2002 Annual

Monday, 14 January 2002
Remote Estimates of Surface Energy Fluxes on the 30-m Spatial Scale
John R. Mecikalski, CIMSS/Univ. of Wisconsin, Madison, WI; and R. D. Torn, J. M. Norman, M. C. Anderson, S. J. Richardson, and J. A. Brotzge
Continental-scale maps of real-time daily surface energy fluxes are being generated using the Atmospheric Land-Exchange Inverse (ALEXI) model at the University of Wisconsin. This model uses GOES-derived surface brightness temperature changes, AVHRR-derived land cover properties, vegetation-type maps and synoptic weather data. Sensible, latent and ground heat flux components along with net radiation are calculated on a 5-km grid from these inputs. A collaboration between the University of Wisconsin and the University of Oklahoma is focusing on the validation of these ALEXI flux estimates by comparing them to in-situ fluxes obtained from the 114 station Oklahoma Mesonet. Using LandSat-7 thermal data along with Landsat vegetation-index estimates, we are able to disaggregate these ALEXI fluxes to 30 meter resolution to get a better estimate of the true station surface fluxes using the model. Plots of surface fluxes over a 5 km ALEXI box are very heterogeneous, yet the average of these 30 m fluxes is consistent with the ALEXI 5 km flux even though they are not constrained to sum up to the ALEXI fluxes. The 30 meter scale fluxes compare more favorably to the mesonet station fluxes then the 5 km scale fluxes.

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