Underway snowfall measurements during the SIPEX II voyage of the Aurora Australis, 2012

Brief description

Note - these data should be used with caution. The chief investigator for the dataset has indicated that a better quality dataset exists, but the AADC have been unable to attain it for archive. Matlab file containing raw data snowfall data collected aboard the RV Aurora Australis using Campbell Scientific dataloggers. Two Wenglor brand YHO3NCT8 photoelectric sensors were mounted on the forward railing of the ship's "monkey deck". The beam heights of the sensors were 18cm above the upper railing, oriented parallel to the railing (perpendicular to the long-axis of the ship), approximately 6m apart. The port sensor was purchased in 2012, from a batch of these sensors manufactured in a new Eastern European factory while the starboard sensor came from a lot purchased in 2007, manufactured in Wenglor's German factory and extensively tested for use in snow. Pulse counts measured by the port sensor were consistently lower in magnitude than those recorded during the same interval by the starboard sensor. It is not currently clear whether this was due to the ship's tendency to be oriented with the wind to starboard, or whether this is due to differences in instrument characteristics. Data recorded between 17/9/2012 and 26/10/2012 was logged by a CR10x datalogger. Data recorded after 26/10/2012 was logged by a CR1000 datalogger. Information on converting the pulse-count data into a mass flux of snow is contained in Leonard, K.C. and R.I. Cullather (2008) Snowfall measurements in the Amundsen and Bellingshausen Seas, Antarctica. Proceedings of the Eastern Snow Conference, 65, 87 - 98. These two datasets are identical, but have been separated into two matlab structures contained in the same "shipsnow.mat" file: "snow" and "snow2". Data contained in these structures includes the following variables, with units: Datenm: matlab 'datenumber'. Change to conventional format using the "datevec()" command Port: beam interruptions per 10s interval, port-side sensor Stbd: beam interruptions per 10s interval, starboard-side sensor Ptemp: temperature of a thermistor mounted beneath the datalogger's wiring panel. The datalogger was contained in a fiberglass box, strapped into the starboard side observation shelter on the monkey deck. Volt: voltage received and transmitted by the datalogger. Power came from a 12v 1Ah converter plugged into the ship's power supply. The data have also been reformatted into two csv files.