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Intercomparison of Surface Energy Fluxes Estimates from the FEST-EWB and TSEB Models over the Heterogeneous REFLEX 2012 Site (Barrax, Spain)

Corbari Ch., Timmermans W., Andreu A.

Acta Geophysica

2015

Vol. 63, no. 6

1609--1638

An intercomparison between the Energy Water Balance model (FEST-EWB) and the Two-Source Energy Balance model (TSEB) is performed over a heterogeneous agricultural area. TSEB is a residual model which uses Land Surface Temperature (LST) from remote sensing as a main input parameter so that energy fluxes are computed instantaneously at the time of data acquisition. FEST-EWB is a hydrological model that predicts soil moisture and the surface energy fluxes on a continuous basis. LST is then a modelled variable. Ground and remote sensing data from the Regional Experiments For Land-atmosphere Exchanges (REFLEX) campaign in 2012 in Barrax gave the opportunity to validate and compare spatially distributed energy fluxes. The output of both models matches the ground observations quite well. However, a spatial analysis reveals significant differences between the two approaches for latent and sensible heat fluxes over relatively small fields characterized by high heterogeneity in vegetation cover.

An Overview of the Regional Experiments for Land-Atmosphere Exchanges 2012 (Reflex 2012) Campaign

Timmermans W. J., Tol Ch. van der, Timmermans J., Ucer M., Chen X., Alonso L., Moreno J., Carrara A., Lopez R., Cruz Tercero F. de la, Corcoles H. L., Miguel E. de, Sanchez J. A. G., Pérez I., Franch B., Munoz J.-C. J., Skokovic D., Sobrino J., Soria G., MacArthur A., Vescovo L., Reusen I., Andreu A., Burkart A., Cilia Ch., Contreras S., Corbari Ch., Calleja J. F., Guzinski R., Hellmann Ch., Herrmann I., Kerr G., Lazar A.-L., Leutner B., Mendiguren G., Nasilowska S., Nieto H., Pachego-Labrador J., Pulanekar S., Raj R., Schikling A., Siegmann B., Bueren S. von, Su Z.

Acta Geophysica

2015

Vol. 63, no. 6

1465--1484

The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites.

An Analysis of Turbulent Heat Fluxes and the Energy Balance During the REFLEX Campaign

Tol Ch. van der, Timmermans W., Corbari Ch., Carrara A., Timmermans J., Su Z.

Acta Geophysica

2015

Vol. 63, no. 6

1516--1539

Three eddy covariance stations were installed at the Barrax experimental farm during the Land-Atmosphere Exchanges (REFLEX) airborne training and measurement campaign to provide ground truth data of energy balance fluxes and vertical temperature and wind profiles. The energy balance closure ratio (EBR) was 105% for a homogeneous camelina site, 86% at a sparse reforestation site, and 73% for a vineyard. We hypothesize that the lower closure in the last site was related to the limited fetch. Incorporating a vertical gradient of soil thermal properties decreased the RMSE of the energy balance at the camelina site by 16 W m-2. At the camelina site, eddy covariance estimates of sensible and latent heat fluxes could be reproduced well using mean vertical profiles of wind and temperature, provided that the Monin-Obukhov length is known. Measured surface temperature and sensible heat fluxes suggested high excess resistance for heat (kB-1 = 17).