A possible relationship between the Arctic Oscillation Index and atmosphere-triggered interannual long-wavelength gravitational variations( ∗ )

Summary. — A host of geophysical processes contribute to temporal variations in the low-degree zonal harmonics of the Earth’s gravity field. The present paper focuses on atmosphere-based mass redistributions using global surface pressure data from the NOAA Climate Diagnostics Center for the period 1980-2002. We computed atmosphere-triggered temporal variations of the Earth’s low-degree zonal gravitational coefficients Jl (l = 2 : 4). Such atmosphere-triggered ∆Jl(t )a re compared with the Arctic Oscillation Index (AOI) and with the observed ∆Jl(t) computed by the Italian Space Agency (ASI) so as to investigate a possible coupling. We show that there is a significant agreement between the AOI and atmosphere-triggered ∆Jl(t), as well as a particularly interesting correlation between the winter ∆Jl(t) series and the AOI active season series.