Diurnal Emissivity Dynamics in Bare vs. Biocrusted Sand Dunes

PDF

Authors
  1. Rozenstein, O.
  2. Agam, N.
  3. Serio, C.
  4. Masiello, G.
  5. Venafra, S.
  6. Achal, S.
  7. Puckrin, E.
  8. Karnieli, A.
Corporate Authors
Defence Research and Development Canada, Valcartier Research Centre, Quebec QC (CAN);Ben-Gurion Univ of the Negev, Sede (ISRAEL);Basilicata Univ, Potenza (ITALY);ITRES Research Ltd, Calgary ALTA (CAN)
Abstract
Estimation of land surface emissivity (LSE) by remote sensing in the thermal infrared is mainly dependent on the ground cover and changes in soil moisture. The LSE is a critical variable that affects the prediction accuracy of geophysical models requiring land surface temperature as an input, highlighting the need for an accurate derivation of LSE. The primary aim of this study was to test the hypothesis that diurnal changes in emissivity, as detected from space, are larger for areas mostly covered by biocrusts (composed mainly of cyanobacteria) than for bare sand areas. The LSE dynamics were monitored from geostationary orbit by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over a sand dune field in a coastal desert region extending across both sides of the Israel-Egypt political borderline. Different land-use practices by the two countries have resulted in exposed, active sand dunes on the Egyptian side (Sinai), and dunes stabilized by biocrusts on the Israeli side (Negev). Since biocrusts adsorb more moisture from the atmosphere than bare sand does, and LSE is affected by the soil moisture, diurnal fluctuations in LSE were larger for the crusted dunes in the 8.7 µm channel. This phenomenon is attributed to water vapor adsorption by the sand/biocrust particles. The results indicate that LSE is sensitive to minor changes in soil water content caused by water vapor adsorption and can, therefore, serve as a tool for quantifying this effect, which has a large spat
Keywords
thermal remote sensing;LWIR;biocrust;sand dunes;water vapor absorption
Report Number
DRDC-RDDC-2014-P102 — External Literature
Date of publication
05 Mar 2015
Number of Pages
24
DSTKIM No
CA040019
CANDIS No
801005
Format(s):
Electronic Document(PDF)

Permanent link

Document 1 of 1

Date modified: