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. Author manuscript; available in PMC: 2020 Jul 13.
Published in final edited form as: IEEE Trans Geosci Remote Sens. 2017 Jan 5;55(4):1954–1966. doi: 10.1109/tgrs.2016.2631978

TABLE I.

SMAP Radiometer Science and Instrument Requirements

Scientific Requirements Measurement Instrument Requirements Functional
Soil Moisture: 0.04 m3m−3 volumetric uncertainty (1-σ) in the top 5 cm for vegetation water content ≤ 5 kg m−2; Hydroclimatology at 40-km resolution L-Band Radiometer (1.41 GHz): Polarization: V, H, T3 and T4 Project 3-dB beamwidth ≤ 40 km Radiometric Uncertainty ≤ 1.3 K Constant 40° incidence angle
Sample diurnal cycle at consistent time of day (6am/6pm Equator crossing); Global, 3-day (or better) revisit Swath Width: 1000 km Minimize Faraday rotation
Observation over minimum of three annual cycles Baseline three-year mission life

Observation over minimum of Baseline three-year mission life three annual cycles