Table 1 Decomposition of DGPI trend change by region.

From: Anthropogenic forcing changes coastal tropical cyclone frequency

%

OMEGA

V-SHEAR

M-SHEAR

VORT

DGPI (total)

US Atlantic Coast

26

40

11

23

100

Hawaii

47

56

−16

12

100

South China Sea

70

53

−27

4

100

Japan-Korea

21

16

55

8

100

Madagascar

119

110

−83

−46

100

  1. The DGPI equation (see Method) is linearized by taking the logarithm. The mean log(DGPI + 1) change for each region highlighted by the green boxes in Fig. 4a–c is broken down into the relative contribution (in a unit of %) of four terms related to the change of absolute vorticity (VORT), vertical motion (OMEGA), vertical wind shear (V-SHEAR), and meridional shear vorticity (M-SHEAR). A positive contribution of one term means the logarithm of the trend difference of this term shows the same sign as the mean log(DGPI + 1) trend difference. Bold font highlights the largest contribution in each region.
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