Developing a New Snow Cover Fraction Scheme for Hydrological Predictions
Abstract
Reconstruction of snow cover fraction (SCF) using historical records of snow depth (SD) is important for investigating long-term snow cover variations under climate change. The SCF-SD relationship, when used in climate models, substantially affects the snow albedo feedback strength, the energy balance on ground bare soil and vegetation canopy thereby determining the simulation results for snow water equivalent (SWE). In addition, it is critical for predicting snow accumulation/ablation and river discharge at catchment and river basin scales. The SCF-SD relationship is strongly affected by surface roughness and subgrid topography and varied with snow accumulation/ablation seasons. However, the SCF-SD parameterization schemes are not adequately developed or assessed for lack of accurate, high-resolution data.
In this study, we use the University of Arizona (UA) ground-based daily 4-km SD/SWE dataset, the Moderate Resolution Imaging Spectroradiometer (MODIS) regular latitude-longitude global grid daily SCF dataset (Terra, collection 6 version) and the Interactive Multi-sensor Snow and Ice Mapping System (IMS) gridded daily 4-km snow cover extent (SCE) dataset to develop a new SCF-SD scheme based on two existing schemes and machine learning techniques at 4-km4-km spatial resolution for land surface modeling. We first check the consistency between datasets. Prior to coupling the Noah-MP with WRF-Hydro for testing how different SCF-SD formulations affect the streamflow hydrograph over a snow-dominated catchment, we evaluate all SCF-SD formulations in offline Noah-MP configuration by examining 1) the seasonal, interannual, and interbasin variations in SCF, SD and SWE against reference datasets, 2) the simulated long-term trend of SD and SWE against UA snow product, and 3) the changes of net radiation, turbulent fluxes (latent heat and sensible heat), ground heat fluxes and soil/ground temperature for accumulation and ablation seasons.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H33I2031W
- Keywords:
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- 0736 Snow;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 1860 Streamflow;
- HYDROLOGY;
- 1863 Snow and ice;
- HYDROLOGY