#################
 Output metadata
#################

Output metadata contains at least the following variables:

-  lat
-  lat_bnds
-  lon_bnds
-  lon
-  time
-  time_bnds
-  index

******************************
 lat, lon, lat_bnds, lon_bnds
******************************

They are copied from source file with all their attributes.

********************
 time and time_bnds
********************

+----------------------+-----------------------+-----------------+------------------+
| Slice_mode           | *time*                | *time_bnds*     |                  |
+======================+=======================+=================+==================+
| ``year``             | YYYY-07-01            | YYYY-01-01      | (YYYY+1)-01-01   |
+----------------------+-----------------------+-----------------+------------------+
| ``month``            | YYYY-MM-16            | YYYY-MM-01      | YYYY-(MM+1)-01   |
+----------------------+-----------------------+-----------------+------------------+
| ``ONDJFM``           | YYYY-01-01            | YYYY-10-01      | (YYYY+1)-04-01   |
+----------------------+-----------------------+-----------------+------------------+
| ``AMJJAS``           | YYYY-07-01            | YYYY-04-01      | YYYY-10-01       |
+----------------------+-----------------------+-----------------+------------------+
| ``DJF``              | YYYY-01-16            | YYYY-12-01      | (YYYY+1)-03-01   |
+----------------------+-----------------------+-----------------+------------------+
| ``MAM``              | YYYY-04-16            | YYYY-03-01      | YYYY-06-01       |
+----------------------+-----------------------+-----------------+------------------+
| ``JJA``              | YYYY-07-16            | YYYY-06-01      | YYYY-09-01       |
+----------------------+-----------------------+-----------------+------------------+
| ``SON``              | YYYY-10-16            | YYYY-09-01      | YYYY-12-01       |
+----------------------+-----------------------+-----------------+------------------+

.. note::

   The second bound in time_bnds is excluded!

Example: annual time steps
==========================

.. code:: rest

   $ ncdump -v time indice_FD_year_1950-1955.nc -t

   time = "1950-07-01", "1951-07-01", "1952-07-01", "1953-07-01",
       "1954-07-01", "1955-07-01" ;

   $ ncdump -v time_bnds indice_FD_year_1950-1955.nc -t

   time_bnds =
       "1950-01-01 12", "1951-01-01 12",
       "1951-01-01 12", "1952-01-01 12",
       "1952-01-01 12", "1953-01-01 12",
       "1953-01-01 12", "1954-01-01 12",
       "1954-01-01 12", "1955-01-01 12",
       "1955-01-01 12", "1956-01-01 12" ;

Example: monthly time steps
===========================

.. code:: rest

   $ ncdump -v time indice_FD_month_1950-1955.nc -t

   time = "1950-01-16", "1950-02-16", "1950-03-16", "1950-04-16",
       "1950-05-16", "1950-06-16", "1950-07-16", "1950-08-16",
       "1950-05-16", "1950-06-16", "1950-07-16", "1950-08-16",
       [...]

   $ ncdump -v time_bnds indice_FD_month_1950-1955.nc -t

   time_bnds =
       "1950-01-01 12", "1950-02-01 12",
       "1950-02-01 12", "1950-03-01 12",
       "1950-03-01 12", "1950-04-01 12",
       "1950-04-01 12", "1950-05-01 12",
       [...]

Example: seasonal time steps
============================

.. code:: rest

   $ ncdump -v time indice_FD_DJF_1950-1955.nc -t

   time = "1951-01-16", "1952-01-16", "1953-01-16", "1954-01-16",
       "1955-01-16" ;

   $ ncdump -v time_bnds indice_FD_DJF_1950-1955.nc -t

   time_bnds =
       "1950-12-01 12", "1951-03-01 12",
       "1951-12-01 12", "1952-03-01 12",
       "1952-12-01 12", "1953-03-01 12",
       "1953-12-01 12", "1954-03-01 12",
       "1954-12-01 12", "1955-03-01 12" ;

.. code:: rest

   $ ncdump -v time indice_FD_SON_1950-1955.nc -t

   time = "1950-10-16", "1951-10-16", "1952-10-16", "1953-10-16",
       "1954-10-16", "1955-10-16" ;

   $ ncdump -v time_bnds indice_FD_SON_1950-1955.nc -t

   time_bnds =
       "1950-09-01 12", "1950-12-01 12",
       "1951-09-01 12", "1951-12-01 12",
       "1952-09-01 12", "1952-12-01 12",
       "1953-09-01 12", "1953-12-01 12",
       "1954-09-01 12", "1954-12-01 12",
       "1955-09-01 12", "1955-12-01 12" ;

*******
 index
*******

The *index* variable has the same name as index_name parameter (e.g.
"FD"). It has the following attributes:

   -  long_name
   -  units
   -  _FillValue
   -  missing_value
   -  ( grid_mapping )

Example:

.. code:: rest

   float FD(time, lat, lon) ;
           FD:_FillValue = 1.e+20f ;
           FD:long_name = "Frost days (minimum temperature < 0 degrees)" ;
           FD:units = "days" ;
           FD:missing_value = 1.e+20f ;
           FD:standard_name = "ECA_index" ;

.. note::

   The *_FillValue* and *missing_value* are the same as in source files.

*******************
 Global attributes
*******************

According to the CF convention, the output NetCDF file contains 6 main global attributes:
   -  title
   -  institution
   -  source
   -  history
   -  references
   -  comment

Example:

.. code:: rest

   // global attributes:
       :title = "ECA cold index FD" ;
       :institution = "Climate impact portal (https://climate4impact.eu)" ;
       :source =  ;
       :references = "ATBD of the ECA indices calculation (https://knmi-ecad-assets-prd.s3.amazonaws.com/documents/atbd.pdf)" ;
       :comment = " " ;
       :history = "2011-04-07T06:39:36Z CMOR rewrote data to comply with CF standards and CMIP5 requirements. \n",
                       "2014-04-01 12:16:03 Calculation of FD index (monthly time series) from 1950-1-1 to 1955-12-31." ;