Simulating the combined heat transfer and water balance at and below the land surface with GSSHA model
Abstract
Frozen soils and permafrost can have a large impact on soil hydraulic conductivities due to confining properties of ice in the soil, leading to alternations of the hydrologic response, such as reduced infiltration, increased overland flow, and changes to groundwater flow patterns. We included the capability to simulate the soil thermal regime, frozen soil and permafrost in the Geophysical Institute Permafrost Laboratory (GIPL) model into the physically based, distributed watershed model Gridded Surface Subsurface Hydrologic Analysis (GSSHA). The GIPL model simulates soil temperature dynamics, the depth of seasonal freezing and thawing, and permafrost location by numerically solving a one-dimensional nonlinear heat equation with phase change. The GSSHA model is a spatially explicit hydrological model that simulates two dimensional groundwater flow and one-dimensional vadose zone flow. The GIPL model is used to compute a soil temperature profile in every two-dimensional GSSHA computational element. GSSHA uses temperature and phase information to adjust hydraulic conductivities for both the vertical unsaturated soil flow and lateral saturated groundwater flow. The newly coupled system was tested and applied in both test case and experimental watersheds with discontinuous permafrost in Alaska USA. The simulation results indicated that freezing temperatures reduces soil storage capacity, thereby producing higher peak discharges and lower base flow.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C21A1101W
- Keywords:
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- 0702 Permafrost;
- CRYOSPHERE;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1829 Groundwater hydrology;
- HYDROLOGY;
- 1875 Vadose zone;
- HYDROLOGY