c © TERRAPUB, Tokyo, 2009. Variability in the stratosphere: The sun and the QBO

• Main Authors: Edited T. Tsuda, R. Fujii, K. Shibata, M. A. Geller, Karin Labitzke, Markus Kunze
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Midwinter
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.576.2216; http://www.terrapub.co.jp/onlineproceedings/ste/CAWSES2007/pdf/CAWSES_257.pdf

Large effects of solar variability related to the 11-year sunspot cycle (SSC) are seen in the stratosphere, but only if the data are grouped according to the phase of the QBO (Quasi-Biennial Oscillation). New results based on an extended, 66-year long data set fully confirm earlier findings and suggest a significant effect of the SSC on the occurrence of the Major Midwinter Warmings (MMWs) over the Arctic as well as on the strength of the stratospheric polar vortex and on the mean meridional circulation. By means of teleconnections the dynamical interaction between the Arctic and the Tropics in the stratosphere and in the troposphere is shown for the whole data set and compared with the anomalies of single events. The results suggest strongly that dur-ing the northern winter the teleconnections between the Arctic and the Tropics were determined by the MMWs and the undisturbed, cold winters, respectively. These events in the stratosphere depend, however, on the 11-year SSC and on the QBO. The stratosphere is least disturbed during the northern summer when the interannual vari-ability is small. And if the different phases of the QBO are introduced, a large solar signal is found in the eastphase of the QBO (more than two standard deviations). It is shown that the QBO not only modulates the solar signal on the decadal scale, but that the QBO is itself modulated by the solar variability. 1