Atmospheric turbulence above Dome A from a sonic radar

Brief description

This directory contains raw and reduced data from two sonic radars (the instrument is called "Snodar") that were installed at the Chinese station at Dome A. Snodar was built and designed by Colin Bonner, a PhD student at UNSW supervised by Michael Ashley. Contributions were made by the authors on the scientific papers in the "papers" directory. The data are freely available for use. If you publish a paper using them, please cite our Snodar papers (see below). The purpose of Snodar was to determine the turbulence in the atmosphere above the ice level, to a height of 180m, with a resolution of 1m. The minimum observable height was about 8m. Snodar sent out an acoustic pulse at about 5 kHz, and listened for the echo. The directories here are: /papers PDFs of papers and a PhD thesis describing the instrument and results /2009_Data_analysis Reduced data /snodar Raw data /snodar09 Raw data /extracted Raw data The raw data contain echo strengths, and are in files with names similar to the following: output/SNODAR_DATA_1203077424_265709 output/RAW_SNODAR_DATA_1255074792_749298 The filenames end with the UNIX time epoch (in seconds, followed by microseconds after the "_") of the start of the observation. There are also some WAV files such as: snodar-1205534620.wav.bz2 which contain the raw acoustic echoes from the Snodar. Snodar was first deployed to Dome A in early 2008. It measured a stable diurnal boundary layer with a minimum height of 9 m and a maximum height of 89 m between the 10th and 14th of February 2008. A minor electrical failure crippled the instrument after 12000 samples. The instrument could not be repaired until 2009 as Dome A is an unmanned site. A second-generation of Snodar was deployed to Dome A in January 2009 and included several modifications to expand its capabilities and increase its robustness. The modifications included a new antenna design to hinder frost formation. The 2008 Snodar was also upgraded and as such there were two Snodars operating simultaneously at Dome A during 2009, with a separation of approximately 20 m. The agreement between the two instruments was extremely good. The data files are a "1" or "2" in their filenames to distinguish them. The pre-2009 Snodar is number 1. The reduced data are in the form of CSV files showing boundary layer height and UNIX epoch, with postscript plots. See the matlab file "2009_Data_analysis/monthly_anal.m for" the data analysis program. Sub-folders within "2009_Data_analysis" show results with alternative definitions for the boundary layer height. For help, email Michael Ashley and/or Colin Bonner .