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Title: A multi-sensor approach to retrieving high resolution daily evapotranspiration maps

Author
item Cammalleri, Carmelo
item Anderson, Martha
item Gao, Feng
item Schull, Mitchell
item HOUBORG, RASMUS - Collaborator
item Kustas, William - Bill

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/9/2012
Publication Date: 5/16/2012
Citation: Cammalleri, C.N., Anderson, M.C., Gao, F.N., Schull, M.A., Houborg, R., Kustas, W.P. 2012. A multi-sensor approach to retrieving high resolution daily evapotranspiration maps [abstract]. Hyperspectral Infrared Imager Symposium, May 16-17, 2012, NASA Goddard Space Flight Center, Greenbelt, MD.

Interpretive Summary:

Technical Abstract: The use of residual surface energy balance approaches to determine spatially distributed evapotranspiration (ET) over large areas has been considered an effective solution in the last years, especially due to the increasing availability of remotely-observed land-surface temperature (LST) data. However, the current generation of satellite missions does not include sensor characterized by both high spatial resolution (< 100 m) and high repeatability (daily). The new generation of sensors, as the ones on board of HyspIRI mission, certainly improves the availability of high frequency data, but cloud coverage and possible malfunctioning practically limit the actual temporal frequency of land-surface temperature retrieval. In this context, the integration of data provided by different sensors seems the only suitable alternative to address this problem. In this case study, the use of a multi-scale, multi-sensor approach is analyzed in which the coarse resolution geostationar data (10-km) are used to map ET at the U.S. continental scale via the Atmosphere-Land Exchange Inverse (ALEXI) model, while the Dis-ALEXI procedure disaggregates ALEXI ET to finer spatial scales using MODIS 1-km (daily) and Landsat 30-m (16 day) sharpened LST imagery. These latter estimates are fused in order to retrieve daily 30-m ET maps. A comparison between the estimates obtained by temporally interpolating the Landsat data in isolation and maps derived by the fusion approach allows us to quantify the value added in the introduction of coarse resolution/high frequency estimates in the modeling framework, especially when the theoretical frequency is limited by practical reasons. Moreover, this approach, designed to use the Landsat data is suitable for exploiting HyspIRI mission potentialities after launch.