FAMOUS

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Absolute_verylong filenames

The new Absolute_verylong format changes the UM date-coding conventions for the file names, and simply specifies the year as an 9 digit integer in the file name - for example: xbyvra@pyo71c1 becomes xbyvra#py000002471c1+. The long_output_names.mod also lets the UM use negative dates, so that actual paleo years can be specified - this is denoted with a “+” or “-“ at the end to signify whether it is an Common Era (AD) or BC date. Note that handling of negative, or BC dates thus differs from the standard paleoclimate convention of X yrs BP, where the Present in BP is generally taken as 1950 - for example, the LGM at 21kyr BP would be dated in FAMOUS as 19,050 BC. This is very annoying, but I couldn’t think of a good way to handle the discontinuity between modern dates and the BP convention. Of course, if you make sure that all your ancils, including the orbital ones (if calculated online the routine uses AD/BC dates) have the right offsets, you can use any date convention you like.

This new format is now selectable from the list in Sub-Model Independent → File and Directory Naming.

WARNING - Utilities based on conv.sh (including xconv) that convert UM files into other formats (i.e. netCDF) cannot cope with long (more than 4 digit) or negative years in the date stamp, and will crash or give unpredictable results when used with such files. Short, positive dated files which use the Absolute_verylong convention are fine, although this issue may also affect output from any very long, continuous run whose timestep numbers have become very large. Jeff says the number limit in conv.sh is hardcoded, and won’t be fixed any time soon. Workarounds are available, but also annoying.

Page last modified on August 16, 2011, at 11:01 AM by robin