@BeginModule
@Name      = EcaCfd
@Title     = Consecutive frost days index per time period
@Section   = Climate indices
@Class     = Climate index
@Arguments = ifile ofile
@Operators = eca_cfd

@BeginDescription
Let @file{ifile} be a time series of the daily minimum temperature TN, then the largest number of
consecutive days where TN < 0 @celsius is counted. Note that TN have to be given in units of Kelvin.
A further output variable is the number of frost periods of more than @math{N} days.
The date information of a timestep in @file{ofile} is the date of the last contributing timestep in @file{ifile}.
@EndDescription
@EndModule


@BeginOperator_eca_cfd
@Title     = Consecutive frost days index per time period
@Parameter = [N]
@EndOperator


@BeginParameter
@Item = N
INTEGER  Minimum number of days exceeded (default: N = 5)
@EndParameter


@BeginExample
To get the largest number of consecutive frost days of a time
series of daily minimum temperatures use:
@BeginVerbatim
   cdo eca_cfd tnfile ofile
@EndVerbatim
@EndExample
