多源遥感产品在黄土丘陵沟壑区土壤水分反演中的适用性评估

Adaptability Evaluation of Multi-source Remote Sensing Products to Soil Moisture Retrieval in Loess Hilly and Gully Region

黄土丘陵沟壑区是黄土高原水土流失最为严重的地区,土壤水分的长期精准监测对该区域生态环境的修复、农业的高质量发展有重要的现实意义.以站点实测土壤水分作为参考数据,利用R、RMSE、Bias、ubRMSE作为评价指标,对比分析了土壤水分产品SMAP、AMSR2、GLDAS在黄土丘陵沟壑区不同地形条件下的具体表现,并根据研究结果选出精度最高的土壤水分产品对黄土丘陵沟壑区2016~2021年的土壤水分进行时空分析.研究表明,(1)在丘陵坡耕地、平原谷地、河滩地3种地形条件下,SMAP土壤水分产品在各项评价指标中都要优于AMSR2、GLDAS,其适用性最优;(2)2016~2021年黄土丘陵沟壑区土壤水分整体呈上升趋势.2016~2021年4季以及多年平均土壤水分呈现东、西部地区土壤水分较多,中部地区土壤水分较少的空间分布格局.

The loess hilly and gully region is the most serious area of soil and water loss on the Loess Plateau.The long-term and accurate monitoring of soil water has important pracitcal significant for the restoration of the ecological environment and high-quality development of agriculture in the region.The paper,takes the measured soil moisture as the reference data,and R,RMSE,Bias,and ubRMSE were used as the evaluation indicators to compare and analyze the specific performance of soil moisture products SMAP,AMSR2 and GLDAS under different topographical conditions in the loess hilly and gully region.According to the research results,the soil moisture products with the highest accuracy were selected to conduct spatio-temporal analysis of soil moisture in the Loess hilly and gully region from 2016 to 2021.The results showed that:(1)SMAP soil moisture products was better than AMSR2 and GLDAS in all evaluation indexes under the three terrain conditions of hilly and sloping farmland,plain and valley,and tidal land,and its applicability was the best.(2)From 2016 to 2021,soil moisture in the loess hilly and gully region showed an increasing trend.From 2016 to 2021,four seasons and multi-year average soil moisture showed a spatial pattern of more soil moisture in the eastern and western areas,and less soil moisture in the central area.