Impact of precipitation forcing on gridded snow water equivalent estimates across North America
Abstract
Historical gridded products of snow water equivalent (SWE) at continental scales are used in many applications (e.g. climate assessment, drought monitoring, streamflow seasonal forecasting). Such SWE products can be obtained from a land surface model driven by an atmospheric reanalysis. Two strategies are generally considered for the precipitation forcing: (i) direct precipitation from the atmospheric reanalysis or (ii) bias-corrected precipitation based on observation datasets. However, due to the scarcity of precipitation gauges in snow-dominated regions (northern latitudes, mountainous regions) and the challenges associated with the measurements of solid precipitation, the use of bias-corrected precipitation may degrade SWE estimates. The recent release of the 10-km RDRS (Regional Deterministic Reanalysis System) reanalysis over North America provides a unique opportunity to investigate this question in detail. The RDRS reanalysis includes two precipitation fields: (i) direct (forecasted) precipitation from the Global Environmental Multiscale (GEM) atmospheric model and (ii) analysis from the Canadian Precipitation Analysis System (CaPA). These two precipitation fields are used in combination with other RDRS atmospheric forcings to generate two SWE estimates, one from each precipitation forcing, with the Soil, Vegetation and Snow (SVS) land surface scheme at 10 km resolution over North America for the period 2000-2018. Simulated SWE is compared with manual and automated observations from a newly developed database comprised of over 2500 monitoring sites across North America. Differences in SWE error metrics between both simulations are analysed as a function of station density in CaPA and results are synthesized for different snow classes and topographic regions. SWE estimates from the ERA5-Land reanalysis are also considered as a benchmark. The results will help to guide the generation of a new North American snow product.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H34B..03V