Atmospheric interactions at northern high latitudes from weekly Be-isotopes in surface air

We present weekly Be-7 (from 1972 to 1995), and weekly/seasonal Be-10 (for 1994) data in surface air from ground level stations in Sweden with a coverage of most of the northern high latitudes (56 degrees -68 degrees N). Our Be data are regionally representative and reveal seasonal variation and coupling with tropospheric air mass from middle-low latitudes. The Be data also suggests a few percent, and sometimes episodic, incursion of stratospheric air mass. Frequent precipitation depletes the Be isotopes in the air, but cyclone events contribute to enrichments. A strong coherence between the Be-7 record and short-term (monthly-seasonal) change in solar activity is observed which introduces a new mechanism for driving the amplitude of seasonal variation. (C) 2001 Elsevier Science Ltd. All rights reserved.