Remote Sensing applied to the modelling of evapotranspiration in tropical biomes
Start: 2007
Conclusion: 2011
Nature: Research
Financing: CNPq
Researcher: Anderson Ruhoff
Advisor: Walter Collischonn
Abstract:
Evapotranspiration (ET) plays an important role in the global climate dynamics and in the processes of primary production of terrestrial ecosystems, since it is directly linked to mass transfer and energy balance. The aim of this doctoral thesis was to evaluate the accuracy of ET estimates based on remote sensing models when compared to measurements obtained from flux towers and hydrological models. Two algorithms were selected: for local and regional scales SEBAL was used, while for continental and global scales, MOD16 was adopted. Regarding SEBAL algorithm, the applied methodology showed that significant results were achieved in both latent heat flux and water balance over large areas. Concerning MOD16 algorithm, the research suggested that evapotranspiration estimates showed better results in the long-term and in large areas. The analysis suggests that MOD16 and SEBAL algorithms can capture reasonably well the responses of vegetation in relation to spatial and temporal variability on a large scale. Taking into consideration that these algorithms can be applied from regional to global scales, the results are in an acceptable range of accuracy, indicating a significant potential for monitoring evapotranspiration spatially and temporally, continually and systematically, based on information obtained through the use of remote sensing data.
Keywords:
Amazon, Cerrado Biome, Evapotranspiration, Energy Fluxes, MOD16, MODIS, SEBAL, Remote Sensing.
Publications:
The results of this research were published in the following papers:
RUHOFF, A. L.; PAZ, A. R.; ARAGAO, L. E.O.C.; COLLISCHONN, W.; MU, Q.; MALHI, Y. S.; ROCHA, H. R. Assessment of the MODIS global evapotranspiration algorithm using eddy covariance measurements and hydrological modelling in the Rio Grande basin. Hydrological Sciences Journal, 2013. (Accepted for publication).
RUHOFF, A. L. ; PAZ, A. R. ; COLLISCHONN, W.; ARAGAO, L. E.O.C.; ROCHA, H. R.; MALHI, Y. S. A MODIS-Based Energy Balance to Estimate Evapotranspiration for Clear-Sky Days in Brazilian Tropical Savannas. Remote Sensing, v. 4, p. 703-725, 2012.
RUHOFF, A. L.; PAZ, A. R.; ARAGAO, L. E.O.C.; COLLISCHONN, W.; MU, Q.; MALHI, Y. S.; ROCHA, H. R. Assessing evapotranspiration estimates from the MOD16 Project in the Amazon tropical rainforest. Remote Sensing of the Environment, 2013. (Submitted).
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The complete version of this document is available at http://www.lume.ufrgs.br/handle/10183/32468 (in portuguese).