Profile measurements of blowing snow at Halley, Antarctica

Measurements of blowing snow particle concentration from the second Stable Antarctic Boundary Layer Experiment (STABLE 2) are presented. The measureme nts, made at Halley Station (75.6 degreesS, 26.7 degreesW) throughout the 1 991 austral winter, are supplemented with profile measurements of wind spee d, air temperature, and humidity. Threshold wind speeds for blowing snow ar e shown to be distinctly different for various episodes, often depending st rongly on the the availability of loose snow. Blowing snow is measured to o ccur at Halley between 27 and 37% of the time during winter. Total winter ( June, July, August) blowing snow sublimation at Halley is calculated to be around 4.7 mm water equivalent, 3.7% of total accumulation over the same pe riod. Total winter blowing snow mass transport is calculated to be around 5 .5 x 10(5) kg per metre width. Measured humidity profiles at Halley show th at during winter blowing snow conditions, a layer of near-saturated air for ms, causing total sublimation to be less than that for seasonal or limited fetch snow covers. The extent of sublimation is shown to be strongly depend ent on wind speed, temperature and fetch.