Portal de Periódicos da CAPES

Decadal variations of atmospheric 7Be and 10Be concentrations between 1998 and 2014 in Japan

2019; Elsevier BV; Volume: 455; Linguagem: Inglês

10.1016/j.nimb.2018.12.029

1872-9584

Takeyasu Yamagata, Hisao Nagai, Hiroyuki Matsuzaki, Yukinori Narasaki,

Atmospheric Ozone and Climate

Atmospheric concentrations of 7Be and 10Be were investigated in Dazaifu, Fukuoka (1998–2001) and Tokyo (2002–2014) from 1998 to 2014. The seasonal variations were roughly the same for each year, with high 7Be and 10Be concentrations and high 10Be/7Be isotopic ratios caused by strong stratosphere-troposphere exchange (STE) from February to June, and fluctuating 7Be and 10Be concentrations and constant 10Be/7Be ratios caused by vertical convection in the troposphere from July to December. Using a three-box model, the residence time of the stratosphere, the troposphere, and the boundary layer were estimated to be 2 years, 55 days, and 3 days, respectively, and the mass flux observed during the STE season was estimated to be six times higher than the mass flux observed during the vertical convection season. The amplitude of solar modulation was also found to be three times larger than the amplitude of relative cosmic ray intensity at the Earth's surface.