HR: 0800h
AN: H31A-0134    [Abstracts]
TI: Estimates of total downwelling surface radiation using a high-resolution GOES-based cloud product along with MODIS and AIRS products
AU: * Forman, B A
EM: bforman@ucla.edu
AF: University of California at Los Angeles, 5732D Boelter Hall, Los Angeles, CA 90095-1593, United States
AU: Margulis, S A
EM: margulis@seas.ucla.edu
AF: University of California at Los Angeles, 5732D Boelter Hall, Los Angeles, CA 90095-1593, United States
AB: Total downwelling radiation, along with precipitation, is the primary forcing of land surface processes. Clouds are a first-order modulator in radiation processes as they attenuate solar insolation while simultaneously emitting longwave radiation and therefore are key to capturing the space-time variability in downwelling surface radiation. In this study, a cloud-coupled solar insolation and longwave radiation model is developed using readily available satellite-based measurements of land surface and atmospheric states. The downwelling radiation model uses inputs from the Moderate Resolution Spectroradiometer (MODIS) and Atmospheric Infrared Sounder (AIRS) sensors while cloud coupling is achieved via use of the NASA Visible Infrared Solar-Infrared Split Window Technique (VISST) cloud product. Use of the 4-km VISST product effectively downscales larger scale satellite- derived products (e.g. from AIRS) while at the same time provides finer-scale temporal estimates of atmospheric conditions (i.e., every 30 minutes instead of twice daily and four times daily for AIRS and MODIS measurements, respectively). Temporal gaps in AIRS and MODIS products are further refined by scaling a diurnal climatology look-up table derived from ground-based measurements collected by the Oklahoma Mesonet (OKMESONET) for both clear-sky and cloudy-sky conditions. Error characterization studies comparing satellite-derived estimates of surface states/fluxes against ground-based measurements from the Atmospheric Radiation Measurement Program (ARM) and OKMESONET have been conducted. Analysis of the results focuses on identifying key errors and uncertainties that can be accounted for using an ensemble approach for eventual use in a data assimilation framework. The resulting coupled downwelling radiation model provides estimates at high resolution (4-km spatial resolution at 30 minute intervals) and results from an application in the Southern Great Plains (SGP) region of the United States are presented.
DE: 1847 Modeling
DE: 1855 Remote sensing (1640)
DE: 1878 Water/energy interactions (0495)
DE: 3359 Radiative processes
SC: Hydrology [H]
MN: 2007 Fall Meeting