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Proceedings Paper

Remote sensing techniques to measure dew: the detection of canopy water with an L-band passive microwave radiometer and a spectral reflectance sensor
Author(s): Richard A. M. De Jeu; Bert G. Heusinkveld; Hans Vugts; Thomas R. H. Holmes; Manfred Owe
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Paper Abstract

A technique to quantify the amount of dew on grassland with an L-band (1.4 GHz) passive microwave radiometer has been presented. The horizontal polarized brightness temperature is sensitive to dew and morning dew can increase the temperature up to 5 K. This is in contrary to recent published results, where they expect that dew does not have any effect on L band (1.4 GHz) observations. By using both the horizontal and vertical polarized brightness temperature in combination with measured soil moisture conditions we were able to estimate the amount of dew. The results compared well with another remote sensing technique to measure dew using a spectral reflectance sensor. In addition, a simple comparison study was done to study the sensitivity of the microwave emission on dew events and changes in internal water. This study showed that the microwave emission at L band is more sensitive to changes in dew than to changes in internal vegetation water content when the soil is wet. When the soil is dry, the microwave emission is more sensitive to internal vegetation water.

Paper Details

Date Published: 26 October 2004
PDF: 11 pages
Proc. SPIE 5568, Remote Sensing for Agriculture, Ecosystems, and Hydrology VI, (26 October 2004); doi: 10.1117/12.573929
Show Author Affiliations
Richard A. M. De Jeu, Vrije Univ. Amsterdam (Netherlands)
Bert G. Heusinkveld, Wageningen Univ. (Netherlands)
Hans Vugts, Vrije Univ. Amsterdam (Netherlands)
Thomas R. H. Holmes, NASA Goddard Space Flight Ctr. (United States)
Manfred Owe, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 5568:
Remote Sensing for Agriculture, Ecosystems, and Hydrology VI
Manfred Owe; Guido D'Urso; Ben T. Gouweleeuw; Anne M. Jochum, Editor(s)

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