Solar wind summary (Last 24 hours)

9 February


Solar wind speed ranged from approximately 370 km/s to 465 km/s while
total field measurements ranged from about 4 to 10 nT. The Bz component
was predominately southward through about 09/0715 UTC with a maximum
southward extent of -6 nT. Bz then turned northward with a maximum
northward extent of +7 nT when it turned weakly southward at about
09/1135 UTC. Phi angle was in a negative (towards) sector through
09/0340 UTC where it transitioned to a more positive (away) orientation.
A sector change to negative was observed at 09/1130 UTC.

8 February


Solar wind speed, measured at the ACE spacecraft, remained at nominal
levels until 07/1616 UTC with the arrival of the interplanetary (IP)
shock associated with the arrival of the 04 Feb CME. Elevated solar
wind speeds near 450 km/s have persisted since. A marked increase in
density and temperature were also observed at that time. IMF total field
increased from 5 nT to 11 nT initially after shock arrival followed by a
gradual rise to 15 nT. For several hours after, the total field bounced
between 5 nT and 15 nT before settling in near 10 nT the last few hours
of the period. The Bz component varied between + 13 nT and -9 nT for
most of the period. The Phi angle was positive (away) until 07/2040 UTC
when a short-lived solar sector boundary change (SSBC) to a negative
(towards) orientation was observed. Right around the end of the UT day,
Phi switched back to a positive orientation and remained there until
just before 08/0730 UTC, when it began switching back to a negative
(toward) sector. At approximately this same time, Bz went positive and
winds and temperature increased slightly. These were all likely signs of
a co-rotating interaction region (CIR) or the coronal hole high speed
stream (CH HSS) has already begun to affect the Earth.

7 February


Solar wind parameters remained at nominal levels throughout the period.
Wind speed began the period near 400 km/s and, aside from a few isolated
intervals with speeds above 450 km/s, conditions reflected a slow and
steady decrease to below 350 km/s by the end of the period. Total field
strength was steady between 5 and 7 nT. The Bz component began the
period near -5 nT but eventually settled in to a consistent +/-2 nT. Phi
angle remained in a positive (away) orientation.

6 February


Solar wind continued at nominal levels with speeds ranging between 331
km/s and 451 km/s for most of the period. Total field strength began the
period at 11 nT, but indicated a slow but steady decrease, ending the
period near 6 nT. The Bz component was positive with intermittent
southward deflections as much as -5 nT for the majority of the first
half of the period. Shortly after 06/0200 UTC, Bz dropped to near -4 nT,
where it remained for the remainder of the period. Aside from an hour at
the beginning of the period, Phi angle was in a predominately positive
(away) orientation.

5 February


Solar wind continued at nominal levels with a slow solar wind speed
averaging about 350 km/s. Total field strength ranged from 6 to 10
nT with the Bz component variable at +10 to -4 nT but northward during
most of the period. Phi angle was in a predominately positive (away)
orientation through a majority of the period intermixed with brief
negative (towards) incursions.

4 February


Solar wind continued at nominal levels with a slow solar wind speed
variable between 330 – 380 km/s. Total field strength ranged from 5 to 8
nT with the Bz component variable at -6 to +7 nT. Phi angle was in a
predominately negative (towards) orientation through 04/0327 UTC when a
switch to a positive (away) sector was observed.

3 February


Solar wind continued at nominal levels with solar wind speed in the 360
km/s to 420 km/s range until 02/2318 UTC when an increase in solar wind
speed to 465 km/s occurred. Accompanying this increase were also
increases in density to 7 p/cc and total field from 5 nT to 8 nT. This
was likely indicative of the passage of the 30 Jan CME. Thereafter,
total field remained fairly steady near 7 nT with the Bz component
between +7 nT and -5 nT. Solar wind speed declined to around 360 km/s
by the end of the period. Phi angle was mostly negative (towards) with
minor variations into a positive (away) sector.

2 February


Solar wind parameters were nominal with solar wind speed increasing
slightly through the period from approximately 334 km/s to 380 km/s.
Total field also saw a minor increase from 2 nT to 6 nT while the Bz
component was variable between +/-6 nT. Phi angle was mostly negative
(towards) with minor deviations into a positive (away) sector.

1 February


Solar wind continued at nominal levels with wind speeds ranging from 291
km/s to 355 km/s. Total field ranged from 1 nT to 5 nT with the Bz
component between +3 nT and -2 nT. Phi angle was mostly positive (away)
with a deviation into the negative (towards) sector around 01/1023 UTC.

31 January


Solar wind parameters were nominal with wind speeds ranging from 306
km/s to 417 km/s. Total field was relatively steady between 3 nT and 6
nT with the Bz component mostly north between +4 nT and -3 nT. Phi
angle was consistently positive (away) through the period.