Table 1 Summary of data selection criteria for Swarm and ground observatory data

Sampling

–

Every 20th datum

Hourly mean

Kp, Kp\(_\text {-3h}\)

3 h planetary K index at datum and in preceding 3 h interval

≤ 2₀, ≤ 2₀

\(\le \; \) 2\(_\text {+}\), –

|Dst| [nT], |dDst/dt| [nT h\(^{-1}\)]

Storm time disturbance and its rate of change per hour at datum

≤ 30, ≤ 2

–, \(\le \; \) 5

IMF B\(_\text {x}\), B\(_\text {y}\), B\(_\text {z}\) [nT]

Projected interplanetary magnetic field at datum

\(\le |\) 10|, \(\le |\)3|, 0 \(\le \; \)× \(\le \; \) 6

–, –, \(\ge\) − 2

v\(_\text {sw}\) [km s\(^{-1}\)]

Projected solar wind velocity at datum

\(\le \; \) 450

–

LT (\(<|\)55\(^\circ \)GMD|)

Local time at GMD latitudes below |55\(^\circ \)|

23:00 \(\le \; \) x \(\le \; \) 05:00

01:00 \(\le \; \) x \(\le \; \) 02:00

|d−m\(_\text {prior}\)| [nT]

Absolute difference between datum and a preliminary version of our parent model

\(\le \; \)100

–

|F–|B|| [nT]

Absolute difference between ASM and magnitude of VFM data

\(\le \; \)2

–

E\( {m}\) (\(\ge \) |55\(^\circ \)GMD|) [mV m\(^{-1}\)]

Hourly mean of 1 minute merging electric field, calculated as in Newell et al. (2007)

\(\le \; \)0.8

–