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United States Department of Agriculture

Agricultural Research Service

Title: Heat Flux Distributions over Sgp '97 Sites

Authors
item French, Andrew
item Schmugge, Thomas
item Kustas, William

Submitted to: International Geoscience and Remote Sensing Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 1, 2000
Publication Date: July 24, 2000

Interpretive Summary: Spatially distributed surface heat flux surveys at El Reno, Oklahoma, are estimated from the combination of remote sensing data and ground data. The estimates are for various morning and afternoon surveys from June 29 to July 2, 1997. These surveys were made during clear skies and followed a heavy precipitation event (61.4mm). Surface sensible and latent heat fluxes are computed for each remote sensing pixel. By using a "two-source" energy model, these components are partitioned into vegetation and soil contributions. Estimated surface fluxes generally compared well with independently measured fluxes from tower-based observations. Bare soil surfaces show the effects of dry-down by successively diminishing latent heat fluxes from day to day while vegetative latent heat fluxes show little change.

Technical Abstract: Spatial distributions of surface energy fluxes were estimated from remotely sensed data collected during the Southern Great Plains Experiment (SGP97) campaign in Oklahoma. Aircraft data from multi-banded, thermal infrared sensors, and from visible-near infrared sensors were combined with ground and satellite observations to predict sensible and latent heat fluxes from the soil and vegetation surfaces. These energy fluxes were computed using parallel two-source model. The method utilizes surface temperatures and vegetation cover derived from remote sensing data, meteorological data such as surface wind speed, air temperature, and humidity from ground observation data. Energy fluxes were computed from SGP97 sites at El Reno, Oklahoma, at midmorning times on June 29 to July 2, 1997, which correspond to a dry-down period immediately following a 61.4mm rainfall on June 28. When compared with surface-based measurements, modeled evaporative fractions were generally in good agreement. Evaporative fractions over vegetated fields showed small changes while the evaporative fractions markedly decreased over bare soil.

Last Modified: 12/19/2014
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