The ALPAQUITA prototype, part of the ALPACA experiment at Chacaltaya, Bolivia, utilizes 97
surface detectors to monitor cosmic ray fluxes in multiple counting rate modes, corresponding to
different median rigidities. To enable precise studies of transient cosmic ray phenomena such as
the Forbush Decrease, it is essential to correct detector data for environmental effects, notably
atmospheric pressure and temperature variations.
In this work, we present the correction methodology applied to ALPAQUITA’s counting rate data
using on-site meteorological measurements. Especially, we discuss the implementation of Fast
Fourier Transformation (FFT) techniques to refine the correction, finally obtaining less than half
of the magnitude of fluctuations in the short term before correction.

