2005年5～7月珠穆朗玛峰北坡海拔6523m气象要素特征

Meteorological Features at 6 523 m a.s.l.on the North Slope of Mt.Qomolangma from May 1 to July 22 in 2005

依据2005年第4次珠穆朗玛峰地区综合科学考察队在北坡海拔6523m处设立的自动气象站资料，分析了5月1日～7月22日的气温、相对湿度、饱和水汽压、气压和风等气象要素每10min和日记录的观测资料．结果表明，温度和饱和水汽压的平均日变化均为单峰单谷型，相对湿度平均日变化为单谷型，气压平均日变化为双峰双谷型，风速平均日变化呈现不对称的单峰型．在观测的83d中，温度、相对湿度、饱和水汽压和气压在波动中逐渐增大，而风速不断减小，风向由南风逐渐向北风转变；相对湿度和饱和水汽压的变化幅度大，并有明显的局部差异性．与1960年5月份相比，2005年5月份的候平均温度、候最高温度和候最低温度都明显下降．

An automatic weather station was set up on April 27 2005 at the Ruopula Pass （6 523 m a. s. l. ） on the northern slope of Mt. Qomolangma （Everest） by the team of integrated scientific expedition to Mt. Qomolangma. In this paper the meteorological features were analyzed based on the 10-minute-averaged and 24- hour records of air temperature, relative humidity, saturated vapor pressure, air pressure and wind from May 1 to July 22 in 2005. It is shown that at 6523 m a.s. 1. of Mt. Qomolangma, these meteorological elements display very obvious diurnal variations, and the averaged diurnal variation was one-peak-one-vale for air temperature and saturated vapor pressure, onevale for relative humidity, two-peak-two-vale for air pressure, and one-peak in an asymmetrical way for wind speed. In the 83 days, all the air temperature, relative humidity, saturated vapor pressure and air pressure increased with some fluctuations, while wind speed decreased gradually, and frequency of calm＂ wind went up and wind direction turned from north to south. Variations of relative humidity and saturated vapor pressure have great fluctuation and obvious local difference. Finally, the reasons of the diurnal and daily variations are discussed. Compared with the records of May in 1960, the 5-day maximum, minimum and averaged values of air temperature in May 2005 were apparently lower.