Figure 1
Example of a spatial domain for the Lityński-based circulation type classification.
Source: own elaboration.
Table 1
The matrix of agreement between the results of individual classification schemes (%). Variant names are explained in the text.
| ORG | ||||
|---|---|---|---|---|
| 89.3 | NEW | |||
| 88.0 | 95.6 | NEW1 | ||
| 84.9 | 91.1 | 93.0 | MOD30 | |
| 80.9 | 86.3 | 87.6 | 89.2 | MOD20 |
[i] Source: own elaboration.
Figure 2
The thresholds for the classes of the indices Wp (a), Ws (b) and Cp (c) for 16 January 1948-2015. ORG_u – the upper threshold for the ORG classification; NEW_u – the upper threshold for the NEW classification; MOD20_u – the upper threshold for the MOD20 classification; ORG_I – the lower threshold for the ORG classification; NEW_I – the lower threshold for the NEW classification; and MOD20_I – the lower threshold for the MOD20 classification.
Source: own elaboration.
Figure 3
The value distribution of the Wp, Ws, and Cp indices for January (JAN), April (APR), July (JUL), and October (OCT) 1986-2015. Vertical dashed lines denote the class thresholds according to the formula x̄ ±0.433σ (the NEW1 variant); vertical continuous lines denote the class thresholds according to the percentiles 33 and 67 (the MOD30 variant). Variant names are explained in the text.
Source: own elaboration.
Figure 4
Deviations (%) of the frequencies of individual classes for the indices Wp (a), Ws (b), and Cp (c) from the theoretical equally-likely frequency (where the frequency of each class equals 33.33%), in individual classification variants. Variant names are explained in the text.
Source: own elaboration.
Table 2
Mean absolute error (MAE) for the different variants of the classification algorithm. Variant names are explained in the text.
| Variant | ORG | NEW | NEW1 | MOD30 |
|---|---|---|---|---|
| MAB (pp) | 1.82 | 1.05 | 1.01 | 0.74 |
[i] Source: own elaboration.
Figure 5
Mean absolute error (MAE) for the sub-variants MOD5, MOD10, MOD15, MOD20, MOD25, MOD30, and MOD35 at different periods of time on which the class thresholds are calculated. Variant names are explained in the text.
Source: own elaboration.
Figure 6
Atmospheric circulation types determined using the ORG and MOD20 classifications in comparison with synoptic charts for selected days at 12:00 UTC. Variant names are explained in the text.
Source: own work on the basis of synoptic charts obtained from: Koninklijk Nederlands Meteorologisch Instituut 2018.