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Title: Global canopy interception from satellite observations

Author
item Miralles, D - Vrije University
item Gash, J - Vrije University
item Holmes, Thomas
item De Jeu, R - Vrije University
item Dolman, H - Vrije University

Submitted to: Journal of Geophysical Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2010
Publication Date: 8/31/2010
Citation: Miralles, D., Gash, J., Holmes, T.R., De Jeu, R., Dolman, H. 2010. Global canopy interception from satellite observations. Journal of Geophysical Research. 115:D16122.

Interpretive Summary: Water lost to the atmosphere through evaporation is an important component of the global hydrological cycle, and knowledge of the magnitude of this flux is crucial for an accurate prediction that future effects of climate change may have on patterns of precipitation and drought. The total evaporation flux can be separated into three different pathways: evaporation directly from the soil, transpiration of the plants, and evaporation of intercepted water on tall canopies. In forests this last component can account for a fifth of the total evaporation flux. This article describes a global implementation of a method that was originally developed to model the evaporation of intercepted water as measured at field sites.

Technical Abstract: A new methodology for retrieving rainfall interception rates from multi satellite observations is presented. The approach makes use of the daily productof the Global Precipitation Climatology Project (GPCP) as driving data and applies Gash’s analytical model to derive interception rates at global scale. Results compare well with field observations of rainfall interception (R=0.76, n=38). Global estimates are presented and spatial differences in the distribution of interception over different ecosystems analyzed. According to our findings, interception loss is responsible for the evaporation of approximately 14% of the total incoming rainfall over broadleaf evergreen forests, 17% in broadleaf deciduous and 23% in needleleaf forests. The product is sensitive to rainfall intensity and forest cover, offering the potential to study the impact of climate change and deforestation on the dynamics of the global hydrological cycle.