MODELING NORTHEASTERN U.S. SNOWPACKS AND FROZEN GROUND TO INFORM HYDROLOGIC PARTITIONING UNDER CHANGING WINTER CONDITIONS

Seasonal snowpacks are projected to decrease as we observe increasingly warmer winters due to anthropogenic climate change. In a paradoxical way, the reductions in snow cover in the Northeastern United States has been linked with an increase in the presence and duration of frozen ground. The increase in ground frost has been well correlated to reductions seasonal snowpack, particularly with snowpack thickness and persistence, even despite slight increases in winter temperatures. Snow insulates the ground from the freezing winter air temperatures and prevents the ground from freezing. Changes in frozen ground dynamics will change how snowmelt is partitioned between runoff, infiltration, and groundwater recharge. Quantifying these hydrologic responses requires accurate characterization of snowpack and snowmelt dynamics. Our objective is to use a combination of process-based modeling and field observations to quantify and track the changes in snow, snowmelt, and ground frost dynamics in the Northeastern United States. Specifically, we plan to model the snowpack in two northeastern US watersheds: Sleepers River Research Watershed (SRRW) in Vermont and Hubbard Brook Experimental Forest (HBEF) in New Hampshire. We will utilize existing historical and current observations at both sites to understand how snow and ground frost dynamics have changed with time. We will outline our research plan that supplements the ground surveys at SRRW and HBEF. We will present current work taken at both sites, including our current efforts in monitoring the snowpack thickness and temperatures, and outline future work such as lidar surveys that will help calibrate and validate the snow models. Our snow modeling work would then serve as inputs for a subsurface hydrologic model to model the changes This work will enhance our understanding of the long-term changes to the winter hydrology of the northeastern U.S. and will be useful to inform the development of sustainable water resource management strategies in a warming climate, that may be applicable across the Northeast.