In arid and semi-arid environments, the characterization of the inter-annual variations of the light use efficiency ε due to water stress still relies mostly on meteorological data. Thus the GPP estimation based on procedures exclusively driven by remote sensing data has not found yet a widespread use. In this work, the potential to characterize the water stress in semi-natural vegetation of three spectral indices (NDWI, SIWSI and NDI7) – from MODIS broad spectral bands – has been analyzed in comparison to a meteorological factor (Cws). The study comprises 70 sites (belonging to 7 different ecosystems) uniformly distributed over Tuscany, and three eddy covariance tower sites. An operational methodology, which combines meteorological and MODIS data, to characterize the inter-annual variations of ε due to summer water stress is proposed. Its main advantage is that it relies on existing series of meteorological data characterizing each site and allows calculating a typical Cws profile that can be “updated” (C∗ ws) for the actual conditions using MODIS spectral indices. The results confirm that the modified C∗ ws can be used as a proxy of water stress that does not require concurrent information on meteorological data.

MORENO A.;  MASELLI Fabio;  CHIESI M.;  GENESIO Lorenzo;  VACCARI Francesco;  SEUFERT Guenther;  GILABERT Maria Amparo; 

2014-02-26

ELSEVIER SCIENCE BV

JRC87575

0303-2434,   

http://www.sciencedirect.com/science/article/pii/S0303243413000895,    https://publications.jrc.ec.europa.eu/repository/handle/JRC87575,   

10.1016/j.jag.2013.08.003,