Current Issue

• Prediction of Annual Average Temperature Change along Qinghai-Xizang Railway
• LI Dong-liang;GUO Hui;WANG Wen;WEI Li
• 2003 Vol. 22 (5): 431-439. 
• Abstract ( ) PDF (2055KB) ( )
• The annual average temperature of the stations along Qinghai-Xizang railwaycorrelated well each other,especially the correlationof 10-year running average series of them is 0.92.According to the result,the annual averagetemperature series along Qinghai-Xizang railway( T _rw) from 1935 to 2000 are constructed.The results show that there is notable response between T _rw and the sunspot cycle length(SCL) and atmospheric carbon dioxide concentrations(CO ₂) with lagging 5 and 15 years,respectively.The correlation coefficient between them respectively is -0.76(SCL) and 0.88(CO ₂).Using 76 a,93 a,108 a,205 aand 75 a significant cycle of SCL and the model of mean generating function,the fast and slow periods of the future SCL is predicted,and the values of SCL in the former 50 years in 2000 will be higher as a whole,and will be lower in the latter 50 years.Considering double CO ₂ concentrations and the climatic change, T _rw of 21 ^st century is forecasted to warm up about 0.5℃ as compared with the last 10 years in 20 ^th century(1990's),and about 1.0℃ as compared with the last 30 years of 20 ^th century(1971-2000).

• The Standard of Marking off the Four Seasons along Qinghai-Xizang Railway and Its Temperature Variation Analysis
• TANG Mao-cang;ZHONG Hai-ling;LI Dong-liang
• 2003 Vol. 22 (5): 440-444. 
• Abstract ( ) PDF (1679KB) ( )
• We discussed the standard of marking off the four seasons in the Qinghai-Xizang Plateau,and we think if using the daily average temperature as the index,we should reduce the standard of Zhangbaokun by 5℃ which fits the East China.We mark off the beginning date of the four seasons according to 40 year data of the seven meteorology stations and Wenquan data of 6 years.It found that Golmud and Lhasa have transitory summer,but the main body of the Plateau has no summer between spring and autumn.The area near the mouth of Kunlun mountain has only winter.The temperature varying with the latitude in the Plateau is similar to that in the Plain of East China,The temperature gradient is big in winter and small in summer.The inversion layer in Chaidamu basin is the thickest,which become gradually thinner toward south.

• Tree-Ring Chronology in Southern Qinghai and Its Relation to Climatic Element
• QIN Ning-sheng;SHAO Xue-mei;SHI Xing-he;JIN Li-ya;ZHU Xi-de;WANG Qing-chun
• 2003 Vol. 22 (5): 445-450. 
• Abstract ( ) PDF (1022KB) ( )
• Based on the tree-ring chrionology samples collected in Qumalai and Zhiduo of southern Qinghai plateau,the tree-ring chronology in southern Qinghai is established.The calculated result of response function shows that the tree ring variation was more sensitive to local maximum temperature and evaporation from April to June in spring.Historical maximum temperature in spring was reconstructed from tree-ring data.

• Climatic Change over Qinghai and Xizang in 21 ^st Century
• XU Ying;DING Yi-hui;LI Dong-liang
• 2003 Vol. 22 (5): 451-457. 
• Abstract ( ) PDF (361KB) ( )
• Scenario of surface air temperature(Ts) and precipitation(Pr) changes in Qinghai and Xizang due to effects of human activities in 21 ^st century was studied based on the simulations of seven atmosphere-ocean coupled models(AOGCMs)(CCC,CCSR,CSIRO,DKRZ,GFDL,HADL,NCAR).The simulated results showed that the warming air temperature is more obvious in Qinghai and Xizang than whole Chinaby both increasing of greenhouse gases(GG) and increasing of greenhouse gases plus sulfate aerosol(GS).The warming range is 2.8~3.0℃ Kalong Qinghai-Xizang railway stations in middle of 21 ^st centary,and 3.8~4.8℃ in the end of 21 ^st century.The increasing of minimum temperature in the winter and maximum temperature in the summer is more than annual mean temperature.The precipitation will increasein the 21 ^st century.

• Numerical Simulation for Influence of Greenhouse Effects on Climatic Change of Qinghai-Xizang Plateau along Qinghai-Xizang Railway
• GAO Xue-jie;LI Dong-liang;ZHAO Zong-ci;Filippo Giorgi
• 2003 Vol. 22 (5): 458-463. 
• Abstract ( ) PDF (856KB) ( )
• Climatic change due to greenhouse effects(2×CO ₂) over Qinghai-Xizang Plateau,with focus on the area along Qinghai-Xizang railway simulated by a regional climate model(RegCM2) have been investigated.The model was nested to a global coupled ocean-atmosphere model(CSIRO R21L9 AOGCM).Analysesof controlrun of the regional model indicatedthat it can reproduce the climate betterthan the global model in the area.Results of sensitive experiment by the regional modelwith 2×CO ₂ showed that the surface air temperature over the areamight increase remarkably due to greenhouse effect.The value are usually greater than 2.6~2.8℃,which is higher than that in China.Precipitationmight also increase over most of the area.Increasing precipitation along Qinghai-Xizang railway are usually greater than 25%,which is higher than in China.Daily maximum and minimum temperaturewill also increase in the area.

• Decadal Temperature Changes over Qinghai-Xizang Plateau in Recent 50 Years
• CAI Ying;LI Dong-liang;TANG Mao-cang;BAI Chong-yuan
• 2003 Vol. 22 (5): 464-470. 
• Abstract ( ) PDF (1330KB) ( )
• Based on the monthly temperature data of more than 100 stations over Qinghai-Xizang Plateau and its neighboring regions from 1950's to the end of the twentieth century,utilizing statistical methods,the decadal temperature change in these regions in recent 50 years were analyzed.The results showthat the temperature variations over Plateau were divided into 6 subregions.On the temporal variation,there are two relatively warm phases(before 1963 and after 1987 respectively) interrupted by a relatively cold phase(1963-1987).The possible reasons for temperature change overPlateau were discussed from the astronomical factor and the interaction among the components of the climate system.

• Numerical Simulation of Freezing Soil Process on Qinghai-Xizang Plateau in Early Winter
• ZHANG Yan-wu;Lü Shi-hua;LI Dong-liang;Huang Jing
• 2003 Vol. 22 (5): 471-477. 
• Abstract ( ) PDF (1169KB) ( )
• Using the improvedparameterization schemes of freezing and melting soil processes in NCAR MM5 atmosphere model coupling NCAR LSM land surface model and the NCEP reanalysis data from October 2 to 30,2001,the numerical simulation experiment in Qinghai-Xizang railway-line region was carried out.The influence of soil folw-off and infitration on the hydrological process of soil was improved in the new scheme,the resolution of ice content was added,so that the model can really reflect the soil freezing and melting processes.The results show that after improved freezing and melting soil schemes,the model has shown some improvements in the simulation of soil temperature and surface flux,and it can reflected the change of land surface element during the early period of soil freezing.

• Evaluation of NCEP/DOE Surface Flux Data over Qinghai-Xizang Plateau
• WEI Li;LI Dong-liang
• 2003 Vol. 22 (5): 478-487. 
• Abstract ( ) PDF (1456KB) ( )
• The monthly mean surface flux of NCEP/DOE reanalysis data were evaluated by comparing with the surface air temperature at meteorological stations and the surface radiation data observed during the period of August 1982 to July 1983.The results show that the annual variations of the reanalyzed temperature and radiation fluxes are very well agreed with the observations.The reanalyzed temperature are,however,systematically lower than the observation over Plateau.And it causes the reanalyzed surface downward and upward long-wave radiation flux much lower than the observations.The reanalyzed surface albedo is higher,and it causes the net solar radiation flux and total net radiation flux lower than the observation on the areas where snow is covered in winter.The deviation of temperature is mainly resulted from the difference of the reanalysis model orography and the height of station in snow-free area and seasons.The other part of deviation of temperature is resulted from the reanalysis lower net radiation flux by using higher albedos on snow-cover plateau in winter

• Reliability of NCEP/NCAR Reanalysis Data in Climatic Change along Qinghai-Xizang Railway
• WEI Li;LI Dong-liang
• 2003 Vol. 22 (5): 488-494. 
• Abstract ( ) PDF (1186KB) ( )
• The reliability of NCEP/NCAR reanalysis data in the climate change of Qinghai-Xizang railway line has been investigated by comparing with the observation data from 8 surface meteorological stations.The results show that the annual variation of surface air temperature and precipitation are very well presented through NCEP/NCAR reanalyzed data.The interannual variations of the air temperature at surface are quite well given from NCEP/NCAR reanalysis data.The reanalyzed temperature is more confidence than the reanalyzed precipitation.The results are better in summer than in winter and better in major part of Qinghai-Xizang railway line than at the two ends of the line.The trends of the surface air temperature analyzed by NCEP/NCAR,however,are completely different with those observed at the surface stations.The trends of the precipitation analyzed by NCEP/NCAR have been showed somehow comparable with the observation.It should be reminded that the NCEP/NCAR reanalyzed temperature values are systematically lower than the observation,but precipitation values higher than the observation.

• Probability Estimation for Prediction of Extra Long-Range Climatic Variation along Qinghai-Xizang Railway
• WANG Wen;LI Dong-liang
• 2003 Vol. 22 (5): 495-498. 
• Abstract ( ) PDF (962KB) ( )
• The air temperature series of annual average along Qinghai-Xizang railway reconstructed in reference[9] ranged from 1935 to 2000,thousand year SCL and the concentration of CO ₂ during 1920 to 2000 were analysed,the results showed that the frequency of positive air temperature anomaly was a little bit more than the negative one along Qinghai-Xizang railway,and the frequency of positive SCL anomaly was more than the negative one.But the frequency of nagetive anomaly of CO ₂ was much higherthan the positive one.As an experiment,using the REEP method,the increasing temperature probability along Qinghai-Xizang railway was analyzed comparing with 1990s on the basis of the predicted decadal average temperature.The results showed that the probability of increasing air temperature about 0.5℃ in 2050 is 0.64~0.73,and that about 1.0℃ in 2100 is 0.45~0.64.

• Climatic Forecast over Qinghai-Xizang Plateau Made Using Fussy Mean Generating Function(FMGF) Model
• DONG An-Xiang;LI Dong-Liang;GONG Jian-Fu;ZHANG Kun
• 2003 Vol. 22 (5): 499-502. 
• Abstract ( ) PDF (174KB) ( )
• Using running Ttest and fussy mean generating function(FMGF) model,climatic variation over Qinghai-Xizang Plateau in recent 620 years is studied and climatic forecast is made.The results showed that it is the coldest in the middle of 17th century and the warmest in 20th century.There are 31~45 year periods.Comparing with the value in 1971-2000,the temperature will be above 0.5℃ in the future 50 years.

• Estimation about Extreme Value of Air and Ground Temperature along Qinghai-Xizang Railway
• DONG An-Xiang;BAI Hu-zhi;LI Dong-Liang;XUE Wan-xiao
• 2003 Vol. 22 (5): 503-506. 
• Abstract ( ) PDF (1264KB) ( )
• Using the Gumber distribution function,the estimation values of the extreme air temperature and 0 cm ground temperature of 7 stations in Qinghai-Xizang railway in recent 620 years are studied.The results showed that the estimated value of annual extreme maximum air temperature of once every 50 years will be almost the same as normal,and for once every 100 years,above 0.1~1.5℃ than normal.The estimated value of annual extreme maximum ground temperature of once every 50 years will be above 0.0~10.2℃ than normal,and for once every 100 years,above 1.5~13.7℃ than normal.If year mean temperature will increase 1℃ from now on 50 years,the estimated value of annual extreme maximum air temperature of once every 50 years will be above -0.1~2.0℃ than normal,and for once every 100 years,above 0.7~2.8℃ than normal.

• Analyses on Air Temperature and Its Abrupt Change over Qinghai-Xizang Plateau in Modern Age
• MA Xiao-bo;LI Dong-liang
• 2003 Vol. 22 (5): 507-512. 
• Abstract ( ) PDF (764KB) ( )
• Monthly mean temperature,monthly mean maximumand minimum temperature of 84 stations in Qinghai-Xizang Plateau from beginning to 2001 are analyzed.The results show that standardized annual mean temperature increase at rate 0.21~0.42/10a;the rate of minimum temperature increase by 1~3 times maximum temperature.Daily Temperature Range(DTR) decrease significantly at rate -0.08~-0.51/10a.The abrupt changes of temperature can be found mostly in 1980's,in which Northern Hemisphere mean temperature increased significantly after 1988.The abrupt change of mean temperature began in Chaidamu(1973),maximum,minimum temperature and DTR begin in east Qinghai-Xizang Plateau,Chaidamu and south Qinghai-Xizang Plateau respectively.

• Accuracy Test on Summer Temperature Prediction in Qinghai Section along Qinghai-Xizang Railway
• SHI Xing-he;QIN Ning-sheng;TANG Hong-yu;ZHOU Lu-sheng;ZHAXI Cairang;ZHU Xi-de;DAI Sheng
• 2003 Vol. 22 (5): 513-517. 
• Abstract ( ) PDF (1218KB) ( )
• Using the summer temperature(substitute data) of Qinghai-Xizang Plateau,sunspot number,and annual average temperature at Xining,Qinghai,as well as summer temperature of Qinghai section along Qinghai-Xizang railway,we obtained the summer temperature prediction in 1991-2000 for that reagion.The qualitative and quantitative scores of the optimum subset is higher than that using periodic extrapolation,but lower than that using mean generating function.Averge score of periodic extrapolation,mean generating function,and optimum subset forecast is 60%~67%,80%,and 67.5%,respectively.For quantitative forecast with error ≤1.0℃ is 40%~57%,77.5%~82.5%,and 70%~72.5%,respectively.

• Winter Temperature of Tuotuo River Reconstructed Using Tree-Ring Chronology of Wulan
• WANG Qing-chun;ZHOU Lu-sheng;QIN Ning-sheng;LI Lin;ZHU Xi-de;WANG Zheng-yu
• 2003 Vol. 22 (5): 518-523. 
• Abstract ( ) PDF (1217KB) ( )
• Using the multiple samples of tree-ring chronology at Walan and the way and method of air temperature reconstructed in January~March of winter at Tuotuo river,800-year air tempearture series at Tuotuo river were reconstructed.The results showed that the main cold and warm periods of winter air temperature series reconstructed were basicilly coincided with the obtained results.These cold periods existed in thirteenth,fifteenth and seventeenth centuries,and warm periods,in fourteenth and sixteenth centuries.The cold period in seventeenth century was stronger in intensity and lasted a longer time yet.Some preliminary statistic analysis was used to study temperature series's variance stage,jump change and variance period,and it provide the background data for the climatic change along Qinghai-Xizang railway.

• Study on Temperature Variations and Its Anomaly Patterns over Qinghai-Xizang Plateau
• LI Lin;ZHU Xi-de;QIN Ning-sheng;WANG Zheng-yu;WANG Qing-chun;ZHOU Lu-sheng
• 2003 Vol. 22 (5): 524-530. 
• Abstract ( ) PDF (322KB) ( )
• Using 30-year annual average,maximum and minimum air temperature data from 81 weather stations in Qinghai-Xizang Plateau and EOF,REOF,climatic linear trend and accumulated variance analysis methods,the spatial and temporal annual temperature variations and temperature anomaly patterns were analyzed.The main resoults show that the annual average,maximum and minimum air temperature over Qinghai-Xizang Plateau have a good consistency,but the differences exist in south-north and east-west distribution.The large topography,especially main mountain run from east to west in Plateau has obvious effect on the spatial distribution of air temperature.There is obvious ascending tendency for the interannual change,and the sudden change of temperature has occurred in the middle and late in 1980s.The anomaly patters of temperature were effected by the topography and cold air activities obviouly.