the global and Northern Hemisphere temperatures can nearly behavior like 1/f noise, and China temperature can show behaviors between 1/f noise and Brown noise.

• Abnormal Features of Sensible and Latent Heat Fluxes in Arid Region of Northern China
• HUI Xiao-ying;WANG Cheng-hai;ZUO Hong-chao;DONG Wen-jie
• 2005 Vol. 24 (3): 415-421. 
• Abstract ( ) PDF (1088KB) ( )
• The sensible and latent heat fluxes were analyzed by using NCEP/NCAR reanalysis data. The results indicated that the inter annual changes of the sensible and latent heat fluxes have 2~3 sensitive regions in arid region of Northern China. They located in Northwest, North China and Inner Mongolia, respectively, the North China, and Inner Mongolia region in East China was the most significant region. The mean inter annual change of representative regions such as Northwest North China and Inner Mongolia showed that the sensible and latent heat fluxes appear an abrupt change in the late 1960's, and the sensible heat flux keep a higher value in the above-mentioned two regions and the change of the latent heat flux appear opposite change in 1970's.

• Function Relationship between Daily Rainfall in China and Its Area in Horizontal Region
• CHENG Bing-yan;GU Wan-long;LI Yun;DING Yu-guo
• 2005 Vol. 24 (3): 422-427. 
• Abstract ( ) PDF (298KB) ( )
• A function relationship between the daily rainfall over a large area and its area has been researched using the observed precipitation data in China in recent 40 years. The result shows that the statistical distribution of the daily rainfall field over large coverage(like China) appear usually obvious leftward skew pattern. Comparing the negative exponential distribution with the Probability Density Function of Weibull distribution shows that the latters fitting result is better than the former one. The negative exponential distribution pattern might is only suitable for the precipitation process under the same synoptic system or smaller region, and in a larger region(say China), it is possible more suitable for Weibull distribution fitting because of the combination effects of the varieties of synoptic systems.

• Analyese on Variation Characteristics of Atmospheric Pollutant in a Group of Cities in Central Liaoning from 1987 to 2002
• MA Yan-jun;CUI Jing-song;LIU Xiao-mei;ZHANG Jing
• 2005 Vol. 24 (3): 428-435. 
• Abstract ( ) PDF (1706KB) ( )
• Based on the monitoring data of atmospheric pollution(TSP, PM10, SO₂, NO_X) in a group of cities of central Liaoning(Shenyang, Anshan, Benxi, Fushun and Liaoyang) during the period of 1987-2002, the conditions of atmospheric pollution in a group of cities of central Liaoning are analyzed. The results show that the main atmospheric pollutants there are TSP and SO₂. The atmospheric pollution in winter is the most serious in a year; and in summer, the most light. The change trend of TSP,PM₁₀ and SO₂ in 5 cities in 1987-2002 has been decreasing year-to-year, the interannual changes of NO_X are not obvious. The atmospheric polltion in Benxi is the most serious in the group of cities, then it is Anshan, Shenyang, Fushun and Liaoyang in the order.

• Simulation of Effect of Climate Factors on Dust Storm Frequencies in Mid-and North-Parts of Ningxia
• LI Yan-chun;ZHAO Guang-ping;LI Yan-fang;ZHENG Guang-fen;DING Zhong-lu
• 2005 Vol. 24 (3): 436-441. 
• Abstract ( ) PDF (340KB) ( )
• Using the milt-year meteorological data at six representative stations in the mid-and north-parts of Ningxia, the effects of the monthly mean wind velocity, soil moisture and coefficient of wind erosion and desertification in underlying surface on sand storm frequencies are analyzed. The effect indexes of the climatic factors on sand storm frequencies are calculated. Also the regression equation suitable for fitting sand storm frequencies in the mid-and north-parts of Ningxia have been finished.

• Test of Ecological Effect of Artificial Precipitation Stimulation of Maqu Region in Upper Reach of Yellow River from 1997 to 1999
• DELI Geer;WANG Qing-chun;ZHOU Lu-sheng;SUN An-ping;XU Wei-xin;QI Ru-ying;LIU Bei
• 2005 Vol. 24 (3): 442-449. 
• Abstract ( ) PDF (339KB) ( )
• Taking the normalized vegetation index and grass productivity as biological index, the idea and method of the ecological effect verification of artificial precipitation stimulation are discussed. Taking the artificial precipitation stimulation in Maqu region of upper reach of Yellow River from 1997 to 1999 for an example, we do actual calculation. The result shows that there is a positive effect to rise grass productivity and increase vegetation cover due to the artificial precipitation stimulation in Maqu region, the average grass productivity is double or more and vegetation cover significantly increase. From the primary estimation, the ratio of cost to output of pastare economic benefit is 1:9.7 in the region of artificial precipitation stimulation of Maqu in 1998.

• Application and Research on Q-Vector Analytic Method in China
• YUE Cai-jun;SHOU Yi-xuan;YAO Xiu-ping;SHOU Shao-wen;QI Liang-bo;SHI Hong
• 2005 Vol. 24 (3): 450-455. 
• Abstract ( ) PDF (282KB) ( )
• The domestic application and research on the Q-vector have systematically been reviewed since 1980's, the formulas of quasi-geostrophic, semi-geostrophic, ageostrophic and ageostrophic wet Q-vector, and along with their corresponding ω-equations taking the divergence of each kind of Q-vectorsas forcing term are presented and given, and the characteristic of each Q-vector analytic method is simply introduced as well. What's more, the expressions of the revised wet Q-vector and the generalized C-vector are provided. Certainly, in this field some further studies are still needed.

• Severe Convective Weather Warnings and Its Improvement with the Introduction of the NEXRAD
• YU Xiao-ding;WANG Ying-chun;CHEN Ming-xuan;TAN Xiao-guang
• 2005 Vol. 24 (3): 456-464. 
• Abstract ( ) PDF (1076KB) ( )
• A brief review is given on the convective storm classification, the identification of the convective storm strength and severe storm warnings methods by radar, and the severe convective storm warnings improvements with the installation of the NEXRAD.