[Lcefiec] PRÓXIMO JUEVES: COLOQUIO ESPECIAL: "Effects of the solar activity on the modes of atmospheric variability in the Southern Hemisphere"

[coloquios]

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                        Coloquio del
Departamento de Ciencias de la Atmósfera y los Océanos DCAO)/
    Centro de Investigaciones del Mar y la Atmósfera (CIMA)

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JUEVES 31 DE OCTUBRE, 16-17 HS, DCAO, 2 PISO, SALA DE REUNIONES DEL 
DCAO


Radan Huth
Profesor de  Charles University
Faculty of Science Dept. of Physical Geography and Geoecology
Institute of Atmospheric Physics, Prague, Czech Republic

Effects of the solar activity on the modes of atmospheric variability 
in the
Southern Hemisphere

The effects of the variations of solar activity on mid-tropospheric 
circulation of the Southern Hemisphere
in terms of modes of low-frequency variability are analyzed. The modes 
are detected by principal component analysis (orthogonally rotated) in 
an S-mode. The analyzed domain is the Southern Hemisphere Extratropics 
south of 20 S (inclusive); the circulation is characterized by 500 hPa 
heights; the analyzed period is 1950-2011. Separate analyses are 
conducted for individual seasons, that is, winter (JJA), spring (SON), 
summer (DJF), and autumn (MAM).
Solar activity is described by Wolf sunspot numbers.
Monthly mean values of both circulation and solar variables enter the 
analysis.
  The modes are detected separately for the months with a low and high 
solar activity, and differences
between the spatial patterns of the modes (principal component 
loadings) are tested for statistical significance.
All the modes detected exhibit variations in their spatial extent, 
position of action centers, and intensity in response to
the solar activity. Our findings include that during solar minima in 
winter, the Southern Annular Mode strengthens
and that the two circumpolar wavenumber-3 wavetrains break down into 
two parts. The strongest effects appear
near to and west of South America and concern mainly the modes 
consisting of two meridional dipoles shifted by
half a wavelength. The one-point correlation maps for the action 
centers of the modes indicate that the changes in
the appearance of the modes are real and not artifacts of the analysis 
method.


2° PISO, Pabellón 2,
Ciudad Universitaria.

¡Los esperamos a todos!

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Grupo Coloquios
Departamento de Ciencias de la Atmosfera y los Oceanos (FCEN-UBA)
Centro de Investigaciones del Mar y la Atmosfera (CONICET-UBA)
Ciudad Universitaria, 2do piso.
email: coloquios en at.fcen.uba.ar
http://www.at.fcen.uba.ar/charlas_not.php
http://www.cima.fcen.uba.ar/espanol/index.htm
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