Geomagnetic and Solar dependency of MSTIDs occurrence rate: A
climatology based on airglow observations from the Arecibo Observatory
Remote Optical Facility (ROF)
Abstract
We employ in this work the first airglow dataset registered at the
Remote Optical Facility (ROF) in Culebra, Puerto Rico, during the
descending phase of the solar cycle #24. From November 4, 2015, to
September 26, 2019, observations were carried out during 633 nights at
ROF using a small all-sky imager, while events were identified in 225 of
499 nights classified as clear. A quantitative analysis of these and
their dependency by geophysical parameters (solar and geomagnetic
activities) are the main focus of this study. We introduce an original
statistical methodology that examines the unique features of the dataset
and minimizes the cross-contamination of individual modulators onto one
another, avoiding bias in the results. Our findings include a primary
peak of occurrence in the December solstice and a secondary peak in the
June solstice. We observed a remarkable correlation in the occurrence
rate of the with the geomagnetic activity. A notable modulation of the
occurrence rate with the solar activity is also found, which includes
periods of correlation and anti-correlation depending on the season.
This modulation has an annual component that is ~33%
and ~83% stronger than the semi-annual and terannual
components, respectively. We discuss these findings based on the
behavior of the thermospheric neutral winds derived from 30 years of
Fabry-Perot interferometer observations. Our results, which are valid
for low to moderate solar activity, point out circumstances that might
explain differences in previous climatological studies of nighttime