Carbon Monitoring System in Mountains (CMS-Mountains): Leveraging Satellite-Based Solar-Induced Fluorescence to Understand Forest Drought and Mortality in the Western U.S.

Despite the need to understand terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO2 concentrations, knowledge of these fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where complex atmospheric flows and relative lack of observations lead to significant uncertainties in carbon fluxes. Many mountainous regions also have significant forest cover and biomass, yet these potential carbon sinks are highly dynamic and vulnerable to disturbance events, such as drought, insect damage, and wildfires. Our new Carbon Monitoring System over Mountains (CMS-Mountains) seeks to leverage the information in remotely-sensed solar-induced fluorescence (SIF), along with other observational data, to predict carbon fluxes over the Western U.S., with a particular focus on ecosystems in Californias Sierra Nevada region. The information in the observations is incorporated into the latest release of the Community Land Model (CLM 5) using advanced data assimilation techniques within the Data Assimilation Research Testbed (DART). We will report on several advances in the project: 1) initial estimates of carbon fluxes and biomass stocks across the entire Western U.S. via assimilation of leaf area index and above-ground biomass, 2) topography-corrected SIF that accounts for effects such as hill-shading and slope orientation within the satellite footprints, 3) upgrades to the DART data assimilation system, 4) engagement with partners in the Sierra Nevada region.