High-stability algorithm for the three-pattern decomposition of global atmospheric circulation

Abstract

In order to study the atmospheric circulation from a global-wide perspective, the three-pattern decomposition of global atmospheric circulation (TPDGAC) has been proposed in our previous studies. In this work, to easily and accurately apply the TPDGAC in the diagnostic analysis of atmospheric circulation, a high-stability algorithm of the TPDGAC has been presented. By using the TPDGAC, the global atmospheric circulation is decomposed into the three-dimensional (3D) horizontal, meridional, and zonal circulations (three-pattern circulations). In particular, the global zonal mean meridional circulation is essentially the three-cell meridional circulation. To demonstrate the rationality and correctness of the proposed numerical algorithm, the climatology of the three-pattern circulations and the evolution characteristics of the strength and meridional width of the Hadley circulation during 1979–2015 have been investigated using five reanalysis datasets. Our findings reveal that the three-pattern circulations capture the main features of the Rossby, Hadley, and Walker circulations. The Hadley circulation shows a significant intensification during boreal winter in the Northern Hemisphere and shifts significantly poleward during boreal (austral) summer and autumn in the Northern (Southern) Hemisphere.