近地表水汽密度对多年冻土区地表辐射的影响研究——以北麓河地区为例  

Effect of near-surface water vapor density on surface radiation in permafrost regions:a case study in Beiluhe area,Qinghai province,China

作　　者：马安静 张明礼[1,2] 周志雄 王永斌 王成福 MA An-Jing;ZHANG Ming-Li;ZHOU Zhi-Xiong;WANG Yong-Bin;WANG Cheng-Fu(College of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Lanzhou 730000,China)

机构地区：[1]兰州理工大学土木工程学院,兰州730050 [2]中国科学院西北生态环境与资源研究院冻土工程国家重点实验室,兰州730000

出　　处：《气候变化研究进展》2024年第3期304-315,共12页Climate Change Research

基　　金：国家自然科学基金项目(42261028);中国科学院“西部青年学者”项目(23JR6KA027);陇原青年创新创业人才(个人)项目(张明礼)(2023LQGR18);冻土工程国家重点实验室开放基金(SKLFSE201804)。

摘　　要：气候暖湿化背景下,青藏高原地区大气水汽含量的增大通过影响地表辐射进而影响多年冻土地表能量分配及其热稳定性。以青藏高原中部北麓河地区的气象数据与活动层水热数据为基础,分析了2 m处空气相对湿度和夏季典型降雨事件对地表反照率及辐射四分量的影响。结果表明:大气水汽通过削弱太阳短波辐射,吸收地面长波辐射,增加向下长波辐射,进而降低地表反照率。大气水汽对地表辐射的影响具有明显的季节性特征,夏季大气水汽对太阳短波辐射的削弱作用最明显,并且发射的向下长波辐射较多;冬季大气水汽对太阳短波辐射的削弱作用相对较弱,发射向下长波辐射较少。在研究时段内北麓河地区夏季和冬季空气相对湿度每增加10%,太阳短波辐射日均值分别减少54.9和9.8 W/m^(2),向下长波辐射日均值分别增加14.8和3.9 W/m^(2)。秋季空气中水汽含量的变化对地表反照率的影响最大,秋季空气相对湿度每减小10%,地表反照率增加0.15;春季最小,春季空气相对湿度每增加10%,地表反照率仅降低0.01。夏季不同典型降雨事件导致近地表水汽密度和浅层土壤含水量增大,使地表反照率降低。夏季不同类型降雨事件对地表反照率的影响程度表现为:大雨>中雨>小雨。研究结果为暖湿化气候背景下青藏高原中部多年冻土区地表能量平衡分析提供参考。Under the background of climate warming and humidity increase on the Qinghai-Tibet Plateau,atmospheric water vapor is increasing.The impact of atmospheric water vapor on land surface radiation will inevitably affect the energy distribution and thermal stability of permafrost.Based on the meteorological and hydrothermal data of the Beiluhe station located in the central Qinghai-Tibet Plateau,the effects of relative humidity at the height of 2 m and typical summer rainfall events on land surface albedo and radiation components were analyzed.The results are as below.Atmospheric water vapor can effectively weaken short-wave radiation,absorb long-wave radiation from the ground,increase downward long-wave radiation,and thus reduce surface albedo.The influence of atmospheric water vapor on land surface radiation has obvious seasonal characteristics.In summer,atmospheric water vapor has the most obvious weakening effect on solar short-wave radiation,and releases more downward long-wave radiation.In winter,the weakening effect of atmospheric water vapor on solar short-wave radiation is relatively weak,and less downward long-wave radiation is emitted.During the study period,for every 10%increase in the relative humidity of the atmospheric in the Beiluhe region in summer and winter,the daily average value of solar short-wave radiation will decrease by 54.9 and 9.8 W/m^(2),respectively.At the same time,the daily average value of downward long-wave radiation will increase by 14.8 and 3.9 W/m^(2),respectively.In autumn,the change in atmospheric water vapor has the most significant impact on the surface albedo.When the relative humidity in the atmosphere decreases by 10%in autumn,the surface albedo increases by 0.15.In contrast,the impact in spring is the smallest.When the relative humidity in the atmosphere increases by 10%in spring,the surface albedo only decreases by 0.01.Different typical rainfall events in summer lead to an increase in near-surface water vapor density and soil moisture content at shallow depths,which reduc

关 键 词：多年冻土 青藏高原 空气湿度 反照率 辐射 

分 类 号：P642.14[天文地球—工程地质学] P422[天文地球—地质矿产勘探]