LandAquatic

Role of linked hydrological, permafrost, ground ice, and land cover changes in regional carbon balance across boreal and arctic landscapes

Duration: 11/01/2022- 10/31/2025
Award Amount: $913,015

Participants
Lead PI in collaboration with Tamara Harms at University of Alaska, Fairbanks, Mark (Torre) Jorgenson at Alaska Ecoscience and Neal Pastick at USGS

Project Objectives

This project targets the immediate and cascading effects of warming on terrestrial and aquatic ecosystems in Alaska. The proposed study will reduce uncertainty in estimated C emissions from high-latitude regions by integrating terrestrial and aquatic fluxes, and by characterizing long-term trajectories of permafrost and land cover change over heterogeneous landscapes. The proposed research is enabled by rich in situ, airborne, and satellite data on climate, permafrost, ground ice, hydrology, vegetation distribution, and C and nitrogen (N) dynamics produced in part by previous phases of the ABoVE program. We propose to quantify relationships among these components and to parameterize a suite of land surface models that estimate terrestrial, lateral, and aquatic fluxes of C.

The modeling efforts will reduce uncertainty in regional C balance by enhancing representation of: 1) land-water fluxes of C and N, and 2) spatial heterogeneity in long-term relationships among ecological dynamics and permafrost. Specific project objectives are to: i) assess interactions among remotely sensed thermokarst extent, ground ice melting, and land cover change with climate across contrasting soil landscape units; ii) describe long-term patterns in soil temperature and thermokarst formation; iii) characterize lateral fluxes of water, C, and N from watersheds; and iv) detect and model biogeochemical responses to disturbances and land cover change at watershed and regional scales.

Leveraging existing data, the study will advance understanding of climate-induced change in high-latitude ecosystems with three key innovations. First, the proposed study will compile a first-of-its-kind dataset of thermokarst and ground ice melting features and land cover changes to drive ecosystem models at site, watershed, and regional scales for the last few decades. Second, this study will use empirical relationships between water, lateral C and N fluxes, and permafrost degradation conditions revealed by long-term monitoring of watersheds to revise regional-scale dynamics of water, C and N across boreal and arctic landscapes.

Finally, we propose to examine mechanisms by which changing ground ice conditions influence lateral flux of water and solutes using a 3-dimensional model validated by existing high-frequency watershed monitoring data. The proposed efforts are therefore among the first to integrate empirical observations with process-based models to estimate the role of land-water interactions in regional-scale models of C balance. Overall, the proposed research will demonstrate empirical and modeling approaches that reduce uncertainty in estimated C emissions by explicitly accounting for the influences of permafrost and land cover change on hydrology and terrestrial-aquatic coupling, and are applicable across the ABoVE domain and pan-Arctic regions. This proposed research specifically targets the ABoVE Phase 3 research topics of (1) that is to integrate previous ABoVE research results and remote sensing data into a coherent modeling framework to diagnose and predict ecosystem dynamics and (4) that is to use satellite and airborne remote sensing within the ABoVE domain to fill critical gaps in our understanding of northern ecosystem dynamics.