青藏高原纳木错气象要素变化特征

Variation Features of Meteorological Elements at Namco Station, Tibetan Plateau

依据中国科学院纳木错综合观测研究站设立的自动气象站和气象塔观测（30°46．44′N，90°59．31′E，4730ma．s．l．）资料，初步分析了2005年7月14日至2006年7月13日一年的气温、气压、相对湿度、降水和风等气象要素的季节和日变化特征。结果表明：纳木错站年平均气温为0℃，最冷月为12月，最热月为7月；全年降水量为281．8mm，多集中在5—10月；年平均相对湿度为52．6％，雨季和干季分明，全年夜雨率为78．6％；年平均气压值为571、2hPa，9月最大，1月最小；年平均风速为4m·S^-1，1月风速最大为6．1m·S^-1，上午风弱、午后风强；全年大风日数为53天，1月大风日数占全年的36％；全年盛行风处在东南至西风（135°--270°）之间，夏季有明显的湖陆风。

According to the climatic data from an automatic weather station （AWS） and the meteorological tower at Namco Station （30°46.44＇N, 90°59.31＇E, 4730 m asl. ） during July 14,2005 to July 13,2006, seasonal and diurnal variations of air temperature, air pressure, relative humidity, precipitation, wind speed and wind direction were analyzed. Some preliminary knowledges on climatic features of this area were obtained.. The average annual temperature is 0℃, the minimum temperature appears in December and the maximum temperature in July. The annual rainfall is 281.8 mm, mainly taking place from May to October. The average annual relative humidity is 52.6 %, and the wet and dry seasons are distinct, the precipitation happening at night （20 ： 00- 8：00） accounts for 78.6% of the total. The average annual air pressure is 571.2 hPa, the minimum pressure occurs in January and the maximum pressure in September; Mean annual wind speed is 4 m·s^-1, the maximum wind speed occurs in January （6.1 m·s^-1）, there are strong winds in the afternoon and weak winds in the morning. The annual gale days are 53 d, and 36 % of it happens in January. The dominant wind direction is from SE to S（ 135°- 270°） ,wind cycle between the land and lake area is remarkable in summer.