Table 1 Information on the geomagnetic observatories used in this study
Code | Name | \(\text{lat}^{\text{GG}}\) | \(\text{lon}^{\text{GG}}\) | \(\text{lat}^{\text{GM}}\) | \(\text{lon}^{\text{GM}}\) | Time interval used for tippers’ estimation |
|---|---|---|---|---|---|---|
API | Apia | \(-13.81\) | \(-171.78\) | \(-15.05\) | 263.35 | \(01/01/2016 - 31/12/2017\) |
ASC | Ascension Island | \(-7.95\) | \(-14.38\) | \(-2.77\) | 57.48 | \(01/01/2014 - 31/12/2015\) |
CKI | Cocos-Keeling Islands | \(-12.10\) | 96.84 | \(-21.56\) | 168.92 | \(01/01/2017 - 31/12/2018\) |
GAN | Gan | 0.69 | 73.15 | \(-8.64\) | 145.33 | \(01/01/2016 - 31/12/2017\) |
GUA | Guam | 13.59 | 144.87 | 5.8 | 216.51 | \(01/01/2017 - 31/12/2018\) |
HON | Honolulu | 20.32 | \(-158\) | 21.65 | 270.85 | \(01/01/2015 - 31/12/2016\) |
IPM | Easter Island | \(-27.2\) | \(-109.42\) | \(-19.17\) | 325.61 | \(01/01/2013 - 31/12/2015\) |
PPT | Pamatai | \(-17.57\) | \(-149.58\) | \(-15.05\) | 285.79 | \(01/01/2015 - 31/12/2016\) |
SHE | St. Helena* | \(-15.90\) | \(-5.75\) | 11.78 | 64.24 | \(01/01/2015 - 31/12/2015\) |
SMA | Santa Maria/Azores* | 36.99 | \(-25.13\) | 43.21 | 53.57 | \(01/05/2018 - 31/09/2019\) |
TDC | Tristan da Cunha | \(-37.07\) | \(-12.31\) | \(-31.70\) | 54.76 | \(01/01/2013 - 31/12/2014\) |