Open Access

Table 1.

Statistical features X1, …, Xp calculated for each extracted magnetogram feature Y of the SWAN-SF dataset.

Group Stat. feature Xk Description
Main min Y minimum
max Y maximum
Y ¯ $ \bar{Y} $ mean
Y $ \tilde{Y} $ median
IQR(Y) interquartile range
σ(Y) standard deviation
Var(Y) variance
γ1(Y) skewness
κ(Y) kurtosis

Ext 1 min ∂tY gradient minimum
max ∂tY gradient maximum
t Y ¯ $ \overline{\partial_t Y} $ gradient mean
t Y $ \widetilde{\partial_t Y} $ gradient median
min ∂t2Y second derivative minimum
max ∂t2Y second derivative maximum
t 2 Y ¯ $ \overline{\partial_t^2 Y} $ second derivative mean
t 2 Y $ \widetilde{\partial_t^2 Y} $ second derivative median

Ext 2 | t Y | ¯ $ \overline{| \partial_t Y |} $ average absolute change
| t 2 Y | ¯ $ \overline{| \partial_t^2 Y |} $ average absolute change of gradient
algorithmic average slope of monotonically
increasing sequences
algorithmic average slope of monotonically
decreasing sequences
algorithmic slope of longest monotonically
increasing sequence
algorithmic slope of longest monotonically
decreasing sequence
Y|Y| last value

Notes. We distinguish the common (main) summary statistics from extensions that include statistics on time derivatives (Ext 1) and descriptions of long-term trends for the individual features (Ext 2).

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