Changes of the association between stratospheric temperature and solar activity along three solar cycles

NIEVES ORTIZ DE ADLER; ANA G. ELIAS

Toulouse

Congreso; 10th Scientific Assembly of the International Association of Geomagnetism and Aeronomy; 2005

IAGA, International Association of Geomagnetism and Aeronomy

Seasonal and annual stratospheric temperature deviations from the 1961-1990 mean at 50, 30, 20 and 10 mb for north sub-tropic (10ºN-30ºN) and equatorial (10ºS-10ºN) zones obtained from the NOAA Air Resources Laboratory are analyzed. Temperature data are based on five radiosonde stations within each of these zones and within the longitude band from Ascension Island (7ºS, 345ºE) to Singapore (1ºN, 104ºE). For each pressure level, and for each zone, the data were grouped by solar cycle. The points of each scatter plot for solar cycles 20, 21,and 22 of temperature in terms of F10.7 were linked according to their chronological order. In most of the cases the plots follow an ordered pattern which resemble an oval loop with an area which is related to the correlation coefficient of the linear regression between temperature and F10.7. The correlation coefficients change from cycle to cycle. An increasing trend is clear at 50 mb from solar cycle 20 to 22 and a decreasing one at 10 mb. The height variation of the correlation coefficients for each solar cycle has also been analyzed. Considering each solar cycle separately, as done in this work, allows the detection of a possible secular variation of the association between temperature and solar activity.