Submitted to: Agronomie Agriculture Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 4, 1999
Publication Date: October 15, 1999
Interpretive Summary: The purpose of this paper is to provide a review of the current status of thermal infrared remote sensing for agricultural application in a relatively new journal. The basic physics of thermal infrared remote sensing is presented along with examples of results.
Measurements of thermal radiation of infrared wavelengths (7 to 14 micrometers) yield much information about the land surface. The primary use of these observations is for surface temperature determination as the emissivity is usually close to one. For this purpose it is fortuitous that the peak in the thermal emission occurs in an atmospheric transmission window. In addition, there are variations in the emissivity of minerals and soils in the 7 to 14 micrometers region which can be interpreted for identification purposes. The emissivity for vegetative canopies has been found to be close to one with little spectral variation. Applications of the derived surface temperature to study the surface energy balance and to estimate the energy fluxes from the land surface are discussed. The basic concepts of the energy balance at the land surface are presented along with and example of how remotely sensed surface brightness temperatures can be used to estimate the sensible heat and to estimate plant water use. The example is from the Monsoon 90 experiment conducted over an arid watershed in the state of Arizona in the United States. In this case, surface temperatures derived from an aircraft thermal infrared sensor and vegetation and lad use characteristics derived from a Landsat TM image were used in a two source model to predict the surface heat fluxes. The agreement with ground measurements is reasonably good for the three days of observation.