Calculates volumetrically weighted average hypolimnetic temperature using the supplied water temperature timeseries. If the lake is not stratified, an NA value is returned.
hypo.temperature(wtr, depths, bthA, bthD)a numeric vector of water temperature in degrees C.
a numeric vector corresponding to the depths (in m) of the wtr measurements
a numeric vector of cross sectional areas (m^2) corresponding to bthD depths
a numeric vector of depths (m) which correspond to areal measures in bthA