title: Assessment of Evapotranspiration and Soil Moisture Content Across Different Scales of Observation.
abstract: The proper assessment of evapotranspiration and soil moisture content arefundamental in food security research, land management, pollution detection, nutrient flows,(wild-) fire detection, (desert) locust, carbon balance as well as hydrological modelling; etc.This paper takes an extensive, though not exhaustive sample of international scientificliterature to discuss different approaches to estimate land surface and ecosystem relatedevapotranspiration and soil moisture content. This review presents:(i) a summary of the generally accepted cohesion theory of plant water uptake andtransport including a shortlist of meteorological and plant factors influencing planttranspiration;(ii) a summary on evapotranspiration assessment at different scales of observation (sapflow,porometer, lysimeter, field and catchment water balance, Bowen ratio,scintillometer, eddy correlation, Penman-Monteith and related approaches);(iii) a summary on data assimilation schemes conceived to estimate evapotranspirationusing optical and thermal remote sensing; and(iv) for soil moisture content, a summary on soil moisture retrieval techniques atdifferent spatial and temporal scales is presented.Concluding remarks on the best available approaches to assess evapotranspiration and soilmoisture content with and emphasis on remote sensing data assimilation, are provided.
authors.affiliation: Geomatics Engineering, Katholieke Universiteit Leuven (K.U.Leuven), Celestijnenlaan 200E, BE-3001 Heverlee, Flanders, Belgium. willem.verstraeten@biw.kuleuven.be.
authors.forename: Willem W
authors.initials: WW
authors.lastname: Verstraeten
authors.affiliation: Centre for Remote Sensing and Earth Observation Processes, Flemish Institute for Technological Research (VITO), Boeretang 200, BE-2400 Mol, Flanders, Belgium. frank.veroustraete@vito.be.
authors.forename: Frank
authors.initials: F
authors.lastname: Veroustraete
authors.affiliation: Division Soil and Water Management, Katholieke Universiteit Leuven (K.U.Leuven), Celestijnenlaan 200E, BE-3001 Heverlee, Flanders, Belgium. jan.feyen@biw.kuleuven.be.
authors.forename: Jan
authors.initials: J
authors.lastname: Feyen
keywords: Evapotranspiration; plant – field – landscape - regional scales; remote sensing; soil moisture content