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Reply to Comment by E. R. Williams on “Twentieth century secular in the atmospheric gradient”
Author(s) -
Harrison Giles
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017381
Subject(s) - cosmic ray , cosmic cancer database , ionosphere , atmospheric electricity , environmental science , atmospheric sciences , physics , meteorology , astrophysics , geophysics , electric field , quantum mechanics
A substantial long‐term increase in solar activity, with an associated decrease in cosmic rays, is generally accepted to have occurred during the twentieth century [ Lockwood et al. , 1999]. Cosmic rays are known to modulate the global atmospheric electric circuit through changes in the ionospheric potential, and a decrease in the global atmospheric electric circuit is therefore expected in response to the solar activity increase [ Harrison , 2002]. Whether this has been observed in the long series [ Harrison , 2003] of surface Potential Gradient (PG) observations at Eskdalemuir, Scotland is questioned by Earle Williams because of: (1) the likely overestimate of stratospheric conductivity changes inferred from a cosmic ray proxy, (2) twentieth century air pollution changes in the UK, (3) the absolute magnitude and (4) absence of solar modulation in the PG at Eskdalemuir. These points are addressed in turn.