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ASCAT Soil Moisture NOAA NESDIS SMCD EMB. The Advanced SCATerometer (ASCAT). Is a real aperture radar using fan-beam geometry. Operates at 5.225GHz (C-band) MW, VV-pol. Swath gridded into nodes, one 0 triplet per node. Retrieve for primarily sea wind (speed & direction).
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The Advanced SCATerometer (ASCAT) • Is a real aperture radar using fan-beam geometry. • Operates at 5.225GHz (C-band) MW, VV-pol. • Swath gridded into nodes, one 0 triplet per node. • Retrieve for primarily sea wind (speed & direction). • Also surface type, veg cover, and soil moisture. • Global 25x25km2 coverage, ave 4-20 0 triplets/day. • Day/night and all weather operation. • Heritage from ERS-1/ERS-2 (1991-) scatterometers.
ASCAT One Day Coverage • 29 day orbit repeat; • Daily global 25x25 km2 grids; • Average # of 0triplets varies lat.; • ~4-20 0triplets per day;
ASCAT Soil Moisture Retrievals • Example soil moisture data from ERS scatterometer for two different years; • Dramatic differences in soil moisture across Europe in January; • Dramatic changes between two different years.
AMSR-E USDA SM Validation Sites Little River, GA Reynolds Creek, ID Walnut Gulch, AZ Little Washita, OK
AMSR-E U.S. Soil Moisture Validation Rmse = 6% R = 0.46
ASCAT Soil Moisture Assessment Plan 1. Extract ASCAT soil moisture retrievals2. Compare with AMSR-E soil moisture retrievals3. Compare with ground network SM observations4. Collaborate with TUW for potential improvements