Report of Solar Geophysical Activity (RSGA)

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 241 Issued at 2200Z on 29 Aug 2013

IA.  Analysis of Solar Active Regions and Activity from 28/2100Z to
29/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C1 event observed at
29/0434Z from Region 1836 (N15E36). There are currently 3 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be very low
with a chance for a C-class flares on days one, two, and three (30 Aug,
31 Aug, 01 Sep).

IIA.  Geophysical Activity Summary 28/2100Z to 29/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 440 km/s at
28/2143Z. Total IMF reached 5 nT at 29/2049Z. The maximum southward
component of Bz reached -2 nT at 29/1903Z. Electrons greater than 2 MeV
at geosynchronous orbit reached a peak level of 134 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on days one and two (30 Aug, 31
Aug) and quiet to active levels on day three (01 Sep).

III.  Event probabilities 30 Aug-01 Sep
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           29 Aug 109
Predicted   30 Aug-01 Sep 108/105/108
90 Day Mean        29 Aug 114

V.  Geomagnetic A Indices
Observed Afr/Ap 28 Aug  008/011
Estimated Afr/Ap 29 Aug  003/003
Predicted Afr/Ap 30 Aug-01 Sep  014/020-016/020-011/012

VI.  Geomagnetic Activity Probabilities 30 Aug-01 Sep
A.  Middle Latitudes
Active                40/40/20
Minor Storm           25/25/05
Major-severe storm    05/05/01
B.  High Latitudes
Active                10/10/15
Minor Storm           25/25/30
Major-severe storm    65/60/30

Radio Events Observed 23 Aug 2013
A.  245 MHz Bursts
Start  End   Peak Flux  Time of Peak  Duration
0000   0000    110          0000        0000  
0044   0044    100          0044        0000  
B.  245 MHz Noise Storms
No 245 MHz Noise Storms Observed.

Radio Events Observed 29 Aug 2013
A.  245 MHz Bursts
No 245 MHz Burst Observed.
B.  245 MHz Noise Storms
No 245 MHz Noise Storms Observed.

Solar Radio Data

Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves -- the surface of the Sun is 6,000 degrees Kelvin, while the high corona can reach several million degrees Kelvin. Solar radio emissions at different frequencies allow us to observe radiation from different heights in the atmosphere. The lower the frequency, the higher the height of origin. The frequency, like the electron density, decreases uniformly outwards: 245 MHz originates high in the corona, while 15,400 MHz originates in the low corona. The 5 MHz emission corresponds to about 10 solar radii height. For a detailed review, see McLean and Labrum (1985)SOLAR RADIOPHYSICS.

Radio bursts are associated with solar flares. The delay at Earth of the different radio frequencies during burst events is due to the outward movement of the source. Bursts can have temperatures of 10xE12 degrees Kelvin. Large bursts last 10 to 20 minutes on average. Longer radio noise storms of persistent and variable high levels of radiation originate in sunspot groups, areas of large, intense magnetic fields. These storms are strongly circularly polarized due to the intense magnetic fields.

http://www.ngdc.noaa.gov/stp/solar/solarradio.html