Characteristics of orographic cloud and precipitation in the Arctic during STAR

Forecasting the onset, duration and amount of precipitation associated with upslope flow in the Arctic is a continuing operational and modelling challenge. The harsh climate, complex topography and expense related to maintaining ground-based instruments make it difficult to collect data that contains the level of detail required to verify model output. During the Storm Studies in the Arctic (STAR) project (2007-2008), orographic precipitation, as well as other weather features, were sampled in the eastern Canadian Arctic. The project focused on southern Baffin Island, Nunavut, which contains some of the highest mountains in Canada after the Rockies. Orographic cloud and precipitation was profiled using the National Research Council of Canada's (NRC) Convair-580 aircraft. Data from five research flights are used to identify the physical processes associated with terrain induced or enhanced precipitation in the Arctic. Measurements from dual wavelength (W and X-band) Doppler radar detailed cloud dynamics and structure during events. Dropsondes were released in various regions, to characterize the thermodynamic state of the atmosphere both upstream and over topography. Using 2-D cloud particle imaging probes, a comprehensive investigation of the microphysical characteristics was completed, including: particle type, concentration and size. The presentation will highlight results to date from theses case studies during STAR.