The National Airborne Field Experiments: Towards 1 km Resolution Soil Moisture
Olivier Merlin, Jeffrey Walker, Rocco Panciera, Jetse Kalma, Ed Kim and Jorg Hacker
The National Airborne Field Experiments (NAFE) are a series of two one month-long campaigns designed for addressing two science questions:
(i) how to downscale passive microwave near-surface soil moisture data ?
(ii) how to derive high resolution root zone soil moisture ?
The first campaign was undertaken during November 2005 (NAFE’05) in the Goulburn River catchment, Australia. The objective of NAFE’05 was to provide high resolution data for process level understanding of soil moisture retrieval, scaling and data assimilation. To meet this objective, the Polarimetric L-band Multibeam Radiometer (PLMR), a thermal imager and a tri-spectral scanner was flown onboard a motor glider at four different altitudes from 625 ft to 10,000 ft AGL, resulting in L-band data at 62.5-m, 250-m, 500-m and 1-km resolution; thermal infrared data at approximately 1.25-m, 5-m, 10-m and 20-m resolution; and visible and near-infrared data at approximately 1-m resolution. Coincident ground data were collected on embedded spatial scales of 6.25 m to 1 km.
The second campaign is scheduled for November 2006 (NAFE’06) in the Murrumbidgee catchment, Australia. The objective of NAFE’06 is to provide data for SMOS (Soil Moisture and Ocean Salinity) level soil moisture retrieval, downscaling and data assimilation. To meet this objective, PLMR and supporting instruments will be flown at an altitude of 10,000 ft AGL to provide 1-km resolution passive microwave data across a km2 area every 2-3 days. This will both simulate SMOS pixels and provide the 1-km soil moisture data required for downscale verification. Moreover, the downscaling and near-surface soil moisture assimilation techniques will be tested with remote sensing data which are consistent with that from current and planned satellite sensors.
In this paper, an overview of the NAFE’05 data set and experiment plan for NAFE’06 is presented.