基于合成孔径雷达图像的山区雪水当量反演

Retrieval of snow water equivalence using SAR data for mountainous area

雪水当量是表征积雪水资源量的重要指标,准确获取雪水当量信息对于流域水资源管理与区域气候研究具有重要意义.以新疆玛纳斯河流域山区典型地区为研究区,在获取RADARSAT-2精细四极化产品、地面同步观测数据、数字高程数据和土地覆盖类型数据的基础上,探讨了针对山区地形与下垫面条件的EQeau模型参数优化方法,修订了模型系数,并反演获得了研究区2013年12月13日的雪水当量分布信息.结果表明:(1)在山区复杂地形与下垫面条件下,增加地形、土地覆盖类型和局部入射角作为EQeau模型的条件参数,可取得冬秋季后向散射系数比与积雪热阻间较好的拟合关系,从而修订模型系数;(2)利用系数修订后的EQeau模型和RADARSAT-2数据反演得到了研究区精度较高的雪水当量信息,进而表明利用C波段合成孔径雷达数据和EQeau模型反演山区雪水当量是有效可行的.研究成果可为山区雪水当量的定量反演提供新思路.

Snow water equivalence（SWE）is an important indicator to characterize the amount of snow water resource.The acquisition of SWE has important significance in water resource management in river Basin and regional climate research.In this study,we chose a typical area of Manasi River Basin in Xinjiang Province as the research area,obtained the RADARSAT-2Fine Quad-Pol products,ground synchronous measurement data,digital elevation data andland cover data.Based on these data,we discussed the parameters optimization method of EQeau model for mountainous terrain and underlying surface conditions,revised the model coefficients,and eventually retrieved the SWE distribution information of study area at December 13,2013.The results showed that：（1）Under the mountainous terrain and underlying surface conditions,increasing the topography,land cover types and local incidence angle as the parameters of EQeau model could get better fitting relationship between the backscatter coefficient ratio and snow thermal resistance;（2）the high precision of retrieval result indicated that the SWE retrieval by using C-band SAR data and EQeau model for mountainous area was feasible and effective.This research can provide ideas for solving quantitative inversion of mountainous SWE.