The Effect of Australian Continent Thermal Forcing on Anomalous Variations of Circulation Systems in the Northern and Southern Hemispheres
Xu Xiangde(Academy of Meteorological Science, SMA, Beijing 100081)Zhao Tianliang, He Jinhai and Zhu Qiangen(Nanjing Institute of Meteorology, Nanjing 210044)
The correlation between the thermal forcing of the Australian continent and anomalies of circulaiton systems in the Northern and Southern Hemispheres have been investigated by a simplified numerical model consisting of the dynamical framework of the OSU -GCM and a Newtonian heating term. The differences between results of simulations with different equilibrium temperatures reflect the effects of local thermal forcing on the anomalous response of the global circulations. The results of numerical experiments indicate that: the thermal distribution of sea-land in the Northern and Soutehrn Hemispheres is advantageous to the intensification of planetary - scale meridional circulations in the Northern and Southern Hemispheres and to the formation of cross - equatorial flows; the thermal forcing of the Australian continent in the Southern Hemisphere may distinctly affects the state of the jet in the northern mid -latitude westerlies through the lateral coupling of easterlies and westerlies; the meridional energy dispersion of 2D Rossby waves may be an important cause for the effects of thermal forcing of the Australian continent on anomalous variations of stationary circulation systems in the Northern Hemisphere, and the propagating paths of meridional wavetrains forced by the Australian thermal forcing are very similar to PNA and EU teleconnection patterns.