Correlation between geomagnetic field reversals and climatic variations during Brunhes Chron

SINITO A. M.; ORGEIRA, MARÍA J.; COMPAGNUCCI, R.

Praga

Congreso; 26th IUGG 2015 General Assembly; 2015

INTERNATIONAL UNION OF GEODESY AND GEOPHYSICS

Category: IAGA (Aeronomy, Geomagnetism)Symposium: A09 Open Symposium on Paleomagnetism and Rock Magnetism (Div. I)PosterAbstract title:Correlation between geomagnetic field reversals and climatic variations during Brunhes ChronA.M. Sinito1, M.J. Orgeira2, R.H. Compagnucci3.1Universidad Nacional del Centro, Facultad de Ciencias Exactas, Tandil, Argentina.2Universidad de Buenos Aires-IGEBA, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina.3Universidad de Buenos Aires, Departamento de Ciencias de la Atmosfera y los Oceanos, Buenos Aires, Argentina.Orbital cycles and solar activity are relevant climatic forcings with different frequencies. Therefore, depending on the scale and intensity of climatic variation, the influence of one of them will be more evident. Several authors have analyzed the effect of other variables, such as geomagnetic field (GF).Solar activity is a very important influence, not only on climate, but also on exterior GF. The sun effect should modulate a part of the GF, but this part would be not connected with the main mechanisms of the interior GF, which generate reversals. Some authors suggested that the interior GF could trigger climatic changes, possibly by the influence of the cosmic radiation, since the GF provide an additional shielding for this radiation. Therefore, GF modulates the input of cosmic radiation and, at the same time, there is a correlation between cosmic radiation and cloud coverage.At present there are two main hypotheses about the influence of the GF on climate. One hypothesis suggests that lower GF intensity corresponds to higher cosmic radiation input, higher cloud formation, colder climate. The other hypothesis is associated to the presence of jerks and simultaneous sudden changes of intensity and direction of GF.In this work the GF intensity variations and reversals are connected to main climatic events occurred during Magnetic Brunhes Chron (last 0.7 Ma). Particularly records corresponding to the end of the LMG, MIS3 and MIS5 are analyzed. Some cases of positive and negative correlation between GF and paleoclimate are presented, taking on account the previous hypotheses. The obtained results suggest that the GF reversals are related to periods with decrease of mean ocean surface temperature, or increase of cooling trend started before the reversal.