An Analysis of Anomalous Winter and Spring Tornado Frequency by Phase of the El Niño/Southern Oscillation, the Global Wind Oscillation, and the Madden-Julian Oscillation
Table 2
Mean (mean rank) of daily tornado count by GWO and MJO phase.
GWO phase
1
2
3
4
5
6
7
8
Active EN DJF
0.0 (70.0)
—
—
—
—
1.5 (83.3)
1.3 (92.8)
2.3 (96.3)
Active EN MAM
3.8 (100.5)
2.9 (86.8)
7.5 (106.9)
3.2 (81.1)
3.6 (83.9)
3.3 (89.5)
2.7 (98.3)
2.8 (88.2)
Inactive LN DJF
0.1 (89.4)
0.1 (90.5)
0.1 (86.4)
0.1 (87.2)
0.0 (84.0)
0.5 (100.5)
0.8 (106.5)
0.1 (90.2)
Inactive LN MAM
2.3 (115.4)
3.6 (100.0)
1.4 (88.8)
1.0 (79.8)
2.1 (93.6)
1.8 (111.0)
2.6 (79.8)
1.8 (84.8)
MJO phase
Active EN DJFa
3.5 (113.2)
0.4 (90.0)
1.9 (101.4)
0.7 (81.2)
1.1 (80.6)
4.0 (119.9)
1.3 (80.5)
0.3 (80.6)
Active EN MAMb
1.1 (58.0)
2.5 (85.4)
2.6 (87.3)
5.9 (116.1)
1.2 (72.5)
1.5 (83.3)
4.5 (101.9)
3.1 (97.8)
Inactive LN DJF
0.4 (100.3)
0.0 (84.0)
0.1 (88.0)
<0.1 (87.3)
0.1 (91.4)
0.2 (91.7)
0.5 (92.7)
0.1 (87.9)
Inactive LN MAM
2.0 (96.6)
2.2 (87.3)
2.7 (92.3)
0.5 (70.1)
2.3 (103.0)
2.6 (96.7)
2.0 (95.6)
1.7 (94.5)
aA Kruskal–Wallis test indicates that the mean rank of tornado count varies across the phases of MJO (X2 = 23.9; df = 7; ). Post hoc comparisons show that the mean rank of tornado count is greater in phase 6 than in phases 4, 7, and 8. bA Kruskal–Wallis test indicates that the mean rank of tornado count varies across the phases of MJO (X2 = 17.9; df = 7; ). Post hoc comparisons show that the mean rank of tornado count is greater in phase 4 than in phase 1.
