Factors, especially sunspot number, causing variations in surface air concentrations and depositions of ⁷Be in Osaka, Japan

Abstract

Abstracts. We found that increasing sunspot number caused a significant negative effect on monthly and yearly average air concentration and yearly deposition of 7Be.

The effects of large-scale atmospheric flows on berylium-7 activity concentration in surface air

“…The mean concentration of 7 Be concentration is 7.22 mBqm −3 for this period. The present 7 Be concentration values are roughly consistent with those reported byDibb (1989) (3.3-5.0 mBqm −3 in Maryland, USA),Dibb et al (1994Dibb et al ( , 2003a (1.5-4.5 mBqm −3 in Northwest Territories, Canada), andMegumi et al (2000) …”

“…Seasonal variations in the surface 7 Be concentration were reported by Feely et al (1989). In particular, the spring maximum was reported by Dibb (1989), Baskaran et al (1993) and Megumi et al (2000).…”

Seasonal and spatial variation of atmospheric 210Pb and 7Be deposition: features of the Japan Sea side of Japan

“…By analyzing the precipitation samples collected in Tsukuba (Pacific Ocean side of Japan) during 1986e1993, 40 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year of sampling Igarashi et al (1998) found values of 880e1780 Bq m ÿ2 . Megumi et al (2000) observed 7 Be depositions ranging from 970 to 1750 Bq m ÿ2 in Osaka from 1983 to 1997. More recently, Narazaki et al (2003) reported the annual 7 Be deposition throughout Japan (26 18#e43 05#N, 127 54#e141 27#E) from 1989 to 1995 was 1500 Bq m ÿ2 on average.…”

Production and behavior of beryllium 7 radionuclide in the upper atmosphere

“…Production of shortlived 7 Be (half life 53.3 days) in the atmosphere was studied by Lal and Peters (1967), Masarik and Beer (1999), Nagai et al (2000) and Land and Feichter (2003). The 7 Be production rate depends on the 11-year cycle of solar activity (Megumi et al, 2000;Gerasopoulos et al, 2003;Papastefanou and Ioannidou, 2004) because there is anticorrelation between the solar activity and GCR flux on the Earth. Further intense solar protons associated with a large solar event produce 7 Be in the upper atmosphere.…”