摘要
高山冰川以其下垫面的致冷效应形成独特的冰川小气候。为研究冰川小气候特征,2007年7月在天山乌鲁木齐河源1号冰川表面及末端冰碛上架设5台自动气象站,并进行了为期一个月的基本气象要素的观测。以观测数据为基础,描述和分析了与冰川致冷效应有关的冰川区温度与湿度变化特征、冰面逆温、温跃现象、冰川风现象,并就冰川致冷效应对局地对流性降水的可能影响进行了初步分析。
Glacier microclimate comes into being when there exist mountain glaciers in temperate latitudes and they interact with surrounding environment through the glacier cooling effect.Little studies focused on the glacier cooling effect.To study the characteristics of glacier microclimates related to glacier cooling effect,especially effects on local precipitation,five Automatic Weather Stations(AWS) were established at the surface of No.1 glacier,the headwater of the Urumqi River,the Tianshan Mountains in July,2007,and basic meteorological data were collected for 30 days.The temperature and humidity characteristics and glacier cooling effect related phenomena are described and analyzed based on these data.One month observation data indicate that the existence of glacier surface has a distinct impact on local microclimate of the surrounding region,including local temperature,humidity,wind direction and convective precipitation.Temperature jump exists between glacier and non-glacier surface and the vertical temperature descending rate is-1.37 ℃/100 m from the glacial valley to the glacier tongue,which is much larger than that in free atmosphere(about 0.67 ℃/100 m).The temperature jump graduates away on the connatural surface such as glacier surface and alpine meadow.There is a distinct inversion layer between the heights of 1.5 m and 0.5 m on the glacier surface at most observation times,the average temperate at 0.5 m height is 0.67 ℃ lower than that at 1.5 m height.The inversion layer was influenced strongly by cloud covers and wind speed.Generally,it is more distinct on clear days than on cloudy or snowing days and so forth on nighttime than on daytime.The relative humidity at 1.5 m height is smaller than that at 0.5 m height above the glacier surface and it varies in different weather conditions.Wind direction statistical analyses indicate that all AWS's wind directions were influenced by glacier breeze and topography during the observation period,and the glacier breeze dominates on the glacier surface with two-AWS for whole day.In the glacial valley with two-AWS,the valley wind and glacier breeze dominate alternately in the daytime and nighttime.The glacier cooling effect has a potential influences on local convective precipitation.A cursory partition method was applied to the precipitation data of the research region and the result indicates that the more closer to the glacier,the more convective precipitation occurs.But it's a complicated phenomenon,and the influence of topography is not excluded.More meticulous and precise observation and research work is necessary to discuss this topic in depth.
出处
《干旱区地理》
CSCD
北大核心
2011年第3期449-457,共9页
Arid Land Geography
基金
中国沙漠气象科学研究基金(Sqj2006008)
中国气象科学研究院基本科研业务费专项基金(2007Y005)资助
关键词
天山乌鲁木齐河源1号冰川
小气候观测
致冷效应
No.1 glacier
Headwater of Urumqi River
Tianshan Mountains
microclimate obversation
glacier cooling effect
