Evapotranspiration modelling at large scale using near-real time MSG SEVIRI derived data

Abstract

Abstract. We present an evapotranspiration (ET) model developed in the framework of the EUMETSAT "Satellite Application Facility" (SAF) on Land Surface Analysis (LSA). The model is a simplified Soil-VegetationAtmosphere Transfer (SVAT) scheme that uses as input a combination of remote sensed data and atmospheric model outputs. The inputs based on remote sensing are LSA-SAF products: the Albedo (AL), the Downwelling Surface Shortwave Flux (DSSF) and the Downwelling Surface Longwave Flux (DSLF). They are available with the spatial resolution of the MSG SEVIRI instrument. ET maps covering the whole MSG field of view are produced from the model every 30 min, in near-real-time, for all weather conditions. This paper presents the adopted methodology and a set of validation results. The model quality is evaluated in two ways. First, ET results are compared with ground observations (from CarboEurope and national weather services), for different land cover types, over a full vegetation cycle in the Northern Hemisphere in 2007. This validation shows that the model is able to reproduce the observed ET temporal evolution from the diurnal to annual time scales for the temperate climate zones: the mean bias is less than 0.02 mm h −1 and the root-mean square error is between 0.06 and 0.10 mm h −1 . Then, ET model outputs are compared with those from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Global Land Data Assimilation System (GLDAS). From this comparison, a high spatial correlation is noted, between 80 to 90%, around midday. Nevertheless, some discrepancies are also observed and are due to the different input variables and parameterisations used.

State of the Climate in 2016

“…Thus, the weighted use of multiple retrieval approaches is usually advised (Miralles et al 2016;McCabe et al 2016). While the operational monitoring of continental evaporation is becoming a realistic proposition (Ghilain et al 2011;Anderson et al 2011), current algorithms dedicated to estimating evaporation from satellite observations at global scales are mostly intended for research applications and are not currently updated in near-real time.…”

Realization of daily evapotranspiration in arid ecosystems based on remote sensing techniques

“…Nevertheless, conventional methods of evapotranspiration estimations are incapable of fulfilling the quest for regional evapotranspiration estimation, specifically in harsh climatic conditions (Gavilán et al, 2006;Ghilain et al, 2011). Therefore, remote sensing evapotranspiration models are adequate techniques for obtaining satisfactory estimates (Allen et al, 2007a, b;De Bruin et al, 2010).…”

“…Based on several scholarly works by Roerink et al (2000), Su (2002), Crago and Crowley (2005), Chávez et al (2005), Loheide and Gorelick (2005), Allen et al (2007a, b), Ghilain et al (2011), Psilovikos and Elhag (2013) on remote sensing evapotranspiration-based algorithms, there are principally two types of evapotranspiration estimation concepts on terrestrial surfaces.…”

Satellite products of incoming solar and longwave radiations used for snowpack modelling in mountainous terrain

“…LSA SAF irradiance products were proved to be valuable in plains (e.g. Geiger et al, 2008b;Ineichen et al, 2009;Trigo et al, 2010;Carrer et al, 70 2012; Moreno et al, 2013;Cristóbal and Anderson, 2013), with a significant positive impact when used for soil simulations (Carrer et al, 2012) or evapotranspiration modelling (Ghilain et al, 2011;Sun et al, 2011).…”