1. Australian Antarctic Data Centre
2. Discover and Manage Data
3. Records
4. SIPEX_II_Underway_Snowfall

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.

Quality

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.



When the instruments and CR10x datalogger were first plugged in to ship power on the 17th October, it appears that the CR10x datalogger's internal battery failed. On every subsequent power cut the timestamp reset to time 0,0,0,00:00. The files have been corrected for this, with the possible loss of up to several minutes data during power cuts of unknown duration, since the files were time-stamped assuming that the power cuts were each 10s or less in length.

A file download on the 25th of October indicated that more serious problems had resulted in the loss of 2-3 days of data immediately following the previous data download on the 11th of October. The re-awakening of the logger appears to have coincided with ship power testing on the 14th (during ice station 6).

On the 26th of October, the CR10x datalogger was replaced with a CR1000 datalogger, and data collection was restarted. Both the port and starboard sensors were powered, but it appears the starboard sensor was not being correctly logged, and data from the starboard side sensor was recorded as a string of zeros in the "snow2" matlab structure.

Access

These data are publicly available for download from the provided URL.

Temporal Coverages

• Start date: 2012-09-17 - Stop date: 2012-11-09

Spatial Coverages

Science Keywords

• EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > SOLID PRECIPITATION > SNOW
• EARTH SCIENCE > CRYOSPHERE > SNOW/ICE
• EARTH SCIENCE > CRYOSPHERE > SNOW/ICE > SNOW COVER
• EARTH SCIENCE > CRYOSPHERE > SNOW/ICE > SNOW DEPTH

Use Constraints

This data set conforms to the CCBY Attribution License
(http://creativecommons.org/licenses/by/4.0/).

Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=SIPEX_II_Underway_Snowfall when using these data.