Thursday, March 17, 2011

Weekly Propagation Forecast Bulletins

Product: Weekly Highlights and Forecasts
:Issued: 2011 Mar 15 1909 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact: www.swpc.noaa.gov/weekly.html
#
# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 07 - 13 March 2011

Solar activity ranged from low to high levels during the period. Early on 07 March, activity levels increased rapidly from low to high levels. Regions 1164 (N24, L=164, class/area Ekc/760 on 07 March), 1165 (S20, L=184, class/area Fko/420 on 07 March) and 1166 (N09, L=092, class/area Ekc/750 on 10 March) produced a total of seven M-class events on the 07 March, the largest was an M3.7 X-ray event from Region 1164 observed at 07/2012Z. Associated with this event was a Type II Sweep (1133 km/s), a large 10cm Burst (23,000 sfu) and a full-halo CME with an estimated plane-of-sky velocity of 2180 km/s. Earlier on 07 March, Region 1166 produced an M1.9/Sf with associated Type II (1320 km/s) and Type IV Sweep signatures and a partial-halo CME with an estimated plane-of-sky velocity of 634 km/s. Activity levels remained high on 08 March due to an M5.3/1f flare observed from Region 1165 at 08/1044Z. High levels persisted on 09 March when Region 1166 produced a X1.5/2b flare at 09/2323Z. Activity decayed to moderate levels on 10 March due to a single M1.1 at 10/2241Z, most likely from Region 1166. By 11 March, levels decayed further to low levels as C-class activity was observed, all from Region 1166. Moderate levels returned on 12 March due to an M1.3/1n observed from Region 1166 at 12/0443Z with an associated Type II Sweep (454 km/s). Later on the 12th, Region 1166 produced a C9.6/1f flare with another Type II Sweep (954 km/s). On 13 March,
levels decreased again to low levels with Region 1166 and Region 1169 (N20, L=060, class/area Cro/290 on 13 March) producing C-class events.

A greater than 10 MeV proton event, at geosynchronous orbit, was observed from 8-10 March due to the M3.7 event from 07/2012Z from Region 1164. The event began at 08/0105Z, reached a maximum flux of 50 pfu on 08/0800Z, and ended at 10/1210Z.

The greater than 2 MeV electron flux at geosynchronous orbit was at high levels from 07-09 March. Mostly moderate levels were observed until March 13, when a return to high levels was observed.

Geomagnetic field activity ranged from quiet to minor storm levels with isolated major to severe storm periods observed at high latitudes. From 07 March through early on 10 March, the geomagnetic field was at quiet to unsettled levels with isolated high latitude active periods. At about 10/0600Z, the ACE spacecraft observed a shock which was most likely the result of the arrival of the 07 March CME activity. Wind speeds increased from about 300 km/s to near 375 km/s while the Bz component of the IMF turned south to about -9 nT. The geomagnetic field responded with unsettled to active conditions, with major to severe storm levels observed at
high latitudes. These conditions persisted through the remainder of the summary period. At about 11/1400Z, density, temperature, and wind speed began to rise while the Bz component indicated fluctuations between +/- 10 nT. These signatures were consistent with a co-rotating interaction region (CIR) in advance of a recurrent coronal hole high speed stream (CH HSS). Solar wind velocities continued a gradual rise through the remainder of 11 March into 12 March and peaked near 600 km/s at 12/0858Z. On 13 March, a gradual decrease in solar wind velocity was observed with velocities holding steady near 550 km/s

Forecast of Solar and Geomagnetic Activity 16 March - 11 April 2011

Solar activity is expected to be at very low levels with a chance for C-class events from 16-24 March. An increase to low to moderate levels is expected for the remainder of the period with the return of old Regions 1165 and 1164 on 25 March and old Region 1169 on 31 March.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at moderate levels from 16 - 19 March. Normal background levels are expected to prevail during 20 - 28 March. High levels are expected to return from 29 March - 05 April and then a decrease to normal background levels is expected for the remainder of the period.

Geomagnetic field activity is expected to be at mostly quiet levels from 16 - 27 March. An increase to active to minor storm levels is expected from 28 -31 March in response to a recurrent CH HSS. A return to mostly quiet levels is expected from 01 - 06 April. Quiet
to unsettled conditions with a chance for an isolated active period from 07 - 10 April is expected in response to another recurrent CH HSS. A return to quiet levels is expected for the remainder of the period.

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2011 Mar 15 2010 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact: www.swpc.noaa.gov/wwire.html
#
# 27-day Space Weather Outlook Table
# Issued 2011-03-15
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2011 Mar 16 100 5 2
2011 Mar 17 100 10 3
2011 Mar 18 100 8 3
2011 Mar 19 95 5 2
2011 Mar 20 90 5 2
2011 Mar 21 85 5 2
2011 Mar 22 80 5 2
2011 Mar 23 80 5 2
2011 Mar 24 85 5 2
2011 Mar 25 90 5 2
2011 Mar 26 90 5 2
2011 Mar 27 95 5 2
2011 Mar 28 95 18 4
2011 Mar 29 100 15 3
2011 Mar 30 100 10 3
2011 Mar 31 110 8 3
2011 Apr 01 110 5 2
2011 Apr 02 110 5 2
2011 Apr 03 110 5 2
2011 Apr 04 110 5 2
2011 Apr 05 110 5 2
2011 Apr 06 110 5 2
2011 Apr 07 105 7 2
2011 Apr 08 105 7 2
2011 Apr 09 100 7 2
2011 Apr 10 100 5 2
2011 Apr 11 95 5 2
(NOAA)

Propagation observations
As at March 17 2011, the 10.7 cm solar flux had dropped to 95, and the daily SSN to 41. These are very low levels, even though solar cycle 24 is progressing slowly!

So not much action above 12 MHz for multi-hop long-haul transmissions over darkness paths.

I did some research in the 11 MHz band yesterday in the Warrandyte State Park, 30 mins from here, 20 km east of central Melbourne. This was at the eastern end of the Pound Bend Picnic area, next to the Yarra. The Eton E5 and a 3 m random antenna yielded many signals in the mid afternoon window, 0430 to 0500, with longpath dominating from Europe, Africa, and the Middle East and shortpath from Asia and the Americas.

This summary of key occupancies of March 17 may be of interest

11640 IRAN VOIRI Turkish *0500
11645 GREECE VOG Greek *0500
11740 EGYPT R. Cairo, Setswana
11805 UZBEKISTAN CVC-Tashkent Hindi
11815 BRAZIL R. Brazil Central
11860 CYPRUS BBC English
11870 USA WEWN Spanish
11895 ROMANIA English
11925 IRAN VOIRI Hebrew
11935 IRAN VOIRI Dari
11980 TAJIKISTAN RFA-Dushanbe Chinese
12010 CUBA RHC Spanish
12015 SRI LANKA R. Farda, Iranawela, Farsi
12025 IRAN VOIRI Russian *0500
12030 RUSSIA VOA-Petropavlovsk English
12035 CYPRUS BBC English
12040 CUBA RHC Spanish
12070 RUSSIA VOR-Moscow Russian
(Bob Padula, Australia/Cumbre DX)