On the presence of a volcanic stratospheric dust stratum over a polluted atmosphere: Mexico City

Abstract

Anomalous aerosol high extinction values have been detected from turbidity measurements made in Mexico City since November 1974 until March 1975. After substraction of the background turbidity values due to the " normal"' polluted haze of the city one obtains turbidity values that indicate a mean local reduction of atmospheric transparency of 2.6% Visual observations sustained with pictures of colorful twilight glows noticed about 35-40' after sunset are consistent with several earlier reports of Meinel and Meinel and Volz, between others, of the wide spread of the volcanic dust stratum originated from volcanic eruptions ocurred between the I 3 and 23 October 1974 at the Volcan de Fuego in Guatemala.