中文摘要：

利用珠峰北部地区的观测资料和AIRS卫星遥感资料,分析了喜马拉雅北部地区的大气日变化及其垂直结构。结果发现喜马拉雅北部地区气温日变化具有明显的单峰单谷型特征,一天气温最高值出现在18：00左右,最低值出现在早上7：00~9：00。风速的日变化呈现单峰型特征。气压的平均日变化呈双峰双谷型分布特征,气压极大值出现在2：00和12：00,气压极小值出现在6：00和19：00时,其中19：00出现气压最小值。感热通量、潜热通量的平均日变化和气温日变化具有一致性,春季感热通量大于潜热通量。净辐射通量的日变化特征是单峰型特征,每日最大值出现的时间比感热通量及潜热通量的最大值出现的时间早2个小时。引起高原地区日变化剧烈有2个主要原因：一是高原地区大气柱的质量较小,对太阳辐射的削弱较小,且相同的辐射加热和冷却可使较少大气产生较大温度变化;二是高原地区是大气云光学厚度较小的区域,由此可使地面在日间接受较强烈的太阳短波辐射而增温较大,在夜间又接受较小的大气长波逆辐射而降温较大。

英文摘要：

The observation data collected by Atmospheric and Environmental Comprehensive Observation and Research Station on Mt.Qomolangma,Chinese Academy of Sciences（AECORSQ,CAS） and the AIRS（Atmospheric Infrared Sounder） satellite data obtained during the period of from March to May of 2008 are employed to analyze the diurnal changes and the vertical features of atmosphere over the northern region of the Himalayas in spring.The results show that the diurnal mean variation of surface air temperature has one-peak-one-vale pattern.The highest temperature occurred around 18：00 Beijing local time and the lowest was between 7：00 to 9：00 Beijing local time.The diurnal mean variation of wind speed has one-peak pattern,and the air pressure has two-peaks-two-vales pattern while the lowest occurred at 19：00 Beijing local time.The diurnal mean variations of sensible heat flux and latent heat flux were consistent with the diurnal change of air temperature.The pattern looks like the net radiation diurnal pattern,but the peak time appears about 2 hours later.The sensible heating flux is stronger than latent heating flux over the Tibetan Plateau in spring.There are two main reasons which caused the remarkable diurnal variation of air temperature over the Tibetan Plateau while the mass of the atmosphere over the plateau is much less than the mass of atmosphere over other regions,and it can gain more solar shortwave radiation and less shortwave radiation while the optical depth over this region is smaller.