An assessment of the differences between spatial resolution and grid size for the SMAP enhanced soil moisture product over homogeneous sites

REMOTE SENSING OF ENVIRONMENT

卷:207

Article

Colliander, A.¹  Jackson, T. J.²  Chan, S. K.¹  O'Neill, P.³  Bindlish, R.³  Cosh, M. H.²  Caldwell, T.⁴  Walker, J. P.⁵  Berg, A.⁶  McNairn, H.⁷  Thibeault, M.⁸  Martinez-Fernandez, J.⁹  Jensen, K. H.¹⁰  Asanuma, J.¹¹  Seyfried, M. S.¹²  Bosch, D. D.¹³  Starks, P. J.¹⁴  Collins, C. Holifield¹⁵  Prueger, J. H.¹⁶  Su, Z.¹⁷  Lopez-Baeza, E.¹⁸  Yueh, S. H.¹ 

[1] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA

[2] USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD USA

[3] NASA, Goddard Space Flight Ctr, Greenbelt, MD USA

[4] Univ Texas Austin, Austin, TX 78712 USA

[5] Monash Univ, Clayton, Vic, Australia

[6] Univ Guelph, Guelph, ON, Canada

[7] Agr & Agri Food Canada, Ottawa, ON, Canada

[8] Comis Nacl Actividades Espaciales CONAE, Buenos Aires, DF, Argentina

[9] Univ Salamanca, Inst Hispano Luso Invest Agr CIALE, Salamanca, Spain

[10] Univ Copenhagen, Copenhagen, Denmark

[11] Univ Tsukuba, Tsukuba, Ibaraki, Japan

[12] USDA ARS, Northwest Watershed Management Res, Boise, ID 83712 USA

[13] USDA ARS, Southeast Watershed Res, Tifton, GA 31793 USA

[14] USDA ARS, Grazinglands Res Lab, El Reno, OK USA

[15] USDA ARS, Southwest Watershed Res, Tucson, AZ USA

[16] USDA ARS, Natl Lab Agr & Environm, Ames, IA USA

[17] Univ Twente, Enschede, Netherlands

[18] Univ Valencia, Valencia, Spain

关键词: SMAP;    Soil moisture;    Spatial resolution;    In situ;   

DOI  :  10.1016/j.rse.2018.02.006

来源: Elsevier

【 摘 要 】

Satellite-based passive microwave remote sensing typically involves a scanning antenna that makes measurements at irregularly spaced locations. These locations can change on a day to day basis. Soil moisture products derived from satellite-based passive microwave remote sensing are usually resampled to a fixed Earth grid that facilitates their use in applications. In many cases the grid size is finer than the actual spatial resolution of the observation, and often this difference is not well understood by the user. Here, this issue was examined for the Soil Moisture Active Passive (SMAP) enhanced version of the passive-based soil moisture product, which has a grid size of 9-km and a nominal spatial resolution of 33-km. In situ observations from core validation sites were used to compute comparison metrics. For sites that satisfied the established reliability and scaling criteria, the impact of validating the 9-km grid product with in situ data collected over a 9-km versus a 33-km domain was very small for the sites studied (0.039 m(3)/m(3) unbiased root mean square difference for the 9-km case versus 0.037 m(3)/m(3) for the 33-km case). This result does not mean that the resolution of the product is 9-km but that for the conditions studied here the soil moisture estimated from in situ observations over 9-km is a close approximation of the soil moisture estimated from in situ observations over the 33-km resolution. The implication is that using the enhanced SMAP product at its grid resolution of 9-km should not introduce large errors in most applications.

【 授权许可】

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