珠穆朗玛峰地区气象要素特征观测研究

Observational Study on Characteristics of Meteorological Elements in Mountain Qomolangma Region

利用中央气象台奥运火炬传递珠峰气象保障队获取的第一手资料,对2007年4月12日-5月8日珠穆朗玛峰(简称珠峰)大本营地面自动站和79次探空实测资料进行分析,揭示了珠峰地区气象要素变化的观测事实。结果表明:受珠峰北坡绒布冰川沉降风影响,珠峰大本营盛行南风;风速和气温日变化呈单峰分布,风速极小值和日最低气温出现在08:00(北京时,下同),而极大值出现在15:00前后;相对湿度峰值出现在07:00和23:00,正午前后相对湿度最小。6200 m高度以下几乎昼夜恒吹下山风,偏南风在22:00至次日00:00最强;7200-9000 m高度风向主要以偏西风为主,风速随高度也明显增加。5200-8000 m各高度上,日最低气温始终出现在08:00,最高气温出现在16:00,8200 m以上气温呈现出多波动起伏。在6700-9700 m高度能维持相对湿度的高值中心,大值区主要位于6500-8800 m高度。高空西风锋区位于12000-15000 m,对流层顶高度大约在18200 m左右。

The Qomolangma Olympic torch relay meteorological guarantee team of the Central Meteorological Office has obtained precious first-hand observational data,including in-situ data of automatic station and 79 sounding data in the Qomolangma＇s base camp from 12 April to 8 May in 2007.Observational characteristics of meteorological elements in Mountain Qomolangma are revealed in terms of these data and the results are as follows. Due to the effect of glacier wind in Rongbuk Valley,the prevalent wind is a downslope wind（south wind） in the Qomolangma＇s base camp.The diurnal changes of wind speed and temperature show single-peak type distribution,with the minimum appearing at 08：00 and the maximum at 15：00.Relative humidity peaks appear at 07：00 and 23：00,the minimum at noon.There is a constant south wind below 6200-meter elevation,and the strongest downslope-wind happens during 22：00—00：00.West wind is dominant for 7200—9000 meters,and its speed increases significantly with the elevation.At the height of 5200--8000 meters,the temperature always reaches minimum at 08：00 and maximum at 16：00,but the temperature diurnal change shows more fluctuations above 8200 meters.The high value centers of relative humidity can maintain at an elevation of 6700—9700 meters,and the highest value areas locate mainly in 6500—8800 meters.From late April to early May,the high-level frontal zone in the Everest area is at the elevation of 12000—15000 meters,and troposphere top height is around 18200 meters.Rising temperature,pressure and decreasing wind speed offer ideal time window for climbing the mountain.