[Ips-msgr] IPS Monthly Report - April 02
rwc
rwc at ips.gov.au
Fri May 3 10:52:53 EST 2002
SUBJ: IPS MONTHLY SUMMARY - APRIL 2002
ISSUED BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
1. SOLAR-GEOPHYSICAL INDICES
SOLAR AUST AUST
Day 10 cm flux A-INDEX T INDEX
01-Apr 207 10 161
02-Apr 206 10 156
03-Apr 209 12 147
04-Apr 216 6 158
05-Apr 217 2 151
06-Apr 206 2 150
07-Apr 200 6 161
08-Apr 206 2 151
09-Apr 205 2 152
10-Apr 194 4 152
11-Apr 197 12 153
12-Apr 212 12 162
13-Apr 226 11 160
14-Apr 210 11 161
15-Apr 203 5 156
16-Apr 196 6 151
17-Apr 194 27 142
18-Apr 188 32 142
19-Apr 180 40 138
20-Apr 177 29 113
21-Apr 173 7 103
22-Apr 170 10 125
23-Apr 175 22 121
24-Apr 177 8 126
25-Apr 167 3 127
26-Apr 163 2 129
27-Apr 157 11 141
28-Apr 147 17 144
29-Apr 153 8 133
30-Apr 153 6 130
10 CM SUNSPOT SUNSPOT AUST AUST No of
FLUX NUMBER NUMBER A-INDEX T INDEX FLARES
Monthly Monthly Yearly Monthly Monthly >M1.0
Month Average Average Average Average Average
Apr 01 178.3 108.2 107.6 14.4 129.4 45
May 01 148.7 97.3 108.7 7.1 118.0 11
Jun 01 173.7 134.0 109.8 5.9 135.8 13
Jul 01 131.3 82.2 111.7 6.5 113.6 2
Aug 01 163.2 106.8 113.6 8.0 113.3 23
Sep 01 233.3 150.7 114.1 9.3 146.8 48
Oct 01 208.2 125.6 114.0 15.8 149.8 36
Nov 01 212.7 106.5 114.4p 16.1 156.1 47
Dec 01 235.6 131.8 112.5p 12.6 144.7 46
Jan 02 226.8 113.9 111.0p 10.9 155.7 21
Feb 02 205.2 108.0 110.5p 11.1 154.4 19
Mar 02 179.5 98.1 106.8p 10.4 165.1 15
Apr 02 189.5 120.4 102.2p 11.2 143.2 17
Monthly T indices
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1992 153 172 155 134 95 80 88 66 68 66 84 90
1993 74 77 79 63 63 64 62 50 37 40 34 43
1994 57 41 42 26 15 14 23 18 20 20 20 20
1995 24 33 23 13 3 11 13 10 13 9 13 7
1996 12 7 4 2 5 2 3 4 4 3 11 15
1997 14 11 10 8 11 5 9 17 32 27 28 38
1998 40 41 43 56 46 56 76 75 86 69 74 93
1999 94 81 89 77 98 123 124* 105* 89 91 123 113*
2000 108 120 158 154 133 133 147 140 124 130 137 140
2001 133 127 137 122 113* 134* 112* 114* 143* 151* 158* 145*
2002 155* 151* 159* 119^ 113^ 107^ 100^ 93^ 86^ 81^ 78^ 75^
2003 72^ 69^ 67^ 64^ 61^ 59^ 57^ 54^ 52^ 49^ 47^ 45^
2004 43^ 41^ 39^ 37^ 35^ 33^ 31^ 29^ 28^ 26^ 24^ 23^
2005 21^ 20^ 19^ 17^ 16^ 15^ 14^ 13^ 12^ 11^ 10^ 9^
2006 8^ 8^ 7^ 6^ 6^ 5^ 5^ 5^ 4^ 4^ 4^ 4^
2007 4^ 5^ 5^ 6^ 7^ 8^ 9^ 11^ 13^ 16^ 18^ 21^
2008 25^ 28^ 32^ 36^ 41^ 45^ 50^ 54^ 59^ 64^ 68^ 73^
* = New data. T index may have changed.
^ = IPS predicted T index.
The IPS Monthly T-index is derived from the observed monthly
median values of foF2 for each hour at up to 40 ionospheric
stations worldwide. These records become available from IPS
stations in Australia very soon after each month, but the
majority are received up to one year later. This means that
the exact observed value of the monthly T-index is not
available until some months later.
The predicted smoothed monthly T-indices are computed by
using a statistical analysis of the observed monthly T-indices
for all solar cycles since 1938. The IPS T-indices may not be
updated each month but only when sufficient new
data becomes available.
===============================================================================
2. FLARES AND SHORT-WAVE FADEOUTS
DATE CLASS M CLASS X FLARE FADEOUT POSSIBLE ON
FLARES FLARES MAX DAYLIGHT HF CIRCUIT
04 Apr 02 M1.4 1048UT
04 Apr 02 M6.1 1532UT 1524-1538UT
09 Apr 02 M2.1/2B 0042UT
09 Apr 02 M1.1 1302UT
10 Apr 02 M8.2/1N 1231UT 1223-1240UT
10 Apr 02 M1.6/1N 1907UT
12 Apr 02 M1.4 1310UT
12 Apr 02 M4.0/1F 1802UT 1731-1817UT
14 Apr 02 M1.4/1F 0351UT
15 Apr 02 M3.7/SF 0014UT 2334-0025UT
15 Apr 02 M1.2/SF 0355UT
15 Apr 02 M1.2 2324UT
16 Apr 02 M2.5/SF 1319UT
17 Apr 02 M2.6/2N 0824UT
21 Apr 02 X1.5 /1F 0151UT 0043-0238UT
24 Apr 02 M1.7/1F 2156UT
30 Apr 02 M1.3 0822UT
10Mev Proton Events:
Begin End
17 04 2002 1530UT 18 04 2002 0050UT
21 04 2002 0235UT 26 04 2002 0515UT
2.1 Comments on Solar Activity.
Solar activity varied from low to high levels this month.
High activity was observed on 4,10, and 21 April. The largest
flare for the month was an X1.5 flare at 0151UT on 21 April.
There was 17 xray flare events during the month, 16 M class
events and 1 X class event.
===============================================================================
3. GEOMAGNETIC DISTURBANCES (for Australian Region)
DATE COMMENTS
17 Apr 02: Minor storm periods observed after moderate sudden
impulse (63nT) at 1107UT.
18 Apr 02: Active to Minor Storm periods observed after weak sudden
impulse (25nT) 1139UT.
19 Apr 02: Active to Minor Storm periods observed after weak sudden
impulse (23nT) 0836UT.
20 Apr 02: Major Storm periods observed early in UT day.
23 Apr 02: Minor Storm periods observed after moderate sudden
impulse (64nT) 0449UT.
28 Apr 02: Quiet to Active.
A broad disturbed interval was observed from 17-20 April.
The strongest disturbance this month was observed on 20 April
when the local A index reached 40. The disturbance on 20 April
was stronger in the northern hemisphere with the planetary
A index reaching 62 and the local A index reaching 29.
===============================================================================
4. IONOSPHERIC DISTURBANCES (for Australian Region)
18-21 Apr 2002 Southern Aus/NZ region MUFs depressed -25%.
Northern Aus region MUFs enhanced 25%.
Generally degraded HF communications observed 18-21 April
at mid to high latitudes. Southern regional MUFs generally
depressed 25% during local daylight hours during this interval.
Northern regional MUFs remained near to 20% enhanced during the
interval. Ionospheric depression response to geomagnetic
activity was stronger in the northern hemisphere due to seasonal
effects. Two proton events which began on 17 and 21 Apr caused
degraded polar HF communications on these days, particularly
the event that began on 21 April with 10Mev flux peaking
at 2520 proton flux units at 2320UT on 21 April.
===============================================================================
5. IPS WARNINGS AND ALERTS ISSUED
WARNINGS:
HF RADIO WARNING:
ISSUE DATE NO BEGIN END
11 Apr 02 12 13 Apr 02 14 Apr 02
14 Apr 02 13 14 Apr 02 16 Apr 02
17 Apr 02 14 17 Apr 02 18 Apr 02
19 Apr 02 15 19 Apr 02 20 Apr 02
21 Apr 02 16 21 Apr 02 21 Apr 02
21 Apr 02 17 21 Apr 02 21 Apr 02
23 Apr 02 18 23 Apr 02 24 Apr 02
GEOMAGNETIC WARNING:
ISSUE DATE NO BEGIN END
10 Apr 02 10 12 Apr 02 13 Apr 02
17 Apr 02 11 17 Apr 02 18 Apr 02
18 Apr 02 12 19 Apr 02 20 Apr 02
19 Apr 02 13 19 Apr 02 20 Apr 02
23 Apr 02 14 23 Apr 02 24 Apr 02
ALERTS:
04 Apr 02: Flare Alert
09 Apr 02: Flare Alert
12 Apr 02: Flare Alert
14 Apr 02: Flare Alert
15 Apr 02: Flare Alert
16 Apr 02: Flare Alert
17 Apr 02: Flare Alert
17 Apr 02: Geomagnetic
18 Apr 02: Geomagnetic
19 Apr 02: Geomagnetic
20 Apr 02: Geomagnetic
21 Apr 02: Flare Alert
21 Apr 02: Geomagnetic
23 Apr 02: Geomagnetic
28 Apr 02: Geomagnetic
SWF ALERTS AND DURATION REPORTS
DATE SWF BEGIN-END (UT)
21 Apr 02: SWF Alert (0054-0509 UT)
IPS Radio and Space Services | email: asfc at ips.gov.au
PO Box 1386 | WWW: http://www.ips.gov.au/asfc
Haymarket NSW 1240 AUSTRALIA | FTP: ftp://ftp.ips.gov.au/users/asfc/
tel: +61 2 9213 8010 | fax: +61 2 9213 8060
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