Blowing snow instrumentation and study in Iqaluit

A field study has been conducted in Iqaluit (63° 45' N, 68° 31' W) from October, 2007 to April, 2008. A piece of ground to the west of Iqaluit airport station was chosen for the field study. Sensors were set up to measure wind speed, temperature, humidity, pressure, number of snow particles, visibility and electric field. Data were recorded throughout the whole period of study. From the analysis of the collected data, several parameters were calculated to characterize blowing snow event. Wind flow was mainly from the north west with some occasional wind from the south-east. The threshold wind speed for the initiation of blowing snow was ranged from 5 to 11 ms -1 depending on the temperature, the time passed after the last blowing snow event and availability of loose snow on the ground. The average surface roughness length calculated from the wind profile was 0.13 mm and the threshold friction velocity ranged from 0.25 ms-1 to 0.50 ms-1 . Particle number density was calculated from the output of particle counters and compared with the visibility sensor data at the same height. A good correlation (r2=0.8) is found between those data. An inter comparison among the snow particle counters was carried out to determine the limitations of the particle counters. In summary modification to the particle counter circuit has been carried out so that all counters provide identical results at the same condition and also to improve the performance of the counters in cold temperature.