The Halloween Storm Period of 2003

As noted in Section 2.2.8, The October 2003 period was an extraordinary period of significant solar activity. Region 486 produced two enormous x-ray flares, with accompanying CMEs, on 28 and 29 October, 2003. The amplitudes of the flares were ~ XI7 and ~ XI0 respectively as depicted in Figure 2-13. Extreme (i.e., G5) magnetic storms were introduced following impact of both of the CMEs. The second storm has since been termed the Halloween storm in view of its coincidence with the well-known holiday, but its impact on the ionosphere made it noteworthy as well. Figure 2-29 shows the flare activity for the period of interest, and Figure 2-30 shows the magnetic activity response. During these stormy periods, high frequency communications were virtually impossible over uncompensated high latitude paths. The variation in electron concentration was significant for midlatitude sites as well as high latitude sites. We discuss these ionospheric effects in Chapter 3, and some factors related to specific systems in Chapter 4. Indeed, telecommunication performance was degraded for a variety of system types. Ionospheric effects upon the FAA WAAS system are indicated in Chapter 4. The U.S. Department of Commerce (i.e., NOAA, National Weather Service) has published a Service Assessment [NOAA-NWS, 2004] detailing the space weather storms of October 19th through November 7th, 2003. Table 2-10 is a chronology of events

Table 2-10: A Summary of Events for the period October 19-November 7, 2003

o October 28, 2003:1110 UTC: X17 flare from Region 486 o XI7 flare produces R4 (severe) radio blackout & solar radio bursts o X17 flare followed by radiation storm, reaching S3 (strong) levels and S4

(severe) levels after 13 hours o XI7 flare was followed by fast CME. The CME was observed by LASCO on SOHO spacecraft, and had a speed of 2,125 km/sec. The CME reached the earth in 19 hours., o The X17-related CME impacted the ionosphere and produced a G5 (extreme) geomagnetic storm. This storming lasted 27 hours. This was the 6th most intense storm since 1932. o October 29:2049 UTC: X10 flare from Region 486 o X10 flare produces R4 (severe) radio blackout o X10 flare produces S3 radiation storm o XI0 flare followed by Fast CME with a speed of 1,948 km/sec, reaching the earth in 19 hours. (1600 UTC on October 30, 2003) o The XlO-related CME impacted the earth and introduced a G5 (extreme)

geomagnetic storm lasting 24 hours, o November 4, 2003: 1950 UTC: X28 flare emitted from region 486. This flare occurred near the west limb of the sun, so the impact was minimal. The CME was directed away from the earth. The X28 flare is thought to be the largest since these events have been recorded.

10"

10"

510"

GOES Xray Flux (5 min data)

Begin: 2003 Nov 2 000 UTC

10"

GOES Xray Flux (5 min data)

Begin: 2003 Nov 2 000 UTC

10"

10"

10"

F 1

i =i i i -i

i

i

i

Li

I

L

i

1

I '

r

\ 1 ilk 1

Httlrt 1-

r i. A. w

Vi J Ù J

III llv^ »

3 H

flUV Hi* I c ^ M 1 l_ 1

1 1

»\l 3 ' 3

Ê 1 1 i i i i i i i 1

i a 1 i i i i i i i i i i i i i i i i i

CO LU

O CD

ov 2

Nov 3 Nov 4

Universal Time

CO LU

O CD

CO UJ

un ov 2

Nov 3 Nov 4

Universal Time

Nov 5

Figure 2-29: GOES X-ray flare activity for the Halloween storm period. Data provided by NOAA-SEC, Dept. of Commerce

Estimated Planetary K tadex (3 honor data) Begin: 2003 Oct 29 0000 UTC 9

Figure 2-29: GOES X-ray flare activity for the Halloween storm period. Data provided by NOAA-SEC, Dept. of Commerce

Estimated Planetary K tadex (3 honor data) Begin: 2003 Oct 29 0000 UTC 9

Oct 29

X?pdated 2003 Nov 1 02:45:03 UTC

Oct 30 Oct 31

Unlmul Time

NOAA/SEC Bouldor, CO USA

Oct 29

X?pdated 2003 Nov 1 02:45:03 UTC

Oct 30 Oct 31

Unlmul Time

NOAA/SEC Bouldor, CO USA

Figure 2-30: Magnetic activity for Halloween storm period. (Data provided by NOAA-SEC, Dept. of Commerce, Boulder CO.)

Given the enormity of the Halloween storm events discussed above, one might say that such isolated situations are sufficient to justify a significant investment in space weather observations and around-the-clock vigilence. But this probably not the case. One has to recognize that such events are not normal occurrences. While they may play havoc, they are rare. From the NOAA assessment report [NOAA-NWS, 2004] a listing of the top 20 radiation storms and the top solar flares have been tabulated. These are given in Tables 2-11 and 2-12. Data for solar cycles 21, 22, and 23 are listed. We see that the Top-20 listing includes 3, 9, and 8 radiation events for cycles 21, 22, and 22 respectively. These events may cause PCA events (of importance to HF communication over the poles) and can lead to radiation exposure for passengers and crew for transpolar flights. One radiation storm from the October-November 2003 period appears in Table 2-11. This occurred on October 28, 2003 (rank 4).

The X-ray flare listing in Table 2-12 indicates that the largest flares numbered 4, 10, and 6 for solar cycles 21, 22, and 23 respectively. Flares cause short wave fades (SWFs) for HF systems, but their importance may be greater as an indicator of delayed effects such as radiation storms, PCA events, and geomagnetic storms. There are 3 flares from the October-November 2003 period in Table 2-12: 11-04-2003 (rank 1), 10-28-2003 (rank 4), and 10-29-2003 (rank 20).

Probably the more important listing is that of magnetic storms. In this instance the NOAA Service Assessment [NOAA-NWS, 2004] has provided the Top-30 Geomagnetic storms since 1932 based upon the Potsdam "running" Ap index. It is well known that geomagnetic storms introduce significant ionospheric perturbations of global significance. Table 2-13 indicates that the largest geomagnetic storm was on December 18, 1941 and that two storms during the "Halloween" period of 2003 (i.e., October 29 and October 30) were respectively ranked 6 and 16 on the 1932-2003 list.

Table 2-11: The Greatest Twenty Radiation Storms (GOES proton flux > 10 MeV since 1976)

Rank

Intensity

Date

Rank

Intensity

Date

(pill) x 103

(mm-dd-yyyy)

(pfu) x I0!

(mm-dd-yyyy)

1

43

03-23-1991

11

7.3

11-30-1989

2

40

10-19-1989

12

4.6

05-09-1982

3

31.7

11-04-2001

13

4.5

09-29-1989

4

29.5

10-28-2003

14

3.5

03-08-1989

5

24

07-14-2000

15

3

06-04-1991

6

18.9

11-22-2001

16

2.9

06-11-1982

7

14.8

11-08-2000

17

2.7

10-30-1992

8

12.9

09-24-2001

18

2.52

04-21-2002

9

10

02-20-1994

19

2.5

04-25-1984

10

9.2

08-12-1989

20

2.36

10-01-2001

Table 2-12: Top Twenty Solar Flares**

Rank

X-ray

Date

Rank

X-ray

Date

Intensity

(mm-dd-yyyy)

Intensity

(mm-dd-yyyy)

1

X28e

11-04-2003

11

X12

12-15-1982

2

X20e

08-16-1989

12

X12e

06-04-1991

3

X20e

04-02-2001

13

X12e

06-06-1991

4

X17

10-28-2003

14

X12e

06-11-1991

5

X15e

07-11-1978

15

X12e

06-15-1991

6

XI 5e

03-06-1989

16

X10

12-17-1982

7

XI 3e

04-24-1984

17

X10

05-20-1984

8

X13e

10-19-1989

18

X10

01-25-1991

9

X12e

06-06-1982

19

X10

06-09-1991

10

XI 2e

06-01-1991

20

X10

10-29-2003

** NOAA GOES X-Ray instrument, as observed since 1976. The "e" affixed to the X-ray intensity indicates that the value is estimated since the saturation level for the instrument was reached. By 1993, the saturation level was elevated to the X17.4 level.

Table 2-13: The Top-30 Geomagnetic Storms

Rank

Ap Value

Date

Rank

Ap Value

Date

1

312

09-18-1941

16

220

10-30-2003

2

293

11-12-1960

17

216

07-08-1958

3

285

03-13-1989

18

215

03-28-1946

4

277

03-23-1940

19

214

09-22-1946

5

258

10-04-1960

20

212

03-01-1941

6

252

10-29-2003

21

212

07-26-1946

7

252

07-15-1959

22

203

08-19-1950

8

251

03-31-1960

23

201

09-04-1982

9

241

05-25-1967

24

199

02-07-1946

10

229

07-11-1982

25

199

02-11-1958

11

228

02-07-1986

26

196

05-12-1949

12

226

03-29-1940

26

196

06-04-1991

13

223

08-04-1972

28

195

03-24-1946

14

222

07-05-1941

29

193

05-09-1992

15

221

09-02-1957

30

192

07-14-2000

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