Geomagnetic and Solar Dependency of MSTIDs Occurrence Rate: A Climatology Based on Airglow Observations From the Arecibo Observatory ROF
Pedrina Terra, Fábio Vargas, C. G. M. Brum, E. S. Miller
Abstract
Abstract We employ in this work the first O( 1 D) 630.0‐nm airglow data set registered at the Remote Optical Facility (ROF) in Culebra, Puerto Rico, during the descending phase of the solar cycle #24. From 4 November 2015 to 26 September 2019, observations were carried out during 633 nights at ROF using a small all‐sky imager, while MSTID events were identified in 225 of 499 nights classified as clear. A quantitative analysis of these MSTIDs 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 data set and minimizes the cross contamination of individual modulators onto one another, avoiding bias in the results. Our findings include a primary peak of MSTIDs occurrence in the December solstice and a secondary peak in the June solstice. We observed a remarkable correlation in the occurrence rate of the MSTIDs with the geomagnetic activity. A notable modulation of the MSTIDs occurrence rate with the solar activity is also found, which includes periods of correlation and anticorrelation depending on the season. This modulation has an annual component that is ~33% and ~83% stronger than the semiannual and terannual components, respectively. We discuss these findings based on a previous study of the thermospheric neutral winds derived from 30 years of Fabry‐Perot interferometer observations at Arecibo Observatory. Our results, which are valid for low to moderate solar activity, point out circumstances that might explain differences in previous climatological studies of nighttime MSTIDs.