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.

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud.Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20th March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44N, 0.94W), Lerwick (60.15N, 1.13W) and Reykjavik (64.13N, 21.90W), straddling the path of the eclipse.The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming the sensing surface becomes normal to the solar beam direction at a maximum swing. Both approaches, essentially independent,give values that agree with theoretical expectations for the eclipse-induced radiation changes.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2015.0221

Coordinated weather balloon solar radiation measurements during a solar eclipse.

Atmospheric response to the 20 March 2015 solar eclipse along the whole aerosol column by lidar measurements

An experiment has been conducted to understand the I I Aug. I 999 solar ec lipse induced changes in the aerosol extinction coeffic ient in the troposphere and the lower stratosphere using the multiwavclength Iidar sys tem des igned and developed in-house at a tropical stati on Trivandrum (8° 33'N, 77° E) . Results of the measure ments reveal an increase in aerosol extincti on coeffic ient in the troposphere and a decrease in the lower stratosphere compared to contro l day. Six high altitude balloon ascents with I 680 MHz radiosonde were conducted from Thumba to study the ec lipse induced variations in winds and temperature of the lower atmosphere. The study clearly reveals the cooli ng of the ent ire tropospheric layers with maximum of 5° C occurring be low 15 km altitude . The changes in the temperature and the relative hu midity during the ec lipse are the key factors contributed for the observed aerosol ext inction coefficient.

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Solar eclipse induced changes in aerosol extinction profiles: A case study of 11 Aug. 1999 solar eclipse using lidar at a tropical station Trivandrum, India

D Ramakrishna Rao

Papers

Solar eclipse induced changes in aerosol extinction profiles: A case study of 11 Aug. 1999 solar eclipse using lidar at a tropical station Trivandrum, India