A New Approach for Understanding the Occurrence Rate of MSTIDs in the Caribbean Nighttime Ionosphere

Space & Atmospheric Sciences


Atmospheric  

New results from the AO Remote Optical Facility (ROF) have shown that certain wavelike perturbations in the Earth’s ionosphere are highly dependent on season in a variety of ways. For the first time, these perturbations – known as Medium Scale Traveling Ionospheric Disturbances (MSTIDs) - were conclusively shown to be modulated by the geomagnetic and solar activities.

Dr. Pedrina Terra dos Santos, AO scientist and lead author of the study, explained, “Our investigation used a simple and original statistical methodology that maximized the unique features of the dataset according to the parameters that we investigated”. Specifically, the work focused on the quantitative behavior of the MSTIDs to find which factors contribute most to the occurrence of these perturbations in the Caribbean nighttime ionosphere.

The team of researchers collected data using a low-cost, small all-sky imager on 633 nights over the course of 4 years, between November 4, 2015 - September 26, 2019. This was the first O(1D) 630.0-nm airglow dataset registered at the ROF, which is located on the small island of Culebra, off the Eastern coast of the main island of Puerto Rico.

Using this large dataset, the scientists found a remarkable correlation in the occurrence rate of the MSTIDs with the geomagnetic activity. In addition, a notable modulation of this occurrence rate with the solar activity was also found, which includes periods of correlation and anti-correlation depending on the season.

“This work suggests that a critical factor for the occurrence rate of MSTIDs is the background thermospheric neutral wind behavior over Puerto Rico, which controls the instability that may or may not be favorable for the occurrence rate of the MSTID phenomena,” - Dr. Pedrina Terra Research Scientist at Arecibo Observatory

“This work suggests that a critical factor for the occurrence rate of MSTIDs is the background thermospheric neutral wind behavior over Puerto Rico, which controls the instability that may or may not be favorable for the occurrence rate of the MSTID phenomena,” Dr. Terra summarized. She added that this conclusion is also supported by a previous study published by AO scientist Dr. Christiano Brum.

The somewhat controversial results were published in the Journal of Geophysical Research - Space Sciences this month. To date, this manuscript is also the “most popular” pre-print in the Earth and Space Science Open Archive (ESSOAr): Atmospheric Sciences.


From the top to the bottom panels: Occurrence rate of MSTIDs registered at the Remote Optical Facility in Culebra; MSTIDs ​occurrence r​ ate by the decimetric solar flux as a function of day of the year (DOY), and; the responses of the MSTIDs ​occurrence ​rate to the variation on the geomagnetic activity for December Solstice, Equinoxes and June Solstice (from left to right panel).

Dr. Terra and collaborators are working on further studies of MSTIDs’ qualitative behavior and modeling. They are also looking for clues to better understand the Earth’s vertical atmospheric coupling during the approach of extreme weather events, which was motivated by some results of their study. A deeper look at the MSTIDs might provide some insight on the formation or frequency of hurricanes, for example. The scientists observed that the occurrence rate of the MSTIDs is suppressed during the peak of the Atlantic hurricane season, which agrees with data from GNSS receivers in Puerto Rico. “But,” Dr. Terra expressed, “we do not know yet why and how this reduction happens”.


Article written by Dr. Tracy Becker - AO Collaborator / SwRI Research Scientist Contact: tbecker@swri.edu

Arecibo Media Contact
Ricardo Correa
Communications Director Arecibo Observatory
787-878-2612 ext. 615
rcorrea@naic.edu

Technical Contact
Dr. Pedrina Terra
Arecibo Observatory
pterra@naic.edu

Keywords: arecibo, observatory, culebra, optics, santos, pedrina, puerto rico