scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
Influence of solar variability on rotation and climate of the Earth
Kuznetsova Tamara
IZMIRAN, Russian Academy of Sciences, 142190 Moscow region, Troitsk, Russia
The paper presents results of our study of connection between changes of solar activity
(sunspot numbers W), rotation rate (w) and global temperature (Tgl) to understand their
connection on different time scales in the past, present and close future. We use W for the
period 1700-2005, proxy data of north hemisphere temperature Tnh and global temperature
Tgl for the last 1000 yrs and also w for the last 335 yrs. We apply MGM method of spectral
analysis elaborated by us that can quantitatively describe both trends and non-stationary
oscillations to evaluate their input in data. Trend in Tnh shows rise since Maunder minimum
with present rate ~0.5 deg.C/100yr correlated with trend in W. High-amplitude 200-yr cycles
in W and in Tgl have passed their maxima and show decrease of their parameters
accompanied by acceleration of Earth for now. The 200-yr cycle variation extracted from data
of interplanetary magnetic field (IMF) measured at the Earth’s orbit also shows the IMF
decline. Moreover, the 200-yr solar cycle contributed to the Tgl rise since ~1890. We suggest
a possible explanation of observed unexplained increasing in the Tnh for the interval 1905-
1940 and its subsequent decrease for 1940-1976 with rate 0.75 deg.C/100yr by variation in w
with period of ~72 yr. Characteristics of the other cycles in Tgl, w and W with the same
periods are also discussed. Based on our results we suggest a possible mechanism for the 22yr
variation in W, Tgl and w derived in our study to be explained. Basic idea of the
mechanism is electromagnetic interaction of the solar wind with magnetosphere and
subsequent entry of the solar wind electro-magnetic flux into polar caps. We used
measurements of the IMF and the solar wind velocity for 1964-2005 to calculate value and
direction of necessary electromagnetic parameters. The flux coming to polar cap leads in the
end to heating of polar ionosphere and atmosphere, temperature contrast between two caps,
intensification of the inter-hemisphere heat machine in the upper atmosphere, change of
angular moment of atmospheric zonal winds (and consequently angular velocity of the Earth
w). The mechanism successfully reproduces the 22-yr variations in W, Tgl and w.