Table 3 Standard deviation ellipse parameters.
Year | Area (million/km2) | Minor semi axis (km) | Major semi axis (km) | Rotation (°) | Shape index |
|---|---|---|---|---|---|
2011 | 7.972 | 0.978 | 1.529 | 24.104 | 0.640 |
2012 | 7.906 | 0.964 | 1.521 | 21.482 | 0.634 |
2013 | 7.797 | 0.958 | 1.495 | 22.800 | 0.641 |
2014 | 7.769 | 0.956 | 1.488 | 22.168 | 0.642 |
2015 | 7.821 | 0.963 | 1.497 | 22.704 | 0.643 |
2016 | 7.917 | 0.976 | 1.515 | 24.431 | 0.644 |
2017 | 8.004 | 0.989 | 1.530 | 28.315 | 0.646 |
2018 | 8.037 | 0.996 | 1.534 | 29.666 | 0.649 |
2019 | 8.037 | 0.997 | 1.533 | 30.931 | 0.650 |
2020 | 8.126 | 0.984 | 1.569 | 27.234 | 0.627 |