Current Issue

• Numerical Simulation of Microclimate Effect in Jinta Oasis
• Lü Shi-hua;SHANG Lun-yu;LIANG Lin;LUO Si-qiong
• 2005 Vol. 24 (5): 649-655. 
• Abstract ( ) PDF (1285KB) ( )
• Using the NCAR nonhydrostatic mesoscale model MM5V3.6,triple nested technique and the NCEP reanalysed data in July,2003,the microclimate effect in Jinta oasis was simulated.The main results show that the Oasis can change the circulation structure and humidity distribution of original desert area.The boundary layer height is lower in oasis and higher in desert and the structure of lower boundary layer is actual a protected layer,which make the atmospheric moisture of oasis to keep in the lower boundary layer and protected the oasis ecological system.Oasis has low sensible heat flux and high latent heat flux;but vice versa in desert.The inhomogeneous distribution of energy and moisture drives the oasis circulation,in which there is the downdraft over the oasis and the updraft over the desert.

• Interdecadal Characteristics of the Influence of Northward Shift and Intensity of Summer Monsoon on Precipitation over Northern China in Summer
• WU Chang-gang;LIU Hong-sheng;XIE An
• 2005 Vol. 24 (5): 656-665. 
• Abstract ( ) PDF (929KB) ( )
• The location of northward shift of East Asian Summer Monsoon is calculated by using NCEP/NCAR air temperature and specific humidity reanalysis data in recent 50 years.It is found that there is obvious interdecadal change in the north boundary of monsoon region,and the years with the far north boundary centralize in 1950's and 1960's,with the far south,in 1980's and 1990's,the interdecadal change of north boundary of summer monsoon in each monsoon region is consistent.The regional monsoon index is defined by using these data,in order to reflect the relationship between the intensity of East Asian summer monsoon and drought/flood in Northern China and improve the low correlation between the situation of northward shift of summer monsoon and drought/flood in Northern China,and the arid and semiarid regions where is sensitive to the intensity of summer monsoon is compared by composite analysis.In the last,the relationships between the regional summer monsoon index and the precipitation on different time scales in July and August is discussed by wavelet analysis.The correlation between regional summer monsoon index and precipitation in summer is high on interdecadal scale about 15 years and on interannual scale of 3~5 years.

• Chaotic Study on Drought of Shaanbei Loess Plateau
• LUO Hui;TAO Jian-hong;ZHONG Wei-zhou;WANG Mei-hua;PANG Wen-bao
• 2005 Vol. 24 (5): 666-671. 
• Abstract ( ) PDF (337KB) ( )
• We introduce the complexityof chaos and calculation method about the Correlation Dimension.Taking time series drought duration in the Shaanbei Loess Plateau as example,we set forth how to distinguish chaos by using the Correlation Dimension and how to get it from time series of single variable.It is a simple and feasible method in judging chaos identity of drought.

• Numerical Simulation of Mesoscale Convective System of Southern Branch Trough Heavy Rainfall in Yunnan Region
• YAN Hong-ming;XIAO Zi-niu;ZHANG Xiao-ling;LI Jian-tong
• 2005 Vol. 24 (5): 672-684. 
• Abstract ( ) PDF (2280KB) ( )
• A heavy rainfall case(11~13 May,2002) in Yunnan low-latitude plateau caused by Southern Trough was selected in the paper.The precipitation and circulation can be simulated successfully by MM5.Based on the high-resolution products of MM5 model,the structure characteristics of mesoscale convective system was studied.The results show that there is current convergence of southwest and southeast in the low levelbut predominant southwest wind in the upper level during the heavy rainfall period.On the southwest side of convergence line,an area with strong positive vorticity and strong convergence convection of warm and moisture air can be detected.Under the affection of cold air nearby the convergence line,the warm and moisture air ahead of trough converge and rise upward to result in heavy rainfall.The rainfall located on the southwest side of the area with strong positive vorticity,convergence and warm and moisture upward current on 700 hPa level.The evolution of the mesoscale convective system space structure is revealed in further analysis.During the early period of convective developing,the positive and negative vorticities are dispersed separately in vertical and horizontal directions and indicate multiple modes.The convergence and divergence,upward and downward motions present the same feature.But in the period of convective developing,it comes to single mode pattern,which is with positive vorticity,convergence and upward current in low level,but negative vorticity,divergence and downward current in upper level nearby the convergence line.The convergence is shallow in low level located between the land surface and 600 hPa.But the positive vorticity and upward current are much more deeper,which can reach 400 hPa to 200 hPa levels.The slant vertical structure is noted in the low-latitude plateau mesoscale convective system, which slops from surface convergence area to northeast upper level(to higher latitudes).This incline characteristic of vertical structure is different from that of the mesoscale convective system over South China.

• Prediction of 0 cm Average Ground Surface Temperature Changes along Qinghai-Xizang Railway
• LI Dong-liang;GUO Hui;LI Yue-qing;ZHONG Hai-lin
• 2005 Vol. 24 (5): 685-693. 
• Abstract ( ) PDF (1698KB) ( )
• The annual average 0 cm ground surface temperature of the stations along the Qinghai-Xizang railway correlated well to each other,especially the correlation of 10-year running mean average sequences of them,which is as high as 0.92.According to the results,the 0 cm average ground surface temperature series along the Qinghai-Xizang railway from 1961 to 2003 are constructed.The results show that: The 0 cm ground temperature increased about 1.1~1.5℃ during the past 40 years.The warming ratio of it is 0.44℃/10a.The effects of increased the atmospheric carbon dioxide concentrations(CO₂) will be favorable torise up the 0 cm ground temperature along the Qinghai-Xizang railway,but vice versa for sunspot cycle length(SCL) before year 2030.The response between 0 cm ground temperature and both the atmospheric CO₂ concentrations and SCL have lagging about 10 years respectively.Based on the predictions of the future atmospheric concentrations of CO₂ and SCL,the 0 cm ground temperature along the Qinghai-Xizang railway could be the warmest about in 2010,and then,it maybe lower thanthe average values of 1970's to 1990's,would decrease evidently till about 2030.The next round calefaction of the 0 cm ground temperature along the Qinghai-Xizang railway could begin in 2040. Considering the combined effects of both CO₂ concentrations and SCL,the average minimum,the maximum and annual 0 cm ground temperatures along the Qinghai-Xizang railway would increase 0.2℃,1.0℃ and 0.6℃ during the next 50 years.

• Interdecadal Change Trend of Surface Air and Ground Temperatures along Qinghai-Xizang Railway and Relationship between the Change and Terrain
• LI Dong-liang;LIU Miao;ZHONG Hai-ling;WU Qing-bai
• 2005 Vol. 24 (5): 694-699. 
• Abstract ( ) PDF (1278KB) ( )
• The monthly mean surface air temperature,0 cm ground temperature of weather stations along Qinghai-Xizang railway from beginning to 2002 are analyzed.Seasonal and annual mean temperature data are found from 1961 to 2002 by using interpolation.The analyzed result showed that the variation of temperature is obviously along Qinghai-Xizang railway in recent 40 years.The temperature ascending rate is the most obvious in winter and autumn.The temperature ascending rates are 0.41℃/10a and 0.40℃/10a respectively.The temperature ascending rate in spring is only 0.23℃/10a.The ascending rates of annual mean air temperature and 0 cm ground temperature are 0.33℃/10a and 0.37℃/10a respectively,and 0 cm ground temperature ascending rate is faster than air temperature ascending rate.The temperature ascending rate have anticorrelation with sea level elevation,and its coherency coefficient is 0.807.The temperature ascending rate decrease with sea level elevation increasing.The temperature ascending rate in basin is higher than temperature ascending rate in mountain.There is 0.767 coefficient of coherency between the variations of 0 cm ground temperature and air temperature.In comparatively colder times,the fluctuation extent of air temperature is bigger than the fluctuation extent of 0 cm ground temperature.In comparatively warmer times,the ascending of 0 cm ground temperature is faster then air temperature.

• The Simulated Result Analyses on Climate Changes over Qinghai-Xizang Plateau and along the Railway in the Coming 50 Years
• XU Ying;ZHAO Zong-ci;LI Dong-liang
• 2005 Vol. 24 (5): 700-707. 
• Abstract ( ) PDF (430KB) ( )
• The predictions of surface air temperature and precipitation changes over Qinghai-Xizang Plateau and along the railway due to the green house gas effect of human activities in 21^st century was studied based on the simulation results of five atmosphere-ocean coupled AOGCMs models(CCCma,CCSR,CSIRO,GFDL,Hadley).The trends of temperature and precipitation changes in former 50 years of 21^st century are analyzed,including the distributions of surface air temperature and precipitation changes over Qinghai-Xizang Plateau in 2011-2040 and 2041-2070. Results of the projections showed that the warming is to continue over Qinghai and Xizang by both the scenario SRES-A2 and B2.The warming range is 1.6℃ along Qinghai-Xizang railway in the early century and 2.4~3.4℃ in the middle century.The analyses of every 10 year mean tempeartures show that,for scenario A2,the temperature change along Qinghai-Xizang railway around 2050 years is 2~3 times as against around2010years.For A2,the temperature is between 2.56~2.96℃,for B2,between 2.37~2.65℃.The temperature increasing in the winter is more than in the summer.The precipitation will increase in 21^st century.

• Response of Permafrost over Qinghai Plateau to Climate Warming
• WANG Qing-chun;LI Lin;LI Dong-liang;QING Ning-sheng;WANG Zhen-yu;ZHU Xi-de;SHI Xin-he
• 2005 Vol. 24 (5): 708-713. 
• Abstract ( ) PDF (1363KB) ( )
• Using the annual averaged ground surface temperature data of meteorological observation over Qinghai Plateau,the relationship models of annual mean ground temperature and altitude as well as latitude/longitude are established,combining with geographic information analysis system and DEM data,the permafrost distribution map over Qinghai Plateau is also simulated,the response of permafrost to climate warming and its impacting on ecology environment over Qinghai Plateau are finally analyzed.The results show that the permafrost area of Plateau is decreasing while its bottom is ascending with the global warming, especially,this kind of degeneration is getting more significant over the disconnected margin of permafrost and island-like region of permafrost.Comparing with 1960's,the distribution height of permafrost bottom in 1990's over Plateau has been ascending approximately 71 m,while the seasonal depth of permafrost has decreased to 19 cm.The spatial distribution characteristic of annual variation of maximum permafrost depth corresponds with the spatial characteristic of air temperature variation over Qinghai Plateau in 40 years.

• Simulation of Climate over Qinghai-Xizang Plateau Utilizing RegCM3
• ZHANG Dong-feng;GAO Xue-jie;BAI Hu-zhi;LI Dong-liang
• 2005 Vol. 24 (5): 714-720. 
• Abstract ( ) PDF (322KB) ( )
• The simulation of climate in East Asia region in 15 years were carried out by the RegCM3 nested into ERA40 re-analysis data.The simulation of the temperature and precipitation distribution and changes over Qinghai-Xizang Plateau and along the Qinghai-Xizang Railway were mainly investigated.The results show that RegCM3 model has ability to simulate the basic character of the spatial distribution of precipitation and temperature over Qinghai-Xizang Plateau and along the railway region.At same time,the model simulation can provid more reliable information of local precipitation and air temperature for the region of rare observation station.The model can reproduce well the precipitation along Qinghai-Xizang railway,especially the change trend of air temperature in each month of a year.The annual change of air temperature in the region is well simulated,but the simulated ability to the annual change of precipitation in this region remain to be improved.

• Retrieving of Land Surface Temperature over Jinta Area Using LANDSAT-5 TM Data
• MENG Xian-hong;Lu Shi-hua;ZHANG Yu;ZHANG Tang-tang
• 2005 Vol. 24 (5): 721-726. 
• Abstract ( ) PDF (1412KB) ( )
• The thermal infrared band of Landsat-5 TM was used to retrieve Land Surface Temperature(LST) in three different algorithms,and the results comparing with the observations indicate that all the algorithms can retrieve the distribution of LST,the first and two algonthms are the best ones because of the Absolute errors of them are both less than 1.9℃,but the third algorithm is not as good as them.

• A Technique of Fast Median Filtering and Its Application to Data Quality Control of Doppler Radar
• CUI Zhe-hu;CHENG Ming-hu;WU Qiu-li;WANG Bai-zhong
• 2005 Vol. 24 (5): 727-733. 
• Abstract ( ) PDF (1268KB) ( )
• A technique of fast median filtering is developed which fit to control data quality of Doppler radar.Its merit is that correlative information between signals data in neighboring median filtering windows are considered.In filtering processing,since sequential information of data in prior filtering window preserved as reference of current filtering window,it reduce the number of calculating for current filtering window.So calculating efficiency is increased.Final the technique is used in quality control of Doppler radar.3,5 and 7points of median filtering are tested.It is found that the median filtering of 5 points is better in quality control of Doppler radar data.Signal of Doppler radar is preserved better and noises of random pulse are eliminated effectively.

• The Effect Evaluation for Precipitation Enhancement Experiment in Tianshan Mountains of Xinjiang
• GAO Zi-yi;ZHANG Jian-xin;LIAO Fei-jia;LIN Ke
• 2005 Vol. 24 (5): 734-740. 
• Abstract ( ) PDF (319KB) ( )
• Based on the historical hydrology data,a study on the section and the arrangement of statistical variable have been conducted,and a new evaluation method was proposed.As statistical variable,the average ten-day period flow which have been arranged in the light continuous way was adopted.Pre-evaluation result of the regional regression experiment shown that a seeding effect only accounted for amount to 4.3% of average flow in historical period can be tested,with a significant level of 0.05 during a 9-year experiment period.The efficacy of statistical test is improved significantly.The statistical evaluation was accomplished for artificial rainfall experiment in Ürümqi River basin of Tianshan mountains of Xinjiang during summer from 1994 to 2002.The continuous arranged average ten-day period flow and month precipitation were selected as statistical variable.The results indicated a 3.5% increase in average flow with significance level of 0.035 and a 19.9% increase in average precipitation with significance level of 0.005.

• Analyses on Atmospheric Stratification Characteristics of Thunderstorms over Qinghai-Xizang Plateau
• ZHANG Cui-hua;YAN Mu-hong;DONG Wan-sheng;ZHANG Yi-jun
• 2005 Vol. 24 (5): 741-747. 
• Abstract ( ) PDF (290KB) ( )
• The thunderstorm activity is very frequent in summer in Naqu district of Qinghai-Xizang Plateau.It occurs in the consequence of thermal and dynamic effects topographically.The storms are usually not very severe,with the maximum radar reflectivity not exceeding 40 dBz in general.The relative cloud top can extend to 10.0~13.0 km,with little differences between severe and weak thunderstorms.The thunderstorm occurs usually at 13:00~19:00 Beijing time,the peak value appears at 16:00 or so,and the duration is about 30 minutes.Weak convection occurs sometimes in nighttime with maximum reflectivity of about 20 dBz.The atmospheric stratification of the Plateau storm is totally different from that of plain storm.The thunderstorm on plateau is usually instable on whole layers,up to the height of 100 hPa,and with low instable energy.The CAPE value of severe thunderstorm is about 782 J·kg^-1 on average and that of weak 406 J·kg^-1 approximately.The CAPE is homogeneously distributed without instable stratification of large energy.The inverse humidity occurs near ground with thickness about 1~2 km and the value of 60%~80% on average(after the rainy season).The atmospheric stratification forementioned is similar for both the heavy and weak thunderstorms;it can stimulate convection with large developing height but little intensity and energy.This special stratification revealed the particular structure of thunderstorms on plateau.The developing intensity of thunderstorm is characterized by its lightning frequency.Usually a statistical dependence can be established between the lightning frequency and the singular parameter of thunderstorms such as the height of cloud top;whether the thunderstorm is heavy or weak can be predicted by measuring the lightning frequency.However it is unsuitable for thunderstorms on plateau;a synthetic relation has to be established between the lightning frequency and the multi-parameters of thunderstorm.

• Simulation on Air Pollution of Lanzhou Utilizing Models-3 Air Quality Model System
• AN Xing-Qin;ZUO Hong-chao;Lü Shi-hua;ZHU Tong
• 2005 Vol. 24 (5): 748-756. 
• Abstract ( ) PDF (2798KB) ( )
• The characteristic of Third-Generation Air Quality Modeling System and its application to Lanzhou have been introduced in somewhat detail.Because air pollution is serious during winter heating period,a case in December 2002 is chosen and a 48 h integrating simulation experiment was carried out utilizing the latest pollution sources data.Comparing the simulation results of SO₂,NO₂ and O₃ with the observation ones,it is shown that the model system can better simulate the spatial distribution trend of SO₂ and NO₂.Also the simulation and monitoring results are more identical and the simulation concentration field is more even.The simulation result of ozone is unanimous basically with data analysis and according with the formulation mechanism of the ozone too.So this air quality model system has ability to simulate air pollution transport in complicated topographical city of Lanzhou.

• Research on Dust Storm Monitoring Model Based on EOS/MODIS Data
• HAN Tao;LI Yao-hui;GUO Ni
• 2005 Vol. 24 (5): 757-764. 
• Abstract ( ) PDF (1585KB) ( )
• Through analyzing the spectral characteristic of the MODIS visible bands,the methods of monitoring dust storm is putted forward by using MODIS visible bands data.Based on abundant informations of the MODIS visible bands,the distinguishing functions of different spectral features of varions surface information were construct as branches of decision tree.The some dust storm weather processes were timely monitored by using the decision tree.The monitoring results show that the methods are of valuable for practical use.

• Observation Study on Mass Concentration of Dust Aerosols in Dunhuang
• LIU Li-chao;SHEN Zhi-bao;WANG Tao;Zhou Mao-xian;Sadayo Yabuki;Shinji Kanayama
• 2005 Vol. 24 (5): 765-771. 
• Abstract ( ) PDF (1329KB) ( )
• The physical and chemical characteristics of dust aerosols originated from desert area of northern China attracted more and more attentions in recent year,whereas most of studies are based on the short-term observation or typical dust events.In the last 30 months,a long-term study on dust aerosol was conducted using high-volume sampler and Anderson sampler in Dunhuang,which is located in the west part of Hexi corridor and well known as one of the most important dust source in China.The basic mass concentration characteristics of dust aerosol are obtained.The annual change features of total mass concentration of dust aerosol shows the close correlation with those of meteorological data.On the average,the amounts of TSP mass concentration shows different quantitative levels and distinct distributions of mass concentration-particle size during different weather conditions.The comparative analysis with experimental results from Shapotou regions shows that mass concentration of the dust aerosol is lower in clear atmosphere and much higher during dust events.

• Characteristics of Photosynthestically Active Radiation at Clover Land over Ejina Region
• YAO Ji-min;GAO Xiao-qing;FENG QI;GU Liang-lei;ZHU De-qin
• 2005 Vol. 24 (5): 772-776. 
• Abstract ( ) PDF (1256KB) ( )
• Using the observational radiation data in the Chaganmaodao Fodder Basis(mainly planted the clover) in Ejina from June to September 2001,we analyzed the monthly variations,diurnal variations,extreme values of the PAR and the proportions(η_Q) of PAR in short wave irradiance.Moreover,we compared the results with the corresponding variables in Zhangye,Linze,Taihu regions and at Texas station,US,and it is found that the gross of PAR in summer,monthly average daily gross and each extreme value are higher.The irradiative resource is abundant.There are distinctly differences between the PAR's variations on the clear and cloudy days.The cloud and water vapor,intensity of solar radiation,photoperiod have important influences on η_Q.

• The Simulation of Precipitation in China in Summer of 2003
• ZOU Xu-dong;XIE Zheng-hui;SHI Xue-li;WANG Cheng-hai
• 2005 Vol. 24 (5): 777-783. 
• Abstract ( ) PDF (1909KB) ( )
• The temporal and spatial variations of the precipitation and soil water content over China during June to August 2003 have been simulated and studied by using the RegCM-NCC model and the NCEP large-scale reanalysis data.The results show that the RegCM-NCC can successfully simulate the flood in Changjiang-Huai river region,but it can't represent the severe drought to the south of Changjiang River and South China in mid-summer well.The simulated soil water content can well reflect the precipitation and flood in the different regions including the flood in Changjiang-Huai river region and the severe drought to the south of Changjiang River and South China.The preceding high soil water content in Changjiang-Huai river region and following severe precipitation are main reason of forming flood in this region.

• Analyses of A Yunnan Rainstorm Process Influenced by the "Imbudo" Typhoon
• GUO Rong-fen;LU Ya-bin;LI Yan;HAI Yun-sha;GAO Min-qi
• 2005 Vol. 24 (5): 784-791. 
• Abstract ( ) PDF (1068KB) ( )
• Using the routine data of Micaps,FY-2 satellite infrared enhanced image and CINRAD-CC rada data,the rainstorm process in Yunnan province at 20:00 on 25~26 July 2003 caused by the Imbudo typhoon moving westward was analyzed.The result showed that because the westward extension and strengthning of subtropical high,the strong southerly low level jet on the west edge makes the moving westward tropical cyclones in Yunnan to maintain and strengthen and that the MβCS devolopes into MαCS-MCC within the typhoon low depression system in the boundaries of Yunnan province under the favorable large-scale background.It is found that the unstable energy accumulation and water vapour convergence in the lower layer of troposphere are a trigger mechanism of this rainstorm by index K,θ_se,ageostrophic wet Q-vector and ageostrophic wet Q-vector divergence.The orographic lifting leads to the developing of typhoon low pressure,which is one of the import reasons of this heavy rainstorm.Dopplar rada echo showed that there was obvious cyclonic spiral band echo on large-scale and it combines with the several short strong echo bands.In Doppler rada speed picture,the anti-wind zone,cyclonic convergence zone,gale zone and durative warm advection are the direct synoptic systems of causing this rainstorm.

• Analysis on Symmetric Instability of "2003.1" Snowstorm Event in Southeast Guizhou
• CHI Zai-xiang;HU Yue-wen;Bai Hui
• 2005 Vol. 24 (5): 792-797. 
• Abstract ( ) PDF (571KB) ( )
• The symmetric instability criterion is applied to analyze a rare snowstorm weather event in Southewst Guizhou on January 5~6,2003.The result indicates that the snowstorm formed in the symmetric instability atmosphere,the low-level jet triggers the convergence ascending of tropospheric warm and humid airflow and the release of symmetric instability power,thus it appear the snowstorm weather.In the event,southwest vortex,the shear line in east-west direction and the region of snow storm moved towards the area of symmetry instability.

• Singular Spectrum Analysis of Surface Air Temperature and Precipitation Series in Chongqing
• LI Yong-hua;LIU De;ZHU Ye-yu;GAO Yang-hua;MAO Wen-shu
• 2005 Vol. 24 (5): 798-804. 
• Abstract ( ) PDF (303KB) ( )
• Using the singular spectrum analysis,the climatic feature of moth-to-moth surface air temperature and precipitation in Chongqing have been analyzed during the past years.The results show that the quasi-periods of air temperature series are main about 2 and 4 years and 16 months.And the quasi-periods of precipitation series are main about 4 and 2 years and 8~16 months.The variation tendency of air temperature is descendant.It is opposite to the tendency of the variations of temperature of global,Northern Hemisphere and China.The change of precipitation is more complex than that of temperature,and the period is not more obvious than the former.

• Analyses on Circulation and Dynamic Features of A MCC on the Side of Northeast Qinghai-Xizang Plateau
• HOU Jian-zhong;SUN Wei;DU Ji-wen
• 2005 Vol. 24 (5): 805-810. 
• Abstract ( ) PDF (653KB) ( )
• The environment and quantity field of MCC which occurred in northeast on Qinghai-Xizang Plateau on July 28,1991 are diagnostic analyzed,and its forming mechanism is studied.The reference index of this kind of weather forecast is given.

• Analyses on Spring Rainfall Spatial and Temporal Changes of Shandong Province Using EOF
• GAO Liu-xi;LIU Qin-yu
• 2005 Vol. 24 (5): 811-815. 
• Abstract ( ) PDF (657KB) ( )
• Based on the precipitation data at 81 surface stations of Shandong Province during spring of 1961-1998,EOF method is used to analyze spring precipitation of the Province in this article.According to total accumulation variance contributing rate and space distribution characteristics,the first three typical fields(whose contributing rate is 81.30%) can indicate the main characteristics of Shandong spring rainfall distribution.There exists three patterns for the precipitation: The same anomaly in whole Province,different anomalies between both in southeast and northwest and in southwest and northeast directions.There are four areas about Shandong spring rainfall: Areas Ⅰ(Rizhao,Linyi,Zaozhuang and Jining) is the south area,Area Ⅱ(Yantai,Weihai,Qingdao and the east in Weifang) is the east area,Area Ⅲ(Heze and Liaocheng) is the west area,Area Ⅳ(the other ones) is the north area.The same anomaly in whole Province is a base pattern in every month during Shandong spring.Drought disaster easily occurs during Shandong spring.There is a 4.8~6 year oscillation periods during Shandong spring precipitation.

• Changes of Surface Average Air Temperature in Lanzhou under Background of Global Warming
• LIN Shu;WU Hong
• 2005 Vol. 24 (5): 816-822. 
• Abstract ( ) PDF (1300KB) ( )
• Using the month-to-month surface average air temperature of Lanzhou from 1932 to 2002,the basic weather characteristic,interdecadal change,abnomal cold and warm change trends of temperature in Lanzhou in 71 years are analyzed.The analyzed results show that there are two warm periods and a cold period about the air temperature of four seasons in 71 years.The warming of first warm period is mainly in spring,summer and autumn,and winter is in the cold period.The second warm periods first start from winter,there is continuous significant warming after an interval of 1~2 years among four seasons.The warming argument in the second warm periods is obvious higher than that of the first warm period,and its duration is longer than that of one too.The significant feature of four seasons is to warm at the same time,the warming argument in winter is the biggest.The 1960's is the coldest 10 years,the temperature drop in summer is the most obvious.The 1990's is the warmest 10 years.the winter warming is the most obvious. The abnomal frequency occurred in 1990's is the most,next in the 1960's and 1970's,and the least in the 1980's.The average air temperature has rised with linear trend of 1.4℃/100a in Lanzhou since 71 years,the rate of temperature increasing in winter and autumn is the highest in the last 10 years.

• Change of Some Climate Characteristic in Shenyang Under Global Warming Condition
• ZHOU Xiao-shan;CHEN Li-qiang;LI Ji;Yang Sen
• 2005 Vol. 24 (5): 823-828. 
• Abstract ( ) PDF (1204KB) ( )
• Shenyang locates the sensitive zone of global climate change.In recent 100 years,the temperature has raised 1.7℃,and it has brought many local climate phenomenon change which relates to the agronomic activities.The cultivate period increased 6 days in recent 50 years,cold harm in the period of main crop nutrition reduced,but the change of low temperature in summer wasn't obvious,the first frost date obviously delayed and the latest frost was far in advance from 1980's,the date of the first stronger rain in spring delayed,the times of spring drought increased,but flood years reduced,the days of spring gale day number obviously decreased.Winter warming has caused the warming house vegetable production better.General speaking,the meteorological element changes in Shenyang are to benefit to agriculture production.

• Climatic Character and Cause Analysis of Summer High Temperature in Main Cities of East China
• ZHANG Shang-yin;ZHANG Hai-dong;XU Xiang-de;ZHANG De-kuan;LIAO Yao-ming;SONG Yan-ling
• 2005 Vol. 24 (5): 829-835. 
• Abstract ( ) PDF (1202KB) ( )
• Based on the high temperature data in East China during June~August 1961-2000,the climatic character of high temperature weather in Shijiazhuang,Nanjing and Fuzhou are analyzed.The variable features of the subtropical high and reason of high temperature weather are discussed.The results show that the duration of dry-and-muggy weather during severe high temperature process at shijiazhuang station is no long,but the extreme temperature is high,daily mean wind speed and relative humidity are small;and vice versa,at Nanjin and Fuzhou stations,but for the daily mean speed and extreme temperature.In the last 40 years,the monthly mean sunshine duration has reduced in summer of East China.The subtropical high and continental denatured high are to cause the main effect system of high tempearture of damage in East China in summer,which is an important reason of the increasing of day of severe muggy high temperature weather and high temperature time in the most of cities of East China.