@BeginModule
@NewPage
@Name      = Zonstat
@Title     = Zonal statistical values
@Section   = Statistical values
@Class     = Statistic
@Arguments = ifile ofile
@Operators = zonmin zonmax zonsum zonmean zonavg zonstd zonstd1 zonvar zonvar1 zonpctl

@BeginDescription
This module computes zonal statistical values of the input fields.
According to the chosen operator the zonal minimum, maximum, sum, average,
variance, standard deviation or a certain percentile is written to @file{ofile}.
This operator requires all variables on the same regular lon/lat grid.
@EndDescription
@EndModule


@BeginOperator_zonmin
@Title     = Zonal minimum

@BeginDescription
For every latitude the minimum over all longitudes is computed.
@EndDescription
@EndOperator


@BeginOperator_zonmax
@Title     = Zonal maximum

@BeginDescription
For every latitude the maximum over all longitudes is computed.
@EndDescription
@EndOperator


@BeginOperator_zonsum
@Title     = Zonal sum

@BeginDescription
For every latitude the sum over all longitudes is computed.
@EndDescription
@EndOperator


@BeginOperator_zonmean
@Title     = Zonal mean

@BeginDescription
For every latitude the mean over all longitudes is computed.
@EndDescription
@EndOperator


@BeginOperator_zonavg
@Title     = Zonal average

@BeginDescription
For every latitude the average over all longitudes is computed.
@EndDescription
@EndOperator


@BeginOperator_zonvar
@Title     = Zonal variance

@BeginDescription
For every latitude the variance over all longitudes is computed. Divisor is n.
@EndDescription
@EndOperator


@BeginOperator_zonvar1
@Title     = Zonal variance

@BeginDescription
For every latitude the variance over all longitudes is computed. Divisor is (n-1).
@EndDescription
@EndOperator


@BeginOperator_zonstd
@Title     = Zonal standard deviation

@BeginDescription
For every latitude the standard deviation over all longitudes is computed. Divisor is n.
@EndDescription
@EndOperator


@BeginOperator_zonstd1
@Title     = Zonal standard deviation

@BeginDescription
For every latitude the standard deviation over all longitudes is computed. Divisor is (n-1). 
@EndDescription
@EndOperator


@BeginOperator_zonpctl
@Title     = Zonal percentiles
@Parameter = p

@BeginDescription
For every latitude the pth percentile over all longitudes is computed.
@EndDescription
@EndOperator


@BeginParameter
@Item = p
FLOAT  Percentile number in {0, ..., 100}
@EndParameter


@BeginExample
To compute the zonal mean of all input fields use:
@BeginVerbatim
   cdo zonmean ifile ofile
@EndVerbatim

To compute the 50th meridional percentile (median) of all input fields use:
@BeginVerbatim
   cdo zonpctl,50 ifile ofile
@EndVerbatim
@EndExample
