interannual_variation(series, normalize=True)[source]#

Interannual variation after Martens et al. [2013].

  • series (pandas.Series) – Pandas Series with DatetimeIndex and head values.

  • normalize (bool, optional) – normalize the time series to values between zero and one.

Return type



The average between the range in annually averaged 3 highest monthly groundwater heads and the range in annually averaged 3 lowest monthly groundwater heads.

Inter-yearly variation of high and low water table (y):

y = ((max_HW - min_HW) + (max_LW - min_LW)) / 2

Warning: In this formulating the water table is references to a certain datum and positive, not as depth below the surface!