Influence of Climate Regime Shift on the Abrupt Change of Tropical Cyclone Activity in Various Genesis Regions

In this chapter, we reported the effect of basin-scale climate regime shift (CRS) on the abrupt change of tropical cyclone (TC) activity in various genesis basins, including the Pacific, Atlantic, and Indian Oceans. An analysis of regime shift index reveals that the worldwide TC activity experienced four significant abrupt changes during 1960-2014, including (i) an abrupt increase/decrease in the eastern North Pacific (ENP)/western North Pacific (WNP) in the early 1970s, (ii) an abrupt increase in the ENP and WNP in the early 1980s, (iii) an abrupt increase in the North Atlantic and ENP in the middle 1990s, and (iv) an abrupt decrease in the WNP and western South Pacific in the late 1990s. Three of them are identified concurrent with a significant CRS. The possible influence of a CRS on the abrupt change of TC activity in various genesis regions is addressed. We demonstrate that a CRS induced time mean state shift results in a rapid change in the large-scale dynamic and thermodynamic conditions, which substantially contributes to the abrupt change of TC activity in various genesis regions. In addition the CRS, the effect of interdecadal variability, such as the interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation, on the abrupt change of TC activity was discussed.