On recent (2008–2012) stratospheric aerosols observed by lidar over Japan

摘要

An increase in stratospheric aerosols caused by the volcanic eruption of Mt.Nabro (13.37° N, 41.70° E) on 12 June 2011 was detectedby lidar at Tsukuba (36.05° N, 140.13° E) and Saga(33.24° N, 130.29° E) in Japan. The maximumbackscattering ratios at a wavelength of 532 nm were 2.0 at 17.0 km on 10July 2011 at Tsukuba and 3.6 at 18.2 km on 23 June 2011 at Saga. The maximumintegrated backscattering coefficients (IBCs) at 532 nm above the first tropopauseheight were 4.18×10−4 sr?1 on 11 February 2012 atTsukuba and 4.19×10−4 sr?1 on 23 June 2011 at Saga,respectively.A time series of lidar observational results at Tsukuba have also beenreported from January 2008 through May 2012. Increases in stratosphericaerosols were observed after the volcanic eruptions of Mt. Kasatochi(52.18° N, 175.51° E) in August 2008 and Mt. SarychevPeak (48.09° N, 153.20° E) in June 2009. The yearlyaveraged IBCs at Tsukuba were 2.54×10−4 sr?1,2.48×10−4 sr?1, 2.45×10−4 sr?1,and 2.20×10−4 sr?1 for 2008, 2009, 2010, and 2011,respectively. These values were about twice the IBC background level(1.21×10−4 sr?1) from 1997 to 2001 at Tsukuba. We brieflydiscuss the influence of the increased aerosols on climate and theimplications for analysis of satellite data.