Details

Autor(en) / Beteiligte

• Reichle, Rolf H.
• De Lannoy, Gabrielle J. M.
• Liu, Qing
• Ardizzone, Joseph V.
• Colliander, Andreas
• Conaty, Austin
• Crow, Wade
• Jackson, Thomas J.
• Jones, Lucas A.
• Kimball, John S.
• Koster, Randal D.
• Mahanama, Sarith P.
• Smith, Edmond B.
• Berg, Aaron
• Bircher, Simone
• Bosch, David
• Caldwell, Todd G.
• Cosh, Michael
• González-Zamora, Ángel
• Collins, Chandra D. Holifield
• Jensen, Karsten H.
• Livingston, Stan
• Lopez-Baeza, Ernesto
• Martínez-Fernández, José
• McNairn, Heather
• Moghaddam, Mahta
• Pacheco, Anna
• Pellarin, Thierry
• Prueger, John
• Rowlandson, Tracy
• Seyfried, Mark
• Starks, Patrick
• Su, Zhongbo
• Thibeault, Marc
• Van Der Velde, Rogier
• Walker, Jeffrey
• Wu, Xiaoling
• Zeng, Yijian

Titel

Assessment of the SMAP Level-4 Surface and Root-Zone Soil Moisture Product Using In Situ Measurements

Ist Teil von

• Journal of hydrometeorology, 2017-10, Vol.18 (10), p.2621-2645

Ort / Verlag

American Meteorological Society

Erscheinungsjahr

2017

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The Soil Moisture Active Passive (SMAP) mission Level-4 Surface and Root-Zone Soil Moisture (L4_SM) data product is generated by assimilating SMAP L-band brightness temperature observations into the NASA Catchment land surface model. The L4_SM product is available from 31 March 2015 to present (within 3 days from real time) and provides 3-hourly, global, 9-km resolution estimates of surface (0–5 cm) and root-zone (0–100 cm) soil moisture and land surface conditions. This study presents an overview of the L4_SM algorithm, validation approach, and product assessment versus in situ measurements. Core validation sites provide spatially averaged surface (root zone) soil moisture measurements for 43 (17) “reference pixels” at 9- and 36-km gridcell scales located in 17 (7) distinct watersheds. Sparse networks provide point-scale measurements of surface (root zone) soil moisture at 406 (311) locations. Core validation site results indicate that the L4_SM product meets its soil moisture accuracy requirement, specified as an unbiased RMSE (ubRMSE, or standard deviation of the error) of 0.04 m³ m−3 or better. The ubRMSE for L4_SM surface (root zone) soil moisture is 0.038 m³ m−3 (0.030 m³ m−3) at the 9-km scale and 0.035 m³ m−3 (0.026 m³ m−3) at the 36-km scale. The L4_SM estimates improve (significantly at the 5% level for surface soil moisture) over model-only estimates, which do not benefit from the assimilation of SMAP brightness temperature observations and have a 9-km surface (root zone) ubRMSE of 0.042 m³ m−3 (0.032 m³ m−3). Time series correlations exhibit similar relative performance. The sparse network results corroborate these findings over a greater variety of climate and land cover conditions.