Project period: 8 1 24-11 30 26PROJECT title: evapotranspiration in wetlands: a CONUS-wide assessment of openet models, evaluated with a meso-network of eddy covariance towers and statistical…

This federal Cooperative Agreement award from the U.S. Geological Survey (USGS) under the Research and Data Collection program (CFDA 15.808) provides $289,379 to the University of California, Berkeley to conduct research on characterizing evapotranspiration across wetlands in the contiguous United States. The project aims to leverage eddy covariance measurements and remote sensing models to enhance the accuracy of wetland evapotranspiration estimates, addressing the challenges posed by the heterogeneous nature of wetland ecosystems. Key activities include assessing the performance of OPENET remote sensing models, partitioning evapotranspiration into evaporation and transpiration using advanced modeling approaches, and exploring cost-effective measurement techniques. The findings will help improve understanding of wetland evapotranspiration and support more reliable data to inform decision-making for wetland management and restoration efforts. The award period runs from Aug 1, 2024 to Nov 30, 2026.

Project period: 8 1 24-11 30 26PROJECT title: evapotranspiration in wetlands: a CONUS-wide assessment of openet models, evaluated with a meso-network of eddy covariance towers and statistical biophysical models.accurate estimates of wetland evapotranspiration remain challenging due to the heterogenous nature of wetland ecosystems. In this project, we propose to characterize evapotranspiration and its mechanism across wetlands in the U.S. By leveraging eddy covariance measurements and openet remote sensing models.for available wetland sites, will use measured evapotranspiration from eddy covariance to assess the performance of openet models. To inspect how different structure assumptions of each openet model affect the modeled evapotranspiration, we will conduct sensitivity analysis by linking modeled results to in-situ environmental and micrometeorological variables. These findings will help provide recommendations for modifications to openet model algorithms or the development of wetland specific remote sensing evapotranspiration products.to investigate how spatial heterogeneity affects wetland evapotranspiration, will focus on partitioning evapotranspiration into evaporation and transpiration using two state-of-the-art models. The first approach uses artificial neural networks to predict daytime evaporation from nighttime evapotranspiration measurements. The second approach uses a multi-layer biophysical model to compute transpiration based on leaf area index profiles obtained from light detection and ranging observations. By exploring both models, we will provide insights into different evapotranspiration partitioning schemes in wetland ecosystems. Energy balance closure issues will be explored using data from a tidal wetland before and after flooding. We will use wavelet analysis to decompose measured fluxes at diel and multiday scales. Then, mutual information theory will be used to examine how different environmental and micrometeorological forcings affect the surface energy balance. The findings will help characterize the components affecting surface energy balance and identify needed measurements. Cost-effective evapotranspiration measurement will be explored using the variance-bowen ratio technique across various wetland sites in the sacramento-SAN joaquin delta region. The performance and robustness of this technique will be assessed against concurrent eddy covariance measurements. The findings can help increase evapotranspiration measurements in wetland and provide additional validations and calibrations for openet models.to synthesize mechanisms of evapotranspiration, will use non-parametric statistical models to quantify functional relationships of land-atmosphere interactions in wetlands across climate and ecological gradients. This will help improve understanding of evapotranspiration and provide optimal input variables for quantifying energy and water fluxes across spatial and temporal scales using remote sensing models. This project aims to enhance the accuracy of wetland evapotranspiration estimates, addressing the challenges posed by the heterogeneous wetland ecosystems. By advancing the understands towards wetland evapotranspiration, this project will support more reliable data on wetland evapotranspiration. Additionally, policymakers and water resource managers will benefit from the improved data, enabling better decision making for wetland management and restoration efforts.