Table 1 Model covariates used to build predictor models, including ENSO indices (1–10) and non-ENSO indices (11–16).

From: A new approach for location-specific seasonal outlooks of typhoon and super typhoon frequency across the Western North Pacific region

 

Index

Detail

Source

References

1

NINO1 + 2

Average SSTs in the NINO1 + 2 region (0°–10° S, 90°–80° W)

ERSSTv543

44

2

NINO3

Average SSTs in the NINO3 region (5° N–5° S, 150°–90° W)

3

NINO3.4

Average SSTs in the NINO3.4 region (5°–5° S, 170°–120° W)

45

4

NINO4

Average SSTs in the NINO4 region (5° N–5° S, 160° E–150° W)

46

5

Southern Oscillation Index (SOI)

Atmospheric index calculated using the pressure differences between Tahiti and Darwin

NOAA CPC

47

6

Coupled ENSO Index (CEI)

Three-month smoothed NINO3.4 and SOI using a 1970–2018 anomaly period

ERSSTv5 for NINO3.4 and NOAA CPC for SOI

48

7

Oceanic NINO Index (ONI)

Three-month running mean of NINO3.4 SSTs, based on changing base period consisting of sliding centred 30-year base periods

ERSSTv543

49

8

Trans NINO Index (TNI)

Difference in normalised SST anomalies between the NINO1 + 2 and NINO4 regions

HadSST1.150 until Nov 1981 and NCEP NOAA OI51 after

44

9

ENSO Modoki Index (EMI)

Difference in monthly SSTs between Modoki A (10° N–10° S, 165° E–140° W), Modoki B (5° N–15° S, 110°–70° W), and Modoki C (20° N–10° S, 125°–145° E) and calculated using the following equation:

EMI = Modoki A −  (0.5*Modoki B) − (0.5*Modoki C)

ERSSTv543

24

10

ENSO Longitudinal Index (ELI)

Index based on the longitudinal extent of ENSO

52

52

11

Indian Ocean Dipole (IOD) East box (IOD E)

SST anomalies in the IOD E region (eastern pole of DMI; 0°–10° S, 90°–110° E)

ERSSTv543

40

12

Indian Ocean Dipole (IOD) West box (IOD W)

SST anomalies in the IOD W region (western pole of the DMI; 10° N–10° S, 50°–70° E)

ERSSTv543

13

Dipole Mode Index (DMI)

Difference in SST anomalies between IOD W and IOD E

ERSSTv543

14

Pacific/North American Pattern (PNA)

Rotated Principal Component Analysis (RPCA) applied to monthly standardised 500mb height anomalies between 20° and 90°N

NOAA CPC

41

15

Quasi-Biennial Oscillation (QBO)

Zonal average of the equatorial 30mb zonal wind

NOAA PSL

31

16

SST Pacific Meridional Mode (PMM)

Maximum Covariance Analysis (MCA) to SSTs (21° S–32° N, 74° W–15° E)

NCEP SST

42

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