SMILES observations of mesospheric ozone during the solar eclipse

Abstract

The Superconducting Submillimeter‐Wave Limb‐Emission Sounder (SMILES) successfully observed vertical distributions of ozone (O3) concentration in the middle atmosphere during the annular solar eclipse that occurred on 15 January 2010. In the mesosphere, where the photochemical lifetime of O3 is relatively short (approximately 100 s), altitude‐dependent changes in O3 concentration under reduced solar radiation and their temporal variations were clearly observed as a function of the eclipse obscuration. This study reports the vertical distributions of mesospheric O3 during a solar eclipse event and analyzes theoretically the eclipse‐induced changes. We show that simple analytical expressions for O3 concentration, which assume that O3 and O are in a photochemically steady state, can be used to describe the O3 concentration under reduced solar radiation. The SMILES data obtained during the eclipse provide a unique opportunity to test our current understanding of mesospheric O3 photochemistry.

Anomalous variations of VLF sub-ionospheric signal and Mesospheric Ozone prior to 2015 Gorkha Nepal Earthquake

“…The precipitation of high energetic particles could probably alter the mesospheric ozone concentration thereby leading to modification in VLF amplitudes/TT/electron density prior to earthquakes 36 , 37 . However, positive/negative anomalies prior/during the EQ of mesospheric ozone (corresponding VLF amplitude/TT/electron density) as evidenced in the present report (Figs 2 – 4 ) can be interpreted considering the relatively shorter life time of mesospheric ozone (few secs to less than an hour) 28 , 38 . In this context, Lithosphere-Atmosphere-Ionospheric Coupling (LAIC) model provides a better understanding of the physical processes involved in understanding the short-term variations in surface, lower atmospheric and ionospheric pre-seismic signatures before the major earthquakes which can derive from the observed anomalies in different atmospheric/ionospheric parameters within the earthquake preparation process 36 , 37 .…”

“…Mesospheric ozone percentage of variation estimated a day prior to EQ1 (EQ2) i.e., April 24, 2015 (May 11, 2015) is of the order of 30–40% (20–30%) in the altitude region (55–75 km) where statistically significant variation is clearly observed. Few reports in the past tried to understand mesospheric ozone variations with few event-based studies of geomagnetic storm and solar eclipse etc 26 – 28 and evidenced significant discrepancies (upto even 30%) in 70–80 km altitude regions. However, the variation of mesospheric ozone is complicated in lower/upper altitudes where ion chemistry alone is sufficient/not sufficient to explain the observed discrepancies.…”

Ground-Based Microwave Measurements of Mesospheric Ozone Variations over Moscow Region during the Solar Eclipses of 20 March 2015 and 25 October 2022

“…The most interesting and detailed results were reported in [9], where mesospheric ozone was observed during the solar eclipse of 15 January 2010 at frequencies of about 625 GHz from aboard the International Space Station. It was found in [9] that changes in the ozone mixing ratio (OMR) profiles at altitudes of 58-70 km in dependence on the Sun's obscuration during the eclipse were in good agreement with predictions of the comprehensive work on ozone chemistry in the mesosphere and lower thermosphere (MLT region, altitudes A = 50-100 km) [2]. Other observations [5][6][7][8] were not as complete and precise as [9], and their data were not robustly analyzed.…”

“…Up to now, only a few observations of mesospheric ozone during solar eclipses have been conducted using rockets [5], in near-IR [6], and at millimeter and submillimeter waves [7][8][9]. The most interesting and detailed results were reported in [9], where mesospheric ozone was observed during the solar eclipse of 15 January 2010 at frequencies of about 625 GHz from aboard the International Space Station.…”

“…Up to now, only a few observations of mesospheric ozone during solar eclipses have been conducted using rockets [5], in near-IR [6], and at millimeter and submillimeter waves [7][8][9]. The most interesting and detailed results were reported in [9], where mesospheric ozone was observed during the solar eclipse of 15 January 2010 at frequencies of about 625 GHz from aboard the International Space Station. It was found in [9] that changes in the ozone mixing ratio (OMR) profiles at altitudes of 58-70 km in dependence on the Sun's obscuration during the eclipse were in good agreement with predictions of the comprehensive work on ozone chemistry in the mesosphere and lower thermosphere (MLT region, altitudes A = 50-100 km) [2].…”