Soil Moisture Active Passive Validation Experiment 2008

The Soil Moisture Active Passive Mission (SMAP) is currently in Phase A and addressing numerous issues related to the L3 soil moisture retrieval algorithms. During discussions at the SMAP Workshop in June 2007, at pre-Phase A Science Transition Team meetings, and previously during Soil Moisture Mission Working Group meetings, a number of specific questions have been identified. Many of these questions need to be answered in the near-term:

•          How well do new alternative RFI suppression techniques under consideration for SMAP work over RFI contaminated land areas? (RFI)

•          There is a lack of robust sets of concurrent passive and active L-band observational data including temporal change for algorithm development and validation. Concurrent active-passive is what is new with SMAP and we have very few data sets to date for algorithm development and evaluation. (TAP)

•          How do high resolution SAR relate to lower resolution radar data of SMAP? There are potentially valuable SAR resources (PALSAR and UAVSAR) that can contribute to SMAP validation. (RS)

•          What effect does azimuthal orientation have on radar backscatter for different land covers and topographic conditions at the spatial resolution of SMAP? This is a significant question in using temporal change algorithms. (AZ)

•          Does topography have to be accounted for in retrievals? (TOPO)

•          Can soil moisture be retrieved over urbanized areas? (URBAN)

•          Under what conditions can we expect to retrieve soil moisture under forest canopies? (FOREST)

Addressing these issues as soon as possible would contribute to mission definition and algorithms design and selection.  To the necessary information, a series of aircraft-based flights will be conducted on the Eastern Shore of Maryland and Delaware in the fall of 2008 (~two weeks in early October). The primary sensor for this campaign will be the Passive Active L-Band System (PALS); however, several other new instruments will be part of the experiment. This will be the first SMAP Validation Experiment (SMAPVEX08).

The Experiment Plan