Snowfall Measurements in the Amundsen and Bellingshausen Seas, Antarctica

• Main Authors: Katherine C. Leonard, Richard, I. Cullather
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarc*; Antarctica; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.583.7714; http://www.utsa.edu/lrsg/Antarctica/SIMBA/publications_abstracts/Leonard_Cullather_ESC2008_final.pdf

Unique in situ oceanic snowfall measurements in high southern latitudes are presented from two research cruises to the Ross, Amundsen, and Bellingshausen Seas aboard the R/V Nathaniel B. Palmer in 2007 (NBP0702 and NBP0709). The number of falling snowflakes passing through the beam of a photoelectric particle counter mounted approximately 30m above sea level was continuously logged during these cruises, and is compared here with model forecast precipitation and with observations of accumulation on the adjacent sea ice. The model precipitation is from daily operational model output of the European Centre for Medium-Range Weather Forecasts (ECMWF). The daily total precipitation measured by the particle counters and calculated for each cruise using two different size distributions is compared with the ECMWF predictions. Synoptic storms led to significant precipitation events during both cruises, and there is good correspondence between the timing of the related maxima in the observed and forecast time series. Overall, the correlations were r=0.19 for NBP0702 and r=0.69 for NBP0709. Calculations of the precipitation mass flux based on the observed snow counts are strongly dependent on the effective size distribution of the precipitating snow, a poorly known variable for this region.