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５巻１号 （2024年4月） Volume 5, Number 1 (April 2024) |
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Paper: Decadal (2011–2020) stratospheric aerosol variability observed by lidar over Saga, Japan Osamu Uchino, Tetsu Sakai, Isamu Morino, Tomohiro Nagai, Hiroshi Okumura, Yoshitaka Jin, Atsushi Ugajin, Tomoaki Nishizawa, Atsushi Shimizu, Tsuneo Matsunaga, and Kohei Arai pp. 4-12 |
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Abstract Lidar observations at the wavelength of 532 nm during 2011‒2020 in Saga, Japan, revealed that strato- spheric aerosols increased after the eruptions of Nabro volcano in Eritrea on 12 June 2011 and Raikoke volcano in the central Kuril Islands on 22 June 2019. Maximum values of the backscattering ratio and the integrated backscattering coefficient of stratospheric aerosols from tropopause altitude to 33 km after the Nabro eruption were 3.70 at 18.22 km on 23 June 2011 and 3.65×10-4 sr-1 on 25 July 2011, respectively; those after the Raikoke eruption were 1.89 at 17.47 km on 8 August 2019 and 3.01×10-4 sr-1 on 1 November 2019, respectively. Assuming a lidar ratio of 50 sr at 532 nm, the maximum strato- spheric aerosol optical depth over Saga during the ten-year period from 2011 to 2020 was estimated to be 0.018 on 25 July 2011. Stratospheric smoke particles from the Canadian forest fires in August 2017 were also detected. The degree of depolarization of smoke particles was about 0.1‒0.18, and this value persisted for a long period of time, from 31 August 2017 to 22 February 22, 2018. These lidar data are useful for investigat- ing the effects of stratospheric aerosols on climate and the ozone layer. |
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Key Words: Lidar, Stratospheric Aerosol, Volcanic eruption, Smoke |