Past and upcoming important solar eclipses in the continental U.S.: Reviewing circumstances, studies on its environmental effects and future perspectives (speaker:Marcos Peñaloza-Murillo, University of the Andes, Venezuela)
Since the foundation of the United States of America in 1776 there have been several occurrences when a total or annular solar eclipse has taken place somewhere in its continental territory (including Alaska). During the period of 1776 – 2017, twenty-two total solar eclipses have occurred as well as fourteen annular solar eclipses. Some of them due to the extent of land touched by the Moon’s shadow may be dubbed as “Great American total solar eclipses”; the same can be applied when the penumbra of an annular solar eclipse has covered a large portion of the American continental territory: “Great American Annular Solar Eclipses”. Observers and scientists in different parts of the country have made measurements of air temperature, atmospheric pressure, solar radiation, relative humidity, wind speed and direction, cloudiness and other meteorological, thermodynamic and physical/chemical variables (shadow bands, sky brightness, etc.) to study the atmospheric response during these events. In this presentation, firstly, we make a general review of these eclipses with emphasis in the related scientific literature produced so far. Interestingly, we have found that the first meteorological measurements ever made in the U.S. during a total solar eclipse were taken in Boston through the eclipse that took place on November 30, 1834. The first observations ever made by the Williams College occurred on expeditions to study the 1925 and 1932 total solar eclipses in Connecticut and Maine (Fryeburg), respectively. These were reported in the scientific literature. Also, the eclipse of 1932 was used to estimate the atmospheric refraction via air temperature measurement at different height to study the effect that variable has on the deflection of starlight by the Sun’s gravitational field, etc. Secondly, we present the atmospheric measurements made by the Williams College expedition to Salem, Oregon, to observe the recent August 21st, 2017 Great American Total Solar Eclipse, which is at present under analysis based on our previous experiences with the Williams College expeditions to Zambia (Africa) to observe the first total solar eclipse of the century on June 22, 2001, to China to observe the longest total solar eclipse of the century on July 11, 2009, and to Norway (Svalbard archipelago) to observe under extreme conditions the total solar eclipse on March 20, 2015. Along with this, we also review the results obtained for this 2017 American eclipse by others already published in the specialized literature. Finally, with the two next solar eclipses ahead very closely, one annular on October 14, 2023, and the other, a Great American Total Solar Eclipse, on April 4, 2024, we assess the perspectives and expectations that these eclipses might cause for Earth sciences in the U.S., particularly for atmospheric physics and eclipse meteorology.