Global ecosystem function is highly dependent on climate and atmospheric composition, yet ecosystem responses to environmental changes remain uncertain. Water, in particular, provides a strong…

The University of California, Berkeley received a $177,012.93 research grant (19-SMAP19-0048) from a civilian federal agency to identify global controls on vegetation productivity through Soil Moisture Active Passive (SMAP) satellite observations. The project leverages SMAP's soil moisture and freeze-thaw state measurements in combination with observations from the Moderate Resolution Imaging Spectroradiometer (MODIS), Visible Infrared Imaging Radiometer Suite (VIIRS), and other Earth observation missions to characterize water limitation of terrestrial ecosystems. This research directly supports understanding how water availability constrains vegetation cover and ecosystem productivity across diverse climate zones—from semi-arid regions dependent on soil moisture to cold regions dependent on freeze-thaw dynamics.

The award was not designated as a set-aside and represents a competitive research grant with a performance period ending September 8, 2023. UC Berkeley's research team will develop vegetation functional response metrics and create benchmarks for Earth system models, with particular focus on spatial responses to soil moisture changes in arid regions and freeze-thaw state changes in cold regions. These benchmarks will be implemented into the Integrated Land Model Benchmark (ILAMB) platform to improve model-data intercomparison capabilities, ultimately advancing understanding of the global carbon cycle and ecosystem responses to environmental change.

Global ecosystem function is highly dependent on climate and atmospheric composition, yet ecosystem responses to environmental changes remain uncertain. Water, in particular, provides a strong constraint on the amount of vegetation that can be maintained in an ecosystem and its productivity. Indeed, water availability limits plant growth and productivity in almost all terrestrial ecosystems. Both the amount of water, in the form of soil moisture, and its state are important. For example, ecosystems in semi-arid regions are highly dependent on the amount of moisture in the soil, while ecosystems in cold regions are dependent on the freeze-thaw state. Smap represents an unparalleled opportunity to understand ecosystem responses to water availability, in particular through fusing smap observations with modis/viirs observations and global earth system models. We propose to leverage that opportunity, using global smap L3 products of soil moisture and freeze-thaw state, together with the L4 net ecosystem exchange product, in combination with modis, viirs and other missions to characterize the extent and dynamics of water limitation of global terrestrial ecosystems. Previous efforts by this team have developed vegetation functional responses from modis and gimms, and used them to quantify the response of vegetation cover to spatial and temporal changes in climate and precipitation. This project will combine the strength of this analysis with smap, allowing US to assess the control global water availability exerts over vegetation cover, ecosystem productivity, and the global carbon cycle. Particularly, benchmarks will be developed for earth system models, focused on spatial responses of vegetation state and function to changes in soil moisture in the worlds dry regions, and spatial responses to changes in freeze-thaw state in the worlds cold regions. These benchmarks will be implemented into the integrated land model benchmark (ilamb), a model-data intercomparison and integration platform in which this team is heavily involved. Ilamb is designed to improve the performance of land models and, in parallel, improve the design of new measurement campaigns to reduce uncertainties associated with land surface processes.