Abstract:

A blizzard case at Great Wall Station was studied using data of NCEP analysis, in-site observations, surface weather charts and statellite images. The blizzard weather took place on August 29th,2006, and resulted in highest wind speed (33.3m/s) and the worst horizontal visibility (<10m). It’s found that this blizzard was under the situation of ‘High in the south, low in the north’, and the easterly gale caused by the weather situation was the precondition to the blizzard occur. The low level easterly jet from the Antarctic continent brought significiant decrease in air temperature and humidity, made the blizzard with obvious feature of low temperature and humidity. The warm air advection at high levels brought enough mositure from lower latitudes. The deep cyclonic vorticity at middle and low level, the pattern of divergence at high level and convergence at low level, and strong vertical uplifts were the dynamic reason of the strong snowfall and blizzard. There was a inversion layer in the low atmospheric level during the later half of the case which essential was the air mass vertical structure of “cold at low level, warm at high level”, it’s very important to the lasting of the blizzard.

Key words: Keywords: Blizzard, Blowing Snow, Cyclone, Antarctic, Great Wall Station