Integrated Ground, Sub-Orbital, and Orbital Land-Atmosphere Feedback Observatories to Advance Understanding of Agriculture-Climate Interactions in the U.S.

As the global weather and climate modeling enterprise strives to develop 1-km scale digital twins of the Earth system, it is vividly apparent that parallel investments in our observational systems are critically needed to keep pace in resolution and accuracy. There is a particular need to focus observational efforts on major drivers of regional weather and climate that most of these models omit, namely, large-scale agriculture. Agricultural land management, and associated water resources management, can significantly impact sensible weather in all seasons from field- to mesoscale. The impacts derive from spatially heterogeneous land-atmosphere interactions that occur within the Planetary Boundary Layer (PBL) and are influenced as much by local land state (i.e., soil moisture and vegetation structure) as large-scale atmospheric forcing (i.e., advection). The complete chain of coupled processes span from the groundwater to the land surface, through the PBL, and to the top of PBL entrainment fluxes. As land-atmosphere interactions upscale, so do there impacts. Prior studies have demonstrated impacts on mesoscale low-level jets and synoptic scale tropical storms. Simply stated, model realism, and the efficacy of satellite land data assimilation, depends on the accuracy of a model’s land-atmosphere coupling strength.

The single greatest barrier to model development and process understanding is that observational constraints for the land-atmosphere coupled process chain remain globally scarce. Fluxnet sites with soil moisture probes capture only the terrestrial segment. Fluxnet locations with ceilometers additionally capture the atmospheric segment, partially. Field campaigns LIAISE (Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment) and CHEESEHEAD (Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors) capture the full coupling chain for short periods. Only ARM-SGP (Atmospheric Radiation Measurement-Southern Great Plains) provides long-term continuous observations of the full coupling chain. The need for additional long-term land-atmosphere feedback observatories spanning diverse climates is well appreciated across several U.S. agencies including NOAA, NASA, DOE, and USDA. The key outstanding questions are: 1) Where does the hydrometeorological community prioritize siting of a limited number of observatories?; 2) What are the critical measurements, observing strategies, and data products?; 3) How will these observatories interface with other federal, state, and private surface observational networks; airborne, and satellite platforms?; and 4) What is the funding required?

This presentation will address these questions by providing an overview of the design specifications for a proposed land–atmosphere feedback observatory in Goodwater Creek Watershed of Centralia, Missouri. Goodwater Creek has significance as a USDA experimental watershed (since 1971) and a USDA Long-Term Agroecosystem Research site (since 2015). The proposed observatory is envisioned as the anchor of a U.S. agriculture–climate feedback-focused transect of similar observatories north-south along the Mississippi River valley. The design plans will be discussed in the context of the proposed GEWEX U.S. Regional Hydroclimate Project, the international GEWEX (Global Water and Energy Exchanged program) Land Atmosphere Feedback Observatory (GLAFO) network, and NASA’s PBL Incubation Study Team. Full leveraging of the proposed observatories will require a new generation of interdisciplinary observationalists and modelers that specialize not just in single instrument applications, but in the application of synergies of ground and satellite instruments through data assimilation. A white paper will be released for public comment at the AMS 2024 meeting. This scoping study was supported through funding from the NASA Terrestrial Hydrology Program.