HR: 0830h
AN: C41B-0947 INVITED     [PDF]
TI: Snow Processes: Current Understanding and Future Prospects
AU: * Pomeroy, J W
EM: pomeroy@usask.ca
AF: Department of Geography, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK S7N 5A5 Canada
AB: Snow processes are the key to understanding and describing the hydrology and climatology of cold regions and seasons. Snow is not simply a solid precipitation that can be treated like other hydrological inputs, but is redistributed, sublimated, and metamorphosed after snowfall and undergoes complex and rapid changes during melt. In open landscapes blowing snow erodes and transport surface snow from exposed surfaces through two-phase flow and redistributes the snow to more sheltered surfaces. During transport, significant sublimation loss may occur, making the process not just one of redistribution but ablation. Rapid changes to snow density, crystal size and spatial statistical properties occur during this phenomenon. In forested regions, snow interception by the canopy can store the majority of a mid-winter snowfall, and intercepted snow is exposed to high energy inputs, driving enhanced sublimation and melt. All snowpacks are subject to complex radiative, turbulent and conductive energy transfers which couple with snow mass transfer in manners that are not fully understood. It is increasingly realised however that simple flat plane assumptions in calculating coupled heat and mass transfer are not adequate for describing snow dynamics. Further, the non-linear aspects of most snow processes make their larger scale description highly dependant on the spatial distribution of boundary conditions and how these in turn are affected by the evolving snowpack state. The upcoming challenges in the study of snow processes still include improving the basic descriptions of these processes, yet new challenges have arisen in understanding and describing snow processes and their space-time dynamics over highly heterogeneous landscapes. The remarkable consistency of larger scale descriptions of snowcover evolution and spatial variation suggests that there are relevant principles of spatial organisation whose importance to snow phenomena has not been identified or explained.
DE: 1833 Hydroclimatology
DE: 1863 Snow and ice (1827)
DE: 1878 Water/energy interactions
DE: 3322 Land/atmosphere interactions
DE: 3354 Precipitation (1854)
SC: Cryosphere [C]
MN: 2003 Fall Meeting