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28 December 2007, Volume 26 Issue 6   
  • Observation of Diurnal Circulation on the Northern Slope of Mt. Qomolangma
  • ZOU Han;ZHOU Li-bo;MA Shu-po;LI Peng;LI Ai-guo;HUO Cui-ping
  • 2007 Vol. 26 (6): 1123-1140. 
  • Abstract ( ) PDF (1628KB) ( )
  • The energy/matter exchange between the surface air and the troposphere is the important connection of the Tibetan Plateau and the global atmospheric systems.The great imhomogeneity in the topography and surface cover of the Tibetan mountain systems induces complicated local atmospheric circulations,and the circulations influence the exchange processes between the surface air and the troposphere over these regions.To better understand the local circulations in the Tibetan mountains,authors conducted the observational campaign HEST2006,in the Rongbuk Valley on the northern slope of Mt.Qomolangma,during May 29 and June 30,2006.In this study,the diurnal atmospheric circulation is analyzed,using the observed data,including the distribution and variation of surface wind,the vertical structure,the vertical motion,and the possible driving forces.It results in that the local circulation in this region is driven by the solar radiative heating and cooling with strong impacts of the topography and surface covers,and the local circulation is composed of various mountain circulation systems.
  • Characteristics and Analyses of Solar Radiation and Atmosphere on the Northern Slope of the Mount Qomolangma
  • BAI Jian-hui;ZOU Han;LI Ai-guo;MA Shu-po;JIA Jing-jing;LI Peng;WANG Wei;HUO Cui-ping
  • 2007 Vol. 26 (6): 1162-1172. 
  • Abstract ( ) PDF (975KB) ( )
  • Solar global radiation,net radiation,temperature,humidity,and wind were measured on the north slope of the Mount Qomolangma from May 27 to June 30,2006.3 stations were set up alone with the north slop of the Qomolangma,the measured radiation,temperature,wind showed an evident diurnal variation at 3 stations,and reached their daily maximums of changing rates at 08:00,09:00,respectively.Solar global and net radiation displayed similar diurnal pattern.For the beginning time of daily maximum,radiation is earlier than temperature,and temperature earlier than wind speed for all stations.The ratio of daily maximum of radiation including global and net radiation and the ratio of daily maximum of temperature and wind speed for any 2 stations were closer.For monthly averaged diurnal variation,wind direction in the region far away from the Qomolangma was changed several times during a day,but wind direction in the region near the Qomolangma wasn't changed,and was south wind all the time,which was caused by the difference of radiation,geological structure,air temperature,and etc.The change of wind(including direction and speed) alone valley on the north slop of the Qomolangma exhibited an obvious time lag,and south wind was stronger the north wind,and persisted longer time.Radiative energy plays an important driving role on the motion of the atmosphere on the north slop of the Qomolangma,and is the most basic and important factor to control and change the motion manner of the atmosphere.Net radiation plays a critical role in the processes of the changing of wind direction and speed at different regions.
  • Impacts of the South Asian Summer Monsoon on Variations of Surface Wind on the Northern Slope of Mt. Qomolangma
  • ZHOU Li-bo;ZOU Han;MA Shu-po;LI Peng;WU Rui-huan
  • 2007 Vol. 26 (6): 1173-1186. 
  • Abstract ( ) PDF (2007KB) ( )
  • The Himalayas is near the South Asian monsoon region,with a special local circulation system induced by its steep topography and complex terrains.For better understanding the circulation system and its possible relationship with the weather pattern over the South Asian regions,we analyzed the variation of surface wind in the Rongbuk valley on the northern slope of Mt.Qomolangma and its responses to the South Asian summer monsoon(SASM),using the observation data obtained during HEST2006 campaign in June 2006 and real-time atmospheric circulation data.During the weak SASM period,the Himalayan regions are mainly dominated by clear days,and the northward surface wind prevails in the Rongbuk valley with a strong solar radiation;while during the strong SASM period,the surface wind and the solar radiation in the Rongbuk valley becomes weak,and the Himalayan regions are mainly controlled by the cloudy and rainy weather conditions.The analyszd result showed that the local circulation in the Rongbuk valley has little responses to the atmospheric circulation at the upper levels,but is closely related to the solar radiation flux and SASM index.Therefore,we concluded that the SASM could have impacts on the Himalayan surface circulation by changing the local thermal and radiation conditions.
  • Vertical Temperature Observation in the Rougbuk Valley on the Northern Slope of Mt. Qomolangma
  • LI Peng;LI Ai-guo;JIA Jing-jing;ZOU Han
  • 2007 Vol. 26 (6): 1254-1262. 
  • Abstract ( ) PDF (1066KB) ( )
  • The Qinghai-Xizang Plateau and its unique dynamic thermal effect influences the East Asian region as well as global weather,climate and environmental change process.Steep terrain and diverse state of the surface cause the complex circulation system and the boundary layer characteristics.During May 28 to June 30,2007,the Institute of Atmospheric Physics and the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences organized and implied the tropospheric atmosphere exchange research(HEST2007) on North Slope region in the Himalayas surface observation experiments to Study the local atmosphere circulation system of the mountains on the Qinghai-Xizang Plateau.In this Study,the virtual temperature obtained from LAP-3000 is converted to temperature,by using other observed data,and the vertical distribution of temperature and its changes are preliminary analyzed.The analysis shows the obvious differences is existed between the virtual temperature and the real temperature,the differences can be effectively decreased through the inversion,the vertical distribution of temperature is significantly different between the morning and afternoon in the Rougbuk valley.
  • The Rainy Season Character of Troposphere at Mt. Qomolangma Region
  • CHEN Xue-long;MA Yao-ming;SUN Fang-lin;LI Mao-shan;WANG Shu-zhou
  • 2007 Vol. 26 (6): 1280-1286. 
  • Abstract ( ) PDF (903KB) ( )
  • Using the data of Atmospheric Boundary Layer(ABL) tower,radio sonde and wind profiler set up on the Comprehensive Observation and Research Station of Qomolangma,Chinese Academy of Sciences,lower layer atmosphere characteristics(wind speed,wind direction,air temperature,potential temperature and air humidity etc.) during the rain season were analyzed in this paper.Wind speed,wind direction and temperature near surface have obvious diurnal variations.For the wind direction,it is divided into two phase,one blow nearly north wind derived by Valley wind,the other blow nearly south wind derived by Glacier wind.The change time is 14:30.The diurnal Glacier wind is stronger than the nightly valley wind.Maybe vertical shear of horizontal wind is one important reason for precipitation in this region.The low level jet is familiar during summer.Averaged temperature digression of troposphere is 0.685K/100m.The vapor content in the air of lower atmosphere has two peak,the maximal vapor content height is blow 4000 m,the next peak is not fix.The relative humidity up than 16000 m cannot exceed 10%.Each layer has different wind speeds and directions.