6.3      The representation of precipitation characteristics in high resolution WRF simulations over western Canada.

Erler, Andre R., Aquanty Inc., Canada, and Brian Menounos, University of Northern British Columbia, Canada

Orographic precipitation is the dominant form of precipitation in western North America and provides most of the water resources in this region.
However, precipitation at high elevation is difficult to observe and due to the importance of small-scale processes, it is also very challenging to model numerically.

Here we employ a set of high-resolution WRF simulations over the Columbia and Coast Mountains in British Columbia, Canada, to investigate the representation of precipitation over complex terrain.
The WRF model (V3.6.1) is configured with an outer domain at 7km and inner domains at 1km resolution and was forced with ERA-Interim data from 2010 to 2016.
We compare the simulated precipitation fields against gridded datasets (NRCan, PRISM), in-situ observations (ECCC and SNOTEL), as well as SWE estimates from SNODAS.

Our analysis shows that many characteristics of orographic precipitation are reproduced, including slope dependence and elevation dependence.
However, precipitation in the Coast Mountains is still underestimated, even at 1km, while precipitation at high elevation in the Columbia mountains exceeds estimates from gridded observational products.
Furthermore, to the extent that in-situ observations are vailable, a statistical extreme event analysis will be conducted.