This question might be answered better with some knowledge of python(specifically scipy).

I'm using in situ ocean current data. For one of my analysis; i needed to used butterworth lowpass filter.

I wrote a code in python for the same. here is the snippet.

from scipy import signal

sos = signal.butter(1,1/6,'lowpass',output="sos",analog=False)

filtd = signal.sosfilt(sos, rawdata)

plt.plot(filtd,label="filtered data")

plt.plot(rawdata,label="raw data")

plt.legend()

In general, It's understandable that the magnitude has decreased significantly because, the high frequency variability has been removed.

It's possible for synthetic signal, where a spike of 100 with data points whose values are < 1 for the magnitude to disappear entirely. I'd like to know if this much decrease in magnitude is possible in terms of observed ocean current?

or by some chance my coding is wrong?