Journal article
Accuracy of the Temperature-Vegetation Dryness Index using MODIS under water-limited vs. energy-limited evapotranspiration conditions
Department of Environmental Engineering, Technical University of Denmark1
Water Resources Engineering, Department of Environmental Engineering, Technical University of Denmark2
CSIC3
Universidad Pablo de Olavide4
National Space Institute, Technical University of Denmark5
Microwaves and Remote Sensing, National Space Institute, Technical University of Denmark6
Water deficit indices based on the spatial relationship between surface temperature (Ts) and NDVI, known as triangle approaches, are widely used for drought monitoring. However, their application has been recently questioned when the main factor limiting evapotranspiration is energy. Even though water is the main control in dryland ecosystems, these can also undergo periods of energy and temperature limitation.
In this paper we aimed to: (i) evaluate the TVDI (Temperature-Vegetation Dryness Index) to estimate water deficits (e.g. ratio between actual and potential evapotranspiration), and heat surface fluxes using MODIS data; and (ii) provide insights about the factors most affecting the accuracy of results.
Factors considered included the type of climatic control on evapotranspiration, λE, (i.e. water-limited vs. energy-limited), the quality of Tair estimates, the heterogeneity of land cover types and climatic variables in the region, or the algorithm to extract hydrological boundaries from the images.
The TVDI was compared with eddy covariance (EC) data from two shrublands with different climatic controls for λE in South Spain. Evaluations showed that it could be used to estimate the water deficit when water was the main limiting factor (R=0.81-0.88; Mean Average Error, MAE=0.16-0.17) but not in energy-limited situations (R
Language: | English |
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Year: | 2014 |
Pages: | 100-117 |
ISSN: | 18790704 and 00344257 |
Types: | Journal article |
DOI: | 10.1016/j.rse.2014.04.002 |
ORCIDs: | Garcia, Monica and 0000-0002-3814-2536 |
Algorithms Atmospheric temperature Eco-hydrology Ecohydrology Ecosystem control Ecosystem controls Ecosystems Eddy covariance Energy balance Estimation Evapotranspiration Heat flux Interfacial energy Land surface temperature Radiometers SDG 13 - Climate Action SDG 15 - Life on Land Surface energy balance Surface measurement Triangle approach Vegetation Water stress