Wyniki wyszukiwania - BazTech

Ograniczanie wyników

3 Acta Geophysica

3 2015

Powiadomienia systemowe

Sesja wygasła!
Sesja wygasła!

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Utility of an Automated Thermal-Based Approach for Monitoring Evapotranspiration

Timmermans W. J., Kustas W. P., Andreu A.

Acta Geophysica

2015

Vol. 63, no. 6

1571--1608

A very simple remote sensing-based model for water use monitoring is presented. The model acronym DATTUTDUT (Deriving Atmosphere Turbulent Transport Useful To Dummies Using Temperature) is a Dutch word which loosely translates as “it’s unbelievable that it works”. DATTUTDUT is fully automated and only requires a surface temperature map, making it simple to use and providing a rapid estimate of spatially- distributed fluxes. The algorithm is first tested over a range of environmental and land-cover conditions using data from four short-term field experiments and then evaluated over a growing season in an agricultural region. Flux model output is in satisfactory agreement with observations and established remote sensing-based models, except under dry and partial canopy cover conditions. This suggests that DATTUTDUT has utility in identifying relative water use and as an operational tool providing initial estimates of ET anomalies in data-poor regions that would be confirmed using more robust modeling techniques

Influence of Component Temperature Derivation from Dual Angle Thermal Infrared Observations on TSEB Flux Estimates Over an Irrigated Vineyard

Andreu A., Timmermans W. J., Skokovic D., Gonzalez-Dugo M. P.

Acta Geophysica

2015

Vol. 63, no. 6

1540--1570

A two-source model for deriving surface energy fluxes and their soil and canopy components was evaluated using multi-angle airborne observations. In the original formulation (TSEB1), a single temperature observation, Priestley-Taylor parameterization and the vegetation fraction are used to derive the component fluxes. When temperature observations are made from different angles, soil and canopy temperatures can be extracted directly. Two dual angle model versions are compared versus TSEB1: one incorporating the Priestley-Taylor parameterization (TSEB2I) and one using the component temperatures directly (TSEB2D), for which data from airborne campaigns over an agricultural area in Spain are used. Validation of TSEB1 versus ground measurements showed RMSD values of 28 and 10 Wm-2 for sensible and latent heat fluxes, respectively. Reasonable agreement between TSEB1 and TSEB2I was found, but a rather low correlation between TSEB1 and TSEB2D was observed. The TSEB2D estimates appear to be more realistic under the given conditions.

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.