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Proceedings Paper

Error analysis of scaling evapotranspiration over heterogeneous land surface
Author(s): Yuanbo Liu; Tetsuya Hiyama; Yasushi Yamaguchi
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Paper Abstract

Evapotranspiration (ET) is an important component of hydrological cycle and large-scale ET is of great concern in numerous studies of global environmental change. The large-scale ET can be estimated using remotely sensed data and the energy balance based approach, in which the homogeneous land surface is assumed. The difficulty in application of the approach with the homogeneity assumption to the heterogeneous land surface can be released by spatial scaling approach. On the other hand, measurement error always exists even over the homogeneous surfaces, and the error unavoidably propagates into the scaled ET. However, error propagation in scaling received rare attention. To this issue, this paper describes the energy balance based approach and the physics-based scaling functions for expanding the application to heterogeneous surface. Surfaces at a fine-scale are assumed to be homogeneous enough so as to represent a heterogeneous surface at a coarse-scale. From error analysis, a general form of error propagation in ET is derived and then applied to ET at the two scales. Multi-scale analysis results suggest that error in ET estimate, introduced by measurement errors in the relevant variables at the fine-scale, would decline rather than be enhanced, when the variables are scaled up into the coarse-scale using the scaling functions. Therefore, the coarse-scale value would be more accurate with the proper scaling approach adopted.

Paper Details

Date Published: 17 October 2006
PDF: 8 pages
Proc. SPIE 6359, Remote Sensing for Agriculture, Ecosystems, and Hydrology VIII, 635916 (17 October 2006); doi: 10.1117/12.687295
Show Author Affiliations
Yuanbo Liu, Nagoya Univ. (Japan)
Tetsuya Hiyama, Nagoya Univ. (Japan)
Yasushi Yamaguchi, Nagoya Univ. (Japan)

Published in SPIE Proceedings Vol. 6359:
Remote Sensing for Agriculture, Ecosystems, and Hydrology VIII
Manfred Owe; Guido D'Urso; Christopher M. U. Neale; Ben T. Gouweleeuw, Editor(s)

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