Growing Season Evapotranspiration with Satellite Remote Sensing Procedure
Abstract
Water is the most important constraint facing agriculture in the most of the Central High Plains of the U.S.A.. Local, state and federal water management regulatory agencies need good quality water use estimates by different land surfaces to assess short and long-term water management, planning, and allocations on a watershed scale. Evapotranspiration (ET) can be defined as the loss of water from the ground, lake or pond, and vegetative surfaces to the atmosphere through vaporization of liquid water. The ability is required to accurately estimate the magnitude of this flux will, therefore, go a long way towards being able to compute the water balance and plan the water resources and regimes.. Furthermore, quantification of this flux on a watershed or a regional scale is much more difficult. In this study we applied the Mapping Evapotranspiration at High Resolution with internal calibration (METRIC) to obtain ET maps for Central and Western parts of Nebraska. Landsat 5 and Landsat 7 images were processed for the 2005 and 2007 growing seasons to obtain instantaneous and daily ET. Monthly and Seasonal ET data are rarely presented in previous studies and are often required for quantifying water consumption. In order to produce monthly and seasonal ET maps, individual daily ET maps generated from METRIC were interpolated between dates on a daily basis using a cubic-spline model. Cloud artifacts were removed and filled back in using interpolated ET data and a daily background evaporation adjustment based on the FAO-56 Ke evaporation model. The maps generated by the METRICtm allowed us to follow the seasonal trend in evaporative faction and ET for major land use classes. If calibrated properly, the model could be a viable tool to estimate water use in managed and native ecosystems in sub-humid climates at a large scale. The METRICtm approach presented in this paper illustrated how an ‘off-the-shelf’ model can be applied operationally over a significant time period and how that model behaves. The findings makes considerable contribution to our understanding of estimating surface energy fluxes using remote sensing approach and experimentally describes the operational characteristics of METRICtm.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.H23J..08I
- Keywords:
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- 1818 HYDROLOGY / Evapotranspiration