We present weekly 7Be (from 1972 to 1995), and weekly/seasonal 10Be (for 1994) data in surface air from ground level stations in Sweden with a coverage of most of the northern high latitudes (56°-68°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 7Be record and short-term (monthly-seasonal) change in solar activity is observed which introduces a new mechanism for driving the amplitude of seasonal variation. Copyright (C) 2001 Elsevier Science Ltd.
- Solar activity
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