diff --git a/doc/source/user_guide/ug_implementation.rst b/doc/source/user_guide/ug_implementation.rst index b24d96909..ab1d2fcc3 100644 --- a/doc/source/user_guide/ug_implementation.rst +++ b/doc/source/user_guide/ug_implementation.rst @@ -1192,33 +1192,35 @@ The history modules allow output at different frequencies. Five output frequencies (``1``, ``h``, ``d``, ``m``, ``y``) are available simultaneously during a run. The same variable can be output at different frequencies (say daily and monthly) via its namelist flag, `f\_` :math:`\left<{var}\right>`, which -is now a character string corresponding to ``histfreq`` or ‘x’ for none. -(Grid variable flags are still logicals, since they are written to all +is a character string corresponding to ``histfreq`` or ‘x’ for none. +(Grid variable flags are logicals, since they are written to all files, no matter what the frequency is.) If there are no namelist flags with a given ``histfreq`` value, or if an element of ``histfreq_n`` is 0, then no file will be written at that frequency. The output period can be -discerned from the filenames. All history streams will be either instantaneous -or averaged as specified by the ``hist_avg`` namelist setting and the frequency -will be relative to a reference date specified by ``histfreq_base``. Also, some +discerned from the filenames. Each history stream will be either instantaneous +or averaged as specified by the corresponding entry in the ``hist_avg`` namelist array, and the frequency +will be relative to a reference date specified by the corresponding entry in ``histfreq_base``. +More information about how the frequency is +computed is found in :ref:`timemanager`. +Also, some Earth Sytem Models require the history file time axis to be centered in the averaging interval. The flag ``hist_time_axis`` will allow the user to chose ``begin``, ``middle``, -or ``end`` for the time stamp. More information about how the frequency is -computed is found in :ref:`timemanager`. +or ``end`` for the time stamp. For example, in the namelist: :: - histfreq = ’1’, ’h’, ’d’, ’m’, ’y’ - histfreq_n = 1, 6, 0, 1, 1 - histfreq_base = 'zero' - hist_avg = .true.,.true.,.true.,.true.,.true. - f_hi = ’1’ - f_hs = ’h’ - f_Tsfc = ’d’ - f_aice = ’m’ - f_meltb = ’mh’ - f_iage = ’x’ + histfreq = '1', 'h', 'd', 'm', 'y' + histfreq_n = 1 , 6 , 0 , 1 , 1 + histfreq_base = 'zero','zero','zero','zero','zero' + hist_avg = .true.,.true.,.true.,.true.,.true. + f_hi = '1' + f_hs = 'h' + f_Tsfc = 'd' + f_aice = 'm' + f_meltb = 'mh' + f_iage = 'x' Here, ``hi`` will be written to a file on every timestep, ``hs`` will be written once every 6 hours, ``aice`` once a month, ``meltb`` once a month AND