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.