I am trying to connect the near coastal tidal signal ( point A ) to three points along the long border of the model ( BCD points ). I want to possibly have a relationship between the BCD , through which we can convert a prediction A in BC and D . I am currently doing one phase shift, an amplitude ration for levels above zero, an amplitude ration for levels below zero, and a mid-level shift.
This creates a kink in the tidal signal at the peak of ebb and Peak flood and leads to a model with prediction of recoil currents. I was wondering if anyone knows of more complex relationships for this kind of transformation?
One thing I would like to catch is the difference in the phase shift between high and low water (for example, the ratio of the period of positive periods to the period of negatives may differ for different points).
An example algorithm for the current process.
A = vector (size n x 1 ) units meters
time_A = vector (size n x 1 )
ph_B = phase shift for AvsB.
pos_amp_B = positive amplitude ration.
neg_amp_B = negative amplitude ration.
B_mean = long term mean of B.
A_mean = long term mean of A.
for i = 1:n
a = A(i) - A_mean
if a > 0
B(i) = a*pos_amp_B
else
B(i) = a*neg_amp_B
end
time_B(i) = time_A(i) = ph_B
B(i) = B(i) + B_mean
end
BTW: relationship is based on about 6 months of data.
EDIT 1: Well, first, just think of two sinusoidal signals (i.e., Amplitude, phase shift), but not regular, so for example, the period is 12.5 hours, but the slopes and periods of the positive half and negative half not all are the same. You do not need any contextual knowledge. I'm just looking for a conversion algorithm.
2:
fft (fft (12,5 ()), , ). - A. .
![Water Level [m] timeseries (top) and fft analysis (bottom)](https://fooobar.com/undefined)