Properties and decay of stratospheric aerosols in the Arctic following the 1991 eruptions of Mount Pinatubo

• Published in: Geophysical research letters Vol. 20; no. 21; pp. 2359 - 2362
• Main Authors: Stone, Robert S., Key, Jeffrey R., Dutton, Ellsworth G.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Blackwell Publishing Ltd 05.11.1993; American Geophysical Union
• Subjects: AEROSOLS; Aircraft; Algorithms; Atmospheric composition. Chemical and photochemical reactions; COLLOIDS; CRYOSPHERE; Decay; DISPERSIONS; EARTH ATMOSPHERE; Earth, ocean, space; ECOLOGICAL CONCENTRATION; ENVIRONMENTAL SCIENCES; ERUPTION; Estimates; Exact sciences and technology; External geophysics; FLUIDS; GASES; Geophysics; LIFETIME; Meteorology And Climatology; OPACITY; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; Physics of the high neutral atmosphere; POLAR REGIONS; SOLS 540120 > Environment, Atmospheric > Chemicals Monitoring & Transport > (1990-); STRATOSPHERE; VOLCANIC GASES; Asia; Philippine Islands; Arctic Region; Arctic; Particle size; Volcanic eruption; Optical properties; Aircraft observation; Stratosphere; Upper atmosphere; Optical thickness; Opacity; Dimension spectrum; Physical properties; Stratospheric aerosol
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/93GL02684

Sunphotometer observations made from an aircraft several months after the June 1991 eruptions of Mount Pinatubo are used to quantify the spectral opacity of the Arctic stratosphere. Ancillary surface-based measurements are presented in support of the aircraft data that show large increases in stratospheric optical depth attributed to the presence of volcanic aerosols. Visible optical depths greater than 0.2 were observed during flight segments flown above the tropopause. An inversion algorithm and the optical depth data are used to infer effective aerosol size distributions. The distributions tend to be bimodal, having a large-partical mode radius of about 0.50 micron and a small-particle mode of higher concentration with radii less than 0.18 micron. Surface measurements made during spring 1992 and 1993 are also used to estimate a time constant (e-folding time) of about 13.5 months assuming that the Arctic stratosphere's opacity decays exponentially; this estimate is larger than decay times observed following other major volcanic eruptions. Our results suggest that any climate perturbations in the Arctic caused by eruptions of Pinatubo may be significant and will very likely persist longer than any volcanically-induced changes observed there during the past century.