祁连山西段冰川区与非冰川区气温梯度年内变化特征

Monthly variations of temperature gradient in glacierized and non-glacierized areas of the western Qilian Mountains

为研究冰川区与非冰川区不同下垫面对气温梯度的影响。本文利用祁连山老虎沟流域4180 m,4550 m和5040 m处的三个气象站及肃南、肃北、托勒、玉门、酒泉、瓜州、敦煌等七个国家气象站2011-2013年的日平均气温资料,分析了祁连山西段冰川区与非冰川区年内气温梯度特征,并结合相应时段的降水资料以及其他气象因素对其变化特征做了分析。结果表明:(1)在非冰川区,气温梯度随海拔上升而增大,且有明显的月际波动特征,年内梯度呈现先减后增的趋势,夏季最大,冬季最小,年气温梯度为0.50℃·(100m)-1;(2)在冰川区,气温梯度呈现先增后减的趋势,夏季最小,冬季最大,年气温梯度为0.61℃·(100m)-1,日内变化特征为白天气温梯度变化幅度大但值较小,夜间变化幅度小,稳定在0.83℃·(100m)-1左右,日内平均气温梯度为0.49℃·(100m)-1;(3)冰川区与非冰川区年内温度梯度与降水梯度呈相反的变化趋势,表明降水对气温梯度变化有一定的影响。(4)由于非冰川区与冰川区下垫面不同,气温梯度呈相反的年内变化趋势,在由非冰川区气温推算冰面气温时必须考虑温跃值影响,老虎沟12号冰川年平均温跃值为1.30℃。

In order to study the effect of underlying surfaces on the temperature gradient in glacierized and non-glacierized areas,in this paper,the daily mean temperature data of three meteorological stations at 4180 m,4550 m and 5040 m in the Laohugou basin of Qilian Mountains,along with seven national meteorological stations(Sunan,Subei,Toler,Yumen,Jiuquan,Guazhou and Dunhuang)are used to analyze the characteristics of annual temperature gradient in glacierized area and non-glacierized area in the western Qilian Mountains,combined with precipitation and other meteorological data.It is found that:(1)in the non-glacierized area,the temperature gradient increases with elevation and with obvious monthly fluctuation.Temperature gradient presents the trend of decreasing firstly and then increasing,with a maximum in summer and a minimum in winter,and an annual mean temperature gradient of 0.50℃·(100 m)-1.(2)In the glacierized area,the temperature gradient presents the trend of increasing first and then decreasing,with a minimum in summer,and a maximum in winter,and an annual mean temperature gradient of 0.61℃·(100 m)-1.The variation of daily temperature gradient is large in daytime with an average temperature gradient of 0.49℃·(100 m)-1 and stable at 0.83℃·(100 m)-1 at night without obvious change.(3)The annual temperature gradient has opposite to the precipitation gradient in glacierized area and non-glacierized area,indicating that precipitation has a certain effect on the change of temperature gradient.(4)Due to the difference of underlying surface between the non-glacierized area and the glacierized area,the temperature gradient has the opposite variation trend in the year.The temperature jump must be considered when the temperature on the ice surface is calculated from the non-glacierized area.The annual average temperature jump on the Laohugou Glacier No.12 is 1.30℃.