A climatology of significant winter-type events for the Mackenzie River Basin inferred from the ECMWF Re-Analysis data

Stephen J. Déry and M. K. Yau


A global and regional climatology of some significant winter-type events will be presented. Using gridded data from the European Centre for Medium Range Forecasts (ECMWF), a global compilation of blowing snow, blizzard and high windchill events is conducted for the period 1979-1993. The results show that these phenomena occur primarily over flat, open surfaces with long seasonal or perennial snowcovers such as the Greenland and Antarctic icefields as well as the Arctic tundra. On a regional scale, emphasis is given to the Mackenzie River Basin (MRB) of Canada where fewer of any of the events take place within the boreal forest as opposed to the Arctic tundra. Interannual and monthly variabilities in the number of events are also evident and are due primarily to 10-m wind speed anomalies at high latitudes for blowing snow and blizzard events while high windchill events are more sensitive to air temperatures near the surface. Compositing of the principal surface meteorological fields show that anticyclones and lee cyclogenesis are prominent features associated with blowing snow events in some sections of the MRB.