Texas A&M takes lead on tropical forest evapotranspiration grant awarded by DOE

Writer: Kay Ledbetter, 806-677-5608, skledbetter@ag.tamu.edu
Contact: Dr. Georgianne Moore, 979-845-3765, gwmoore@tamu.edu

COLLEGE STATION – Dr. Georgianne Moore, associate professor in the Texas A&M University department of ecosystem science and management, will be part of a team studying the flux of water vapor and carbon dioxide within tropical forests.

The Department of Energy awarded the team a $774,000 grant for research at the Texas A&M Soltis Center for Research and Education in Costa Rica entitled: Improving Land-Surface Modeling of Evapotranspiration Processes in Tropical Forests.

The project’s principal investigator is Dr. Gretchen Miller, assistant professor in the Texas A&M department of civil engineering. In addition to Moore, the other co-investigators are Dr. Anthony Cahill, associate professor in the Texas A&M department of civil engineering, and Dr. Ruby Leung, Laboratory Fellow at the DOE Pacific Northwest National Laboratory in Richland, Wash.

The project’s principal investigator is Dr. Gretchen Miller, assistant professor in the Texas A&M department of civil engineering. In addition to Moore, the other co-investigators are Dr. Anthony Cahill, associate professor in the Texas A&M department of civil engineering, and Dr. Ruby Leung, Laboratory Fellow at the DOE Pacific Northwest National Laboratory in Richland, Wash.

The overall goal of this project is to improve the modeling of fluxes of water vapor and carbon dioxide to and from tropical forests with a particular focus on transitions between wet and dry canopy conditions, Moore said.

This goal will be achieved through a combined program of field-based measurements in a mountainous tropical forest in Costa Rica and regional scale modeling of land surface fluxes in the Neotropic ecozone of South America, Central America and the Caribbean.

Specifically, the project will collect targeted hydrological and meteorological measurements along in-canopy and above-canopy profiles at locations throughout a mountainous forest watershed at the Texas A&M Soltis Center, Miller said.

Moore said she will primarily be doing fieldwork; taking measurements at the field site in Costa Rica of evapotranspiration and partitioning that within the canopy. She said they will be hiring two doctoral students to help with the measuring.

In addition, the team will develop a new conceptual framework for modeling wet canopy processes based on the new dataset; revise the Community Land Model or CLM to improve its estimates of evapotranspiration in tropical forests; and model tropical forests and their interactions with rainfall using the improved CLM coupled with the Weather Research and Forecasting model capable of resolving processes in mountainous forests.

Land surface models are used to represent terrestrial processes – evaporation, plant water use and photosynthesis – that shape global climate, Miller said.

While much progress has been made to improve and refine these models, some hydrological processes are not well captured, which hinders the ability to understand land-atmosphere interactions and ultimately to predict impacts of climate change on water resources, she said.

The inadequate representation of evapotranspiration may partly explain why global climate models do not match observed precipitation patterns, the researchers said.

Multiple factors contribute to this problem, they said. In moist tropical regions, high humidity, leaf wetness and cloud cover combine to suppress forest water use and possibly reduce forest growth in ways that are poorly understood. Mountainous areas pose additional difficulties, as standard modeling and measurement techniques are not readily applied in rough terrain.

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