A strong link between variations in sea-ice extent and global atmospheric pressure?

Abstract

Abstract. Abstract. This paper reports spectral analyses, using Singular Spectral Analysis, of variations of the Arctic and Antarctic sea-ice extents (SI), and of the atmospheric surface pressure (AP) in both hemispheres (NH and SH). The ice-extents are dominated by a quasi-linear trend over the 42 yr period when data are available (1978–2020) and an annual component. Taken together, these two components represent more than 98 % of the signal variance. Both ice-extent series share the same 5 set of harmonics of the annual component (1/2, 1/3, 1/4 and 1/5 yr). The multi-decadal trends of sea-ice extent in the Arctic and Antarctic are of opposite sign. The series of harmonics of 1 year are consequences of the Earth’s revolution about the Sun. The components with period longer than a year form a set of even harmonics of the Schwabe cycle. The pressure series also exhibits the four harmonics of 1 year, that is not found in many series previously analysed in the same way. This could suggest a connection between variations in pressure and sea-ice extent. Geographical pressure structures (SSA trends) are stable on a 10 decadal to centennial time scale and exhibit a three-fold symmetry in the NH. In the SH that order-3 symmetry is altered by the Ross-Weddell “dipole” pressure anomaly. This anomaly is seen in maps of correlations of variations in sea-ice extent with atmospheric pressure, surface temperature and winds. It fits topographic forcing. There is phase opposition between the annual components of SI and AP in the SH, and the same decreasing phase lag from −30 to −60 days over 42 years for the four harmonic components of SHSI and SHAP. The (negative) sign of the trend of pressure and (positive) sign of the trend of temperature 15 beg for an explanation. The relative change in pressure over the past 50 years is two orders of magnitude smaller than that of warming. This relatively strong warming would be expected to have a larger effect on pressure. The ratio of relative changes of sea-ice extent vs pressure is 400 for the NH and 17 for the SH. The SSA components reported in this paper should help in understanding the mechanisms that govern changes in sea-ice extent: these changes reflect forcings related to the Earth’s revolution about the Sun on the shorter period side, and on the longer period side to the Sun and planets (Jupiter). Advanced 20 explanation of the physics underling these observations may need advances in solving the generalized Navier-Stokes equations, which is very difficult in the spherical case.

On the annual and semi-annual components of variations in extent of Arctic and Antarctic sea-ice

“…Laplace assumes that all masses on and in Earth are set into motion by astronomical forces. As already shown in a previous work (see Le Mouël et al, (2021b), figure 03), the trends observed in the time series are quasi linear, decreasing for NHSI (by 58.300 km 2 /yr) and increasing for SHSI (by 15.400 km 2 /yr). The amplitude of annual variations in the Antarctic is double that in the Arctic, they are in phase opposition and modulated, with a flat trend for SHSI, a decreasing trend for NHSI and a sub-decadal modulation of the envelopes.…”

“…This is already known regarding the variations of the sea-ice dipole in Antarctica (cf. Holland et al (2017); Bertler et al (2018); Le Mouël et al (2021b) and the variations of the trends of global atmospheric pressure (cf. (Lopes et al 2022b)).…”

On the Annual and Semi-Annual Components of Variations in Extent of Arctic and Antarctic Sea-Ice

“…This is already known regarding the variations of the sea ice dipole in Antarctica (cf. [69][70][71]) and variations in the trends of global atmospheric pressure (cf. [6]).…”

On the external forcing of global eruptive activity in the past 300 years

“…Similarly to short-term timescales and tidal periodicities, these multi-annual to centennial variations are present in other geophysical parameters. Most of them record both tidal and solar periodicities, as illustrated by the magnetic field (e.g., Bartels, 1932;Le Mouël, 1984;Courtillot and Le Mouël, 1988;Jault, 1990;Le Mouël et al, 2019), polar motion (Lopes et al, 2017;Lopes et al, 2021a;Lopes et al, 2022a), sea level observed from local and global data (e.g., Chambers et al, 2012;Wahl and Chambers, 2015;Le Mouël et al, 2021a;Courtillot et al, 2022a), global surface air temperatures (e.g., Courtillot et al, 2013;Le Mouël et al, 2020b;Scafetta, 2021), and more generally, climate (e.g., Wood and Lovett, 1974;Schlesinger and Ramankutty, 1994;Scafetta, 2010;Courtillot et al, 2013;Scafetta, 2016;Le Mouël et al, 2019c;Le Mouël et al, 2021b). Moreover, these links also seem to exist 1) on much longer timescales of millennia, governed by astronomical configurations and impacting climate and sedimentation (e.g., Milanković, 1920;Kutterolf et al, 2013;Coussens et al, 2016;Kutterolf et al, 2019;Lopes et al, 2021b;Satow et al, 2021); and 2) also for earthquakes, as suggested by numerous studies (e.g., Tamrazyan, 1968;Mazzarella and Palumbo, 1988;Marchitelli et al, 2020).…”