This article reviews atmospheric changes associated with 44 solar eclipses, beginning with the first quantitative results available, from 1834 (earlier qualitative, accounts also exist). Eclipse meteorology attracted relatively few publications until the total solar eclipse of 16 February 1980, with the 11 August 1999 eclipse producing the most papers. Eclipses passing over populated areas such as Europe, China and India now regularly attract scientific attention, whereas atmospheric measurements of eclipses at remote locations remain rare. Many measurements and models have been used to exploit the uniquely predictable solar forcing provided by an eclipse. In this paper we compile the available publications and review a sub-set of them chosen on the basis of importance and novelty. Beyond the obvious reduction in incoming solar radiation, atmospheric cooling from eclipses can induce dynamical changes. Observations and meteorological modelling provide evidence for the generation of a local eclipse circulation which may be the origin of the "eclipse wind". Gravity waves set up by the eclipse can, in principle, be detected as atmospheric pressure fluctuations, though theoretical predictions are limited, and many of the data are inconclusive. Eclipse events providing important early insights into the ionisation of the upper atmosphere are also briefly reviewed.

Atmospheric changes from solar eclipses

This article reviews atmospheric changes associated with 44 solar eclipses, beginning with the first quantitative results available, from 1834 (earlier qualitative accounts also exist). Eclipse meteorology attracted relatively few publications until the total solar eclipse of 16 February 1980, with the 11 August 1999 eclipse producing the most papers. Eclipses passing over populated areas such as Europe, China and India now regularly attract scientific attention, whereas atmospheric measurements of eclipses at remote locations remain rare. Many measurements and models have been used to exploit the uniquely predictable solar forcing provided by an eclipse. In this paper, we compile the available publications and review a subset of them chosen on the basis of importance and novelty. Beyond the obvious reduction in incoming solar radiation, atmospheric cooling from eclipses can induce dynamical changes. Observations and meteorological modelling provide evidence for the generation of a local eclipse circulation that may be the origin of the ‘eclipse wind’. Gravity waves set up by the eclipse can, in principle, be detected as atmospheric pressure fluctuations, though theoretical predictions are limited, and many of the data are inconclusive. Eclipse events providing important early insights into the ionization of the upper atmosphere are also briefly reviewed. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2015.0217

Atmospheric changes from solar eclipses.

Impact of the 15 January 2010 annular solar eclipse on the equatorial and low latitude ionosphere over the Indian region

[1] Temporal variation of secondary cosmic rays (SCR) flux was measured during the total lunar eclipse on 10 December 2011 and the subsequent full moon on 8 January 2012 from Mumbai (Geomagnetic latitude: 10.6°N), India. The measurements were done by using NaI (Tl) scintillation detector with energy threshold of 200 keV. The SCR flux shows approximately 8.1% enhancement during the lunar eclipse as compared to the average of pre- and post-eclipse periods. Weather parameters (temperature and relative humidity) were continuously monitored, and their correlations with temporal variation in SCR flux have been examined. The influences of geomagnetic field, interplanetary parameters, and tidal effect on SCR flux have been considered. Qualitative analysis of SCR flux variation indicates that local weather, interplanetary, and geomagnetic factors affecting SCR flux fail to explain the observed enhancement during the eclipse. Lunar tidal effect on magnetosphere and crust still remains a possible mechanism which needs to be investigated in detail. The enhancement during lunar eclipse and widely reported decrease during solar eclipses may unravel hitherto unnoticed factors modulating SCR flux.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2013JA019007

Confirmation of secondary cosmic ray flux enhancement during the total lunar eclipse of 10 December 2011

The dual frequency Global Positioning System (GPS) observation data from International GNSS Services (IGS) stations established at Bangalore (IISC) and Hyderabad (HYDE) are processed to estimate the change in ionospheric total electron content (TEC) in response to the annular solar eclipse of 15 January 2010. This event was unique since it took place during solar minimum. It was a geomagnetically quiet period and the eclipse phase coincided with the peak ionization time at the Indian equatorial and low latitudes. The path of the solar obscuration during the eclipse passed through the Indian Ocean, touching the southern part of India. The sudden collapse of the TEC curve at Bangalore and Hyderabad indicates the effect of of blocked solar radiation on decayed electron content in ionosphere over the region. The magnitude of the depletion in ionospheric TEC over both stations are compared with mean diurnal ionospheric TEC of five quietest days of the month to investigate the eclipse effect on electron density of ionosphere over the stations.

Anirudha Patankar

Papers

A study of secondary cosmic ray flux variation during the annular eclipse of 15 January 2010 at Rameswaram, India