The Impact of Local Acquisition Time on the Accuracy of Microwave Surface Soil Moisture Retrievals over the Contiguous United States

Remote Sensing

Fangni Lei²  Wade T. Crow¹  Huanfeng Shen²  Robert M. Parinussa⁴  Thomas R. H. Holmes¹  Nicolas Baghdadi³ 

[1] USDA ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA; E-Mails:;School of Resource and Environmental Sciences, Wuhan University, Wuhan 430072, China; E-Mail:;School of Resource and Environmental Sciences, Wuhan University, Wuhan 430072, China; E-Mail;Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia; E-Mail:

关键词: remote sensing;    soil moisture;    acquisition time;    retrieval algorithm;    data merging;   

DOI  :  10.3390/rs71013448

来源: mdpi

【 摘 要 】

Satellite-derived soil moisture products have become an important data source for the study of land surface processes and related applications. For satellites with sun-synchronous orbits, these products are typically derived separately for ascending and descending overpasses with different local acquisition times. Moreover, diurnal variations in land surface conditions, and the extent to which they are accurately characterized in retrieval algorithms, lead to distinct systematic and random error characteristics in ascending versus descending soil moisture products. Here, we apply two independent evaluation techniques (triple collocation and direct comparison against sparse ground-based observations) to quantify (correlation-based) accuracy differences in satellite-derived surface soil moisture acquired at different local acquisition times. The orbits from different satellites are separated into two overpass categories: AM (12:00 a.m. to 11:59 a.m. Local Solar Time) and PM (12:00 p.m. to 11:59 p.m. Local Solar Time). Results demonstrate how patterns in the accuracy of AM versus PM retrieval products obtained from a variety of active and passive microwave satellite sensors vary according to land cover and across satellite products with different local acquisition times.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.