Skip to main content
ARS Home » Pacific West Area » Tucson, Arizona » SWRC » Research » Research Project #435389

Research Project: Defining the Relationship of Productivity With Water Availability Across the Semiarid Western U.S.

Location: Southwest Watershed Research Center

Project Number: 2022-13610-012-35-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2018
End Date: Aug 31, 2023

Objective:
In semiarid ecosystems, interannual variation of productivity (carbon uptake) may be 3-5 times larger than previously thought. Dryland regions such as in the Southwest U.S. are important to Earth’s productivity and carbon cycling because they cover more than one-third of all land, and their biological activity depends on highly variable climate. We lack understanding of how climate variability affects the carbon cycle in dryland agroecosystems because 1) Until recently, direct measurements of water and carbon fluxes lagged far behind measurements in wetter regions, and 2) State of the art methods for upscaling flux measurements perform poorly in drylands. Now, there is an opportunity to leverage new datasets of carbon and water flux measurements from the Southwest U.S. as well as advances in remote sensing-based methods of flux upscaling including new platforms, sensors and modeling tools. The objectives of this project are to: 1) Assemble, update and analyze a dataset of water and carbon flux measurements from a network of more than 25 sites across diverse ecosystems of the Southwest U.S.; 2) Test and improve emerging remote sensing technologies based on land, aerial drones, and satellites; and 3) Develop improved estimates of carbon and water fluxes across the Southwest.

Approach:
We will link measurements made at more than 25 eddy flux towers across the Southwest U.S.states of California, Arizona, New Mexico, Utah and Colorado with remote sensing observations. Specifically, we will: 1. Update and expand our existing network of semiarid eddy flux towers and collaborators contributing to the world’s most comprehensive dataset of dryland carbon and water flux measurements. We will add LTAR and NEON datasets that have become available since 2014, the end of our existing dataset. 2. Test existing and emerging remote sensing technologies based on land, unmanned aerial drones, and spaceborne satellites for measurement and prediction of carbon and water fluxes, specifically gross primary productivity (GPP) and evapotranspiration (ET), at selected flux tower sites. 3. Combine flux and remote sensing measurements to evaluate and improve remote sensing based models of regional-scale carbon and water cycling.