Cloud Mass Meridional Transport events (CMMTs) as defined in Staude (2007) are recorded in the following comma-separated values (CSV) files. CMMTs are manually observed using infrared satellite imagery created by blending geostationary and polar orbiting satellites into a single satellite composite at the Antarctic Meteorological Research and Data Center (Kohrs et al., 2014). The purpose of this dataset is to improve forecasting capabilities over Antarctica and to verify atmospheric conditions found in reanalysis and weather forecasting models. Satellite data offers an alternative way of viewing cloud masses over a data sparse region of the world.
Here, CMMTs are classified by their total duration (i.e., two days long), the region(s) they make landfall in, and the total number of events per month and year. There are 11 CSVs. Seven of the CSVs depict the seven regions found in the table and figure below. The other four pertain to West Antarctic Skirting events, East Antarctic Skirting events, all Antarctic Skirting events (West + East Antarctica), and all Antarctic CMMTs.
The following information is based on viewing the CSV file in an interactive development environment for the Python programming language (JupyterLab, Visual Studio Code, etc.).
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The name of the region will be in the title of the CSV file.
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From left to right, the following labels are used at the top of each of the 16 columns.
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Column 1: Month (numbered 1-12, where January = 1, February = 2, etc.)
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Column 2: Year (YYYY)
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Column 3-14: 2d to 13d (2-day events, 3-day events, …, 13-day events)
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Column 15: Days Affected
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Column 16: Number of Events
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There are 362 rows of data in each CSV, representing November 1992 – December 2022
Errors in the dataset are possible due to the subjectivity of manually identifying the time and position of every CMMT. Each observer is trained to observe CMMTs on a test month to mitigate biases before documenting new data. All months are reviewed twice or more to minimize any typos, misinput data, and miscellaneous errors. The CSVs are then cross-examined with the ASCII text files available here (https://doi.org/10.48567/jjkq-qp49) to ensure consistency between formats.
Citations:
Kohrs, Richard A., Lazzara, Matthew A., Robaidek, Jerrold O., Santek, David A. and Knuth, Shelley L. Global satellite composites - 20 years of evolution. Atmospheric Research, Volume 135, 2014, p. 8-34, https://doi.org/10.1016/j.atmosres.2013.07.023.
Staude, J., 2007: Poleward Propagating Weather Systems in Antarctica. M.S. thesis, Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, 90 pp, https://www.aos.wisc.edu/uwaosjournal/Volume4/theses/Staude.pdf