Geomagnetic and Solar Dependency of MSTIDs Occurrence Rate: A Climatology Based on Airglow Observations From the Arecibo Observatory ROF

We employ in this work the first O(1D) 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. Plain Language Summary The medium scale traveling ionospheric disturbances (MSTIDs) are one of the most observed perturbations in the nighttime ionosphere in mid latitudes. Arguably, many aspects of their nature are still poorly understood. This paper focuses on a quantitative analysis of the MSTIDs observed at the Arecibo Observatory Remote Optical Facility located in Culebra, Puerto Rico, using airglow images of the red line emission (630.00 nm). We show the occurrence rate of the MSTIDs found at Remote Optical Facility and their dependency on solar and geomagnetic activities. We discuss our findings based on the relation between the MSTIDs and the behavior of the background thermospheric neutral winds over Puerto Rico. Key Points MSTIDs occurrence rate is modulated by solar activity, presenting periods of correlation and anticorrelation d