HR: 0800h
AN: GP41A-03    [Abstracts]
TI: Solar Activity, Earth Rotation and Atmospheric Circulation
AU: Georgieva, K
EM: kgeorg@bas.bg
AF: Solar-Terrestrial Influences Laboratory, Bl.3 Acad. G.Bonchev str., Sofia, 1113, Bulgaria
AU: * Kirov, B
EM: bkirov@space.bas.bg
AF: Solar-Terrestrial Influences Laboratory, Bl.3 Acad. G.Bonchev str., Sofia, 1113, Bulgaria
AB: Earth rotation rate varies on different time-scales - from centuries to days. The seasonal nontidal variations in the Earth rotation rate, or the length of the day (LOD), are believed to be fully explained by large-scale atmospheric motions caused by the temperature differences between the summer and the winter hemispheres. A connection is also supposed between the decadal LOD variations and changes in atmospheric circulation. We demonstrate that the Earth rotation is different in positive and negative solar polarity cycles, therefore even on these time- scales the Earth-atmosphere system is not closed. The correlation between the decadal variations in LOD and atmospheric circulation changes in the beginning of the XX century, moreover it is opposite in the northern and southern hemispheres, so there is no direct relation between the Earth rotation and large-scale atmospheric circulation on decadal time-scales, rather they are both modulated by solar activity. We look for an explanation for the solar activity influences on the Earth rotation and on the atmospheric circulation in the two hemispheres.
DE: 1239 Earth rotation variations
DE: 1650 Solar variability (7537)
DE: 2162 Solar cycle variations (7536)
DE: 3319 General circulation (1223)
DE: 7974 Solar effects
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly