- interannual_variation(series, normalize=False)#
Interannual variation after [martens_2013].
- 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!
Martens, K., van Camp, M., van Damme, D., & Walraevens, K. (2013). Groundwater dynamics converted to a groundwater classification as a tool for nature development programs in the dunes. Journal of Hydrology, 499, 236–246.