The NASA ARID (Adaption and Response in Drylands) Scoping Project Overview (Website HERE)
ARID is a scoping study selected by NASA’s Terrestrial Ecology (TE) Program to work with dryland scientists and stakeholders and the remote sensing community to outline a future NASA field campaign focused on drylands. If NASA selects this study, they will commit significant funds to a multi-year field campaign aimed at improving our understanding of drylands via integrated measurements across spatial scales (e.g., plot, tower, drone, aircraft, and satellite scale). Previously funded campaigns include the Arctic Boreal Vulnerability Experiment (ABoVE), the Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA), and the Boreal Ecosystem-Atmosphere Study (BOREAS). Our scoping study will take place until approximately December 2024 when a final report will be submitted to the NASA TE Program.
Global photosynthesis, CO2, and carbon-climate feedbacks
We are building on our previous efforts to combine remote sensing observations, terrestrial biosphere models, tree ring isotopes, eddy-covariance observations, data from Free Air CO2 Enrichment experiments, and observations of the seasonal cycle of atmospheric CO2 to constrain the historic response of photosynthesis to rising CO2. We will then apply our findings assess and reconcile differences across remote-sensing and terrestrial biosphere model based estimates of long-term changes in global photosynthesis. As part of this work we will develop a CO2 sensitivity function that can be implemented in any established satellite-based approach. We propose to use the resulting characterization of the response of ecosystem structure and function to CO2 to test hypotheses regarding the relationship between CO2 and carbon-climate feedbacks.
Leveraging Field Experiments, Satellite Data, and Models to Improve Understanding of the Role of Semi-Arid Ecosystems in Global Carbon Cycle Variability
Dryland ecosystems represent Earth’s largest biome, making up over 40% of the planet’s terrestrial surface and supporting the livelihoods of billions of people. Semi-arid regions have been shown to play a dominant role in the inter-annual variability (IAV) and long-term trend of the terrestrial carbon, C, sink, yet our understanding of C cycling in these water-limited ecosystems remains notably poor. We are integrating remote sensing, on-the-ground measurements, and modeling for a coordinated set of core sites in the southwestern US to assess the key contributions of different cover types to semi-arid ecosystem C cycling. We are next linking ground-based analyses with satellite data to improve remote sensing C products at the regional to global scale. We will then employ these data to test, optimize, and further develop process-based models to expand our understanding of the causes and contributions of semi-arid ecosystem C cycle variability at the global scale.
Mapping biocrust community composition and functional diversity across global drylands
Biological soil crusts (hereafter, biocrusts), are photosynthetic communities of cyanobacteria, lichens, and/or bryophytes that cover vast expanses of the terrestrial surface and play critical roles in soil stabilization, fertility, water cycling, and carbon exchange with the atmosphere. Biocrusts are found on all of Earth’s continents and are ubiquitous and play keystone roles in global dryland ecosystem structure and function. We are integrating Earth Surface Mineral Dust Source Investigation (EMIT) and other complementary satellite observation records with the larger goal of mapping biocrust community composition and functional diversity across global drylands. As part of this work we are conducting intensive field campaigns at multiple unique long-term dryland climate manipulation experiments and acquire new C flux, stock, and soil microclimate data from an existing global network of dryland eddy covariance sites.