Advances in Spatial Snow Modeling in Mountain Terrain

TitleAdvances in Spatial Snow Modeling in Mountain Terrain
Publication TypeConference Proceedings
Year of Conference2009
AuthorsKienzle, S. W.
Conference Name77th Annual Western Snow Conference
Series TitleProceedings of the 77th Annual Western Snow Conference
Date PublishedApril 2009
PublisherWestern Snow Conference
Conference LocationCanmore, AB
KeywordsSnow modeling, Rocky Mountains, precipitation type, lapse rate, air temperature, ACRU

Snow modeling is a demanding task in itself, but is even more demanding in complex terrain such as the Rocky Mountains. Snow modeling is carried out here with the ACRU agro-hydrological modeling system. A critical advancement was the development of a new method to separate snow and rain (Kienzle, 2008). As a further improvement, a new GIS based method that determines two daily minimum and maximum temperatures, based on incoming radiation calculations and leaf area index adjustments, is presented. This results in a daily, lapse rate dependent, air temperature to determine the precipitation type (snow or rain), and a near-ground air temperature to determine snow melt and evapotranspiration rates. A drawback in most distributed hydrological models is that area calculations are based on the horizontal plane rather than the sloped area. A method is presented to use two area calculations for each hydrological response unit: a horizontal area, which is used for precipitation input calculations, and a larger sloped area, which is used for all other hydrological processes, including interception, sublimation, snow melt, soil moisture, or groundwater recharge.