摘要
冻土水文过程的复杂性使其分析及模拟较为困难,在研究青藏高原冻土退化水文效应的过程中,需要明确流域内土壤冻结和融化状态的时空变化特征。利用被动微波遥感数据反演获得的地表冻融状态,系统地辨识怒江流域中上游地表冻融状态时空变异特征。结果表明:1.怒江流域贡山水文站以上年平均地表冻结天数>270 d的区域占研究区总面积的32.0%,而180~270 d的则约占62.3%,海拔高度每升高1 000 m,年地表冻结天数平均增长约62 d;2.研究区不同年份持续冻结的开始和结束时间差异较大,融化-冻结阶段的9—10月平均气温与阶段末10月地表冻结面积的相关系数为-0.80,而冻结-融化阶段的4—6月平均气温与阶段末6月地表冻结面积的相关系数则为-0.87,均在0.01水平上显著负相关,研究区气温的年际波动导致地表冻结面积、冻结日期、融化日期及冻结持续时间等的年际变化;3.被动微波遥感反演获得的高时间分辨率冻融状态数据,可为气候变化背景下,缺资料高原山地流域大范围地表冻融状态变化分析、流域尺度水文过程模拟等提供良好的数据支撑。
The complexity of hydrological process in frozen regions makes its analysis and simulation difficult.When researching on hydrological impacts of frozen soil degeneration in Tibetan Plateau,it is needed to know spatial and temporal distribution characteristics of soil freezing and thawing status. Making use of surface soil freeze/thaw status derived from passive microwave remote sensing data,spatial and temporal distribution and variation characteristics of surface soil freezing and thawing status in the Upper and Middle Nujiang River Basin was identified. The results showed that：（ 1） In much of Nujiang River Basin above Gongshan station,the area with more than 270 surface freezing days covered 32. 0% of total area,and the area with surface freezing days between 180 and 270 days accounted for 62. 3%. On average,annual surface freezing days were increased by about 62 days with every 1000 m elevation.（ 2） The start and end time of continuous freezing status in the study area varied in different years. The correlation coefficient between average temperature in thaw-freeze stage（ September to October） and freezing area in October was-0. 80,while the correlation coefficient between average temperature in freeze-thaw stage（ April to June） and freezing area in June was-0. 87. Both reach 0. 01 significant level. Interannual fluctuation of air temperature resulted in the variations of surface soil freezing area and duration,and the start date of freezing and thawing status.（ 3） Surface soil freeze/thaw status derived from passive microwave remote sensing data,with high time resolution,could be applied in large-scale freeze/thaw variations analysis and hydrological simulation under climate change,especially in ungauged plateau and mountain watersheds.
出处
《山地学报》
CSCD
北大核心
2017年第3期266-273,共8页
Mountain Research
基金
国家自然科学基金项目(41601026)
喜马拉雅地区气候变化适应性研究项目(挪威外交部和瑞典国际发展署)~~
关键词
地表冻融状态
被动微波遥感
气候变化
怒江流域
surface freeze/thaw status
passive microwave remote sensing
climate change
Nujiang River Basin
