HR: 1340h
AN: H13C-0440    [Abstracts]
TI: Assessing Remotely Sensed Based Estimates of Evapotranspiration Using a Global Set of Evaluation Datasets.
AU: * Su, H
EM: hongbosu@princeton.edu
AU: McCabe, M F
EM: mmccabe@princeton.edu
AU: Wood, E F
EM: efwood@princeton.edu
AB: Developing a globally robust algorithm for the prediction of surface heat fluxes is a significant challenge. Difficulties in capturing the hydro-climatic variability inherent at global scales have limited the extensive application of remote sensing approaches for characterizing surface heat flux behavior. An increased ability to capture the land surface variability has arisen with the development of a number of key remote sensing based products. Spatial and temporal fields of the surface temperature, land surface cover and vegetation distribution are globally available, offering increased ability to monitor hydrological patterns. Coupled with improved data availability is the growing availability of high quality, in-situ validation datasets, essential for the robust evaluation of model responses. Two such data sets are the WCRP/GEWEX/CEOP reference tower data and the FLUXNET tower data. The Coordinated Enhanced Observing Period (CEOP) activity is an element of the World Climate Research Program (WCRP), initiated by the Global Energy and Water Cycle Experiment (GEWEX). Along with FLUXNET, a global network of carbon dioxide and micro-meteorological tower sites, these programs provide measurements of water vapor and energy exchanges over diverse environments across the globe. Combined, the two datasets form a unique hydro-climatological database with global consistency over a range of climatic and vegetation conditions, making them ideally suited to robustly evaluate regional and meso-scale hydrological models and applications. In this study, observations from CEOP and FLUXNET are used to assess estimates of the evapotranspiration, determined using a number of approaches. The purpose of this analysis is to evaluate the adaptability of varied techniques to different climatic conditions and land cover types and conditions. Forcing data from validation tower sites and widely available remote sensing products are used to produce estimates of the land surface fluxes. Daily and 10-day averaged surface fluxes are computed and compared to in-situ observations. Monthly mean diurnal fluxes are also determined to assess the level of temporal variability throughout the observation period at each of the investigation sites. Comparisons show that model predictions of the energy fluxes indicate some promise towards the development of a robust algorithm to derive a global land surface evapotranspiration product.
DE: 1818 Evapotranspiration
DE: 1833 Hydroclimatology
DE: 1878 Water/energy interactions
DE: 1640 Remote sensing
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting