source: XIOS/trunk/src/date/calendar_type.hpp @ 550

Last change on this file since 550 was 550, checked in by rlacroix, 6 years ago

Add a new user defined calendar type.

A new calendar type "user_defined" is now available. This allows the users to create a custom calendar that we can configured to be suitable for planets other than the Earth.

An user defined calendar is always defined by two mandatory attributes:

  • day_length: the duration of a day, in seconds
  • and either:
    • month_length: an array containing the duration of each month, in days (the number of elements in the array is the number of months in a year)
    • or year_length: the duration of a year, in seconds (in that case, the calendar does not have months).

If the calendar has months (i.e. month_length attribute is set) and only in that case, it is possible to define leap years in order to compensate for the duration of an astronomical year not being a multiple of the day length. The leap years are defined by two mandatory attributes:

  • leap_year_month: the month to which the extra day will be added in case of leap year, expressed as an integer number in the range [1, numberOfMonths]
  • and leap_year_drift: the fraction of a day representing the yearly drift between the calendar year and the astronomical year, expressed as a real number in the range [0, 1).

Optionally, one can define the leap_year_drift_offset attribute to set the original drift at the beginning of the time origin's year, again expressed as a real number in the range [0, 1). If leap_year_drift_offset + leap_year_drift is greater or equal to 1, then the first year will be a leap year.

For example, the following configuration creates a Gregorian-like calendar:

<calendar type="user_defined" start_date="2012-03-01 15:00:00" time_origin="2012-02-28 15:00:00 + 1d" day_length="86400" month_lengths="(1, 12) [31 28 31 30 31 30 31 31 30 31 30 31]" leap_year_month="2" leap_year_drift="0.25" leap_year_drift_offset="0.75" />

Note that dates attributes must be written differently in the configuration file when using an user defined calendar without months:

  • if the year length is greater than the day length, the input format is year-day hh:min:sec instead of year-month-day hh:min:sec
  • if the day length is greater or equal to the year length, the input format is year hh:min:sec.

In all cases, it is still possible to use the date + duration notation to build a date (with both the date and duration parts being optional).

The Fortran interface has been updated accordingly so that xios_define_calendar can accept the new attributes necessary to define custom calendars.

  • Property copyright set to
    Software name : XIOS (Xml I/O Server)
    Creation date : January 2009
    Licence : CeCCIL version2
    see license file in root directory : Licence_CeCILL_V2-en.txt
    Holder : CEA/LSCE (Laboratoire des Sciences du CLimat et de l'Environnement)
    CNRS/IPSL (Institut Pierre Simon Laplace)
    Project Manager : Yann Meurdesoif
File size: 239 bytes
1#ifndef __XMLIO_calendar_type__
2#define __XMLIO_calendar_type__
4#include "allleap.hpp"
5#include "d360.hpp"
6#include "gregorian.hpp"
7#include "julian.hpp"
8#include "noleap.hpp"
9#include "user_defined.hpp"
11#endif //__XMLIO_calendar_type__
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