基于RS的昆仑山区夏季雪线高程变化及其影响因素分析

Analyses of variation of summer snowline elevation and its influencing factors in the Kunlun Mountains based on RS, 2001-2015

以昆仑山区为研究区域,利用2001-2015年MOY10A1/MOD10A1以及气温、降水等数据,通过统计学的方法得出了研究区的研究日期,积雪持续时间比率法提取了研究区近15年雪线高程,线性趋势法分析了近15年研究区雪线高程的动态变化,相关分析法研究了雪线高程变化的影响因素。经分析得出:研究日期确定为每年的7月22日-8月24日(第203~236天),共计34天,积雪持续时间比率法提取的雪线阈值为76.5%。2001-2015年昆仑山区及各区域雪线高程呈波浪式上升的趋势,昆仑山东、中、西段雪线高程变化的倾向率分别为80 m·(10a)-1、 131 m·(10a)-1和155 m·(10a)-1,昆仑山东段雪线高程变化最为稳定,其次是昆仑山中段,最不稳定的则是昆仑山西段。近15年昆仑山东、中、西段雪线高程的平均值分别为4 990 m、 5 271 m和4 936 m,并且昆仑山中段雪线高程的最小值要高于其它两区域的最大值,因此,昆仑山区域雪线高程分布特征为:中间高,两边低。从年的时间尺度分析,影响昆仑山区及各区域雪线高程变化的主控因素为气温;从季节的时间尺度分析,气温对雪线高程影响最大的季节为夏秋季,降水对其影响最大的季节则在夏冬季;从月的时间尺度分析,昆仑山区夏月气温对雪线高程影响最大,而降水对其影响最大的月份则在冬月。

In this paper,the Kunlun Mountains is taken as the research object,and MOY10 A1/MOD10 A1 of moderate resolution imaging spectroradiometer and temperature,precipitation and other data from 2001 to 2015 are used to obtain the research date in this area.Using the snow cover duration ratio method,the snowline elevation and linear trend in the research area in the period is extracted.The variation of snowline elevation in the research area is analyzed by the method of correlation analysis.According to the analysis,the research date was determined as July 22~august 24(the 203 th^236 th day)of each year,a total of 34 days,and the snowline threshold extracted by the snow cover duration ratio method was 76.5%.From 2001 to 2015,the snowline elevation in the Kunlun Mountains and other regions showed a wave rising trend.The trend rate of snowline elevation changing in the eastern,meddle and western sections of the Kunlun Mountains was 80 m·(10 a)-1,131 m·(10 a)-1 and 155 m·(10 a)-1,respectively.The eastern section was the most stable,followed by the middle section and the western section of the mountain was the most unstable.In the 15 years,the average snowline elevation in eastern,middle and western sections of the mountains was 4 990 m,5 271 m and 4 936 m,respectively,and the minimum snowline elevation in the middle section was higher than the maximum snowline elevation in other two sections.Therefore,the distribution characteristics of snowline elevation in the mountains were as follows:middle high,both sides low.From the yearly time scale analysis,the main controlling factor of the change of snowline elevation in the Kunlun Mountains and each section was air temperature.According to the time seasonal scale analysis,the seasons with the greatest influence of temperature on snowline elevation were summer and autumn,while the seasons with the greatest influence of precipitation were summer and winter.According to the monthly time scale analysis,the summer temperature in the mountains had the largest influence on the snowline elevation,while the winter precipitation had the largest influence on the snowline elevation.