Welcome to the Solar Influences Data Analysis Center (SIDC), which is the solar physics research department of the Royal Observatory of Belgium. The SIDC includes the World Data Center for the sunspot index and the ISES Regional Warning Center Brussels for space weather forecasting.


Over the past 24 hours solar activity has increased. There have been four
B-flares flares originated at NOAA AR 2659 (McIntosh:Dai; Mag.Type:Beta).
The biggest flare B9.2 peaked yesterday (27-Mar-2017) at 18:30 UT. No
Earth-directed CMEs have been detected over the past 24 hours. Solar
electron and proton fluxes have remained at background levels over the past
24 hours. NOAA AR 2659 is expected to produce more B-class and C-class
flares over the next 24 hours.

Solar wind speed was fluctuating around 300 km/s (DSCOVR) until 14:50 UT
yesterday when a small shock was observed in the solar wind due to the
arrival of the 23-May-2017 coronal mass ejection. Initially, solar wind
speed abruptly increased from 303 km/s to 385 km/s and density increased
from 4.6 to 70p/cm3.

The Total Interplanetary Magnetic Field (IMF) strength Bt jumped from 2.5
to 10 nT, while the Bz component jumped to -8.5 nT. Later on yesterday, Bt
reached a maximum of 22.30 nT at 22:30 UT and Bz component reached -20.5 nT
value. Then Bt started to decrease gradually (till 16.5 nT), while Bz
slowly returned to low values (-3.5 nT) being strongly negative. Solar wind
speed is currently (28-May-2017 October, 12:30 UT) below 400 km/s.

Kp index reached moderate storm levels (Kp=6) from 21 UT (2017-05-27) to 03
UT (2017-05-28, today). During 03-06 UT, today Kp reached major storm
levels (Kp=7) and during 06-12 UT again moderate and minor storm levels
(Kp=6, Kp=5). Local K index at Dourbes was mostly at minor to major
storming levels (K=5,4,5,6,7,5) from 21 UT (2017-05-27) to 12 UT
(2017-05-28, today).

Total IMF strength is expected to remain at high levels tomorrow, and Bz
component is not expected to become strongly negative. Solar Wind speed is
expected to remain below 400 km/s. Therefore geomagnetic environment is
expected to remain most probably at active conditions (Kp=4) for the next
two days. However, isolated minor storming episodes (Kp=5) are still

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Daily estimated sunspot number

Most recent alerts

2017 May 28 0919 UTC
As expected, the arrival of 23-May-2017 coronal mass ejection yesterday [more]

2017 May 15 1231 UTC
END OF ALL QUIET ALERT ...................... The SIDC [more]

2017 Apr 03 1504 UTC
A class M5.8 solar X-ray flare occurred on 2017/04/03 with peak time 14:29UT [more]

2016 Nov 05 1349 UTC
A halo or partial-halo CME was detected with the following characteristics: [more]

Science Highlights

May 28, 2017: A coronal mass ejection as the source of a strong geomagnetic storm (NL-FR-EN)

Apr 26, 2017: Works in progress!...

Apr 20, 2017: Impressive solar eruption

Apr 11, 2017: Airplane transits the Sun!

Apr 05, 2017: M-class flares à volonté!

click here for all science highlights


May 28, 2017: A coronal mass ejection as the source of a strong geomagnetic storm (NL-FR-EN)

Oct 26, 2016: High-speed solar wind causes major geomagnetic storm (NL-FR-EN)

May 04, 2016: Mercury Transit

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