Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Fri, 19 Apr 91 01:37:49 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 19 Apr 91 01:37:43 -0400 (EDT) Subject: SPACE Digest V13 #425 SPACE Digest Volume 13 : Issue 425 Today's Topics: SOLAR TERRESTRIAL FORECAST AND REVIEW Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: Thu, 18 Apr 91 13:48:33 MDT From: oler <@BITNET.CC.CMU.EDU:oler@HG.ULeth.CA> (CARY OLER) Subject: SOLAR TERRESTRIAL FORECAST AND REVIEW X-St-Vmsmail-To: st%"space+@andrew.cmu.edu" --- SOLAR TERRESTRIAL FORECAST AND REVIEW --- April 18 to April 27, 1991 Report Based In-Part from Data Obtained from the Space Environment Services Center Boulder Colorado -------- SOLAR TERRESTRIAL REVIEW FOR 11 APRIL TO 17 APRIL Solar activity over the past week has been moderate to high. Two major flares highlight the activity. The first occurred at 11:17 UT on 11 April. It attained a class M9.5 x-ray intensity, but was optically uncorrelated due to poor observing conditions at all active observatories. The most likely source of this event was Region 6583, which was exibiting post-flare characteristics after the event. The second major event occurred on 15 April at 09:42 UT. This flare was rated as an M9.8/2F energetic event which was associated with weak to moderate radio bursts, but was not associated with any sweeps. Region 6593 was responsible for this event as it crossed over the eastern limb and into view. Region 6593 has been the most active region on the solar disk thus far. It has produced numerous low-level M-class flares. Region 6583, on the other hand, has been quieter than expected. Region 6583 was the largest region visible during most of the week and exhibited a beta-gamma-delta magnetic configuration with notable optical and magnetic complexity. It has only managed to spawn a few low-level M-class events this week, since the major flare which was suspected of being spawned by this region on 11 April. Late in the period, Region 6580 exploded with growth and apparent complexity. The latest observations now rank this region as being the largest on the disk. It has apparently also established a delta configuration in the spot complex. However, this region is due to rotate behind the western limb and out of view by 20 April. This region could pose a threat for renewed M-class and possible major flare activity when it returns, presently expected sometime near 04 or 05 May. SHORT TERM SOLAR TERRESTRIAL FORECAST Solar activity is expected to continue mostly moderate over the next week, with a fair chance for an isolated major flare from Regions 6580, 6583 or 6593. Solar activity indices have begun to fall back toward the rotational minimum. The minimum for this rotation is expected to reach solar flux values near 180. There is a slight risk for proton activity at geosynchronous satellite altitudes from Region 6583. The risk is small, near about 20% at the present time, but is worthy of note. Geomagnetic activity is expected to remain generally unsettled over the coming week. Activity is expected to become enhanced, particularly over the high latitudes, on or near 25 to 27 April. The recurrent activity should keep high latitudes at generally active levels until 28 or 29 April when a decline to more unsettled conditions are expected. Middle and low latitudes should mantain generally unsettled conditions throughout this period. Auroral activity is not expected to become unusually active over the coming week. It is expected to become somewhat enhanced over the northerly middle and high latitudes (particularly over the high latitude regions) on 26 or 27 April, returning to more dormant levels on or near 29/30 April. In the meantime, high latitudes should maintain generally low auroral activity possibly intermixed with isolated periods of moderate auroral activity. Middle latitude auroral activity will remain generally dormant. Northerly middle latitudes will probably be able to witness low levels of auroral activity on the horizon, particularly on 26/27 April, if the recurrent activity materializes as expected. HF propagation conditions are expected to remain normal to above normal throughout the coming week. A decline in solar activity should produce slightly lower MUF's, although overall, MUF's should still remain well above 30 MHz. Some SWF's can be expected throughout the week, due to occassional M-class flaring from Regions 6583 and 6593. No significant degradations are expected over the low and middle latitudes. Some degradation is likely over the high latitudes due to recurrent geomagnetic and auroral activity. Conditions are expected to vary from fair to poor throughout the coming week. High latitude conditions should improve somewhat after 28/29 April. VHF propagation conditions are expected to remain normal throughout the coming week. No significant DX is expected on the VHF bands this coming week. There is a chance for brief isolated periods of VHF SID-induced enhancements caused by minor flaring, although even these will likely be difficult to catch. No significant auroral backscatter is expected this week, barring possible major solar activity. High latitudes will have the best possibilities for experiencing VHF auroral backscatter communications. SUMMARY OF ALL ACTIVE REGIONS VISIBLE ON THE SOLAR DISK AS OF 18 APRIL Region # Location LO Area Class LL Spots Magnetic Type -------- -------- --- ---- ----- -- ----- ------------- 6580 N29W61 284 1890 DKI 07 015 BETA DELTA 6582 S24W37 260 0480 CAO 12 010 BETA 6583 N09W18 241 1380 EKI 14 073 BETA GAMMA 6587 S27W07 230 0000 AXX 01 002 ALPHA 6592 N14E10 213 0210 CAO 06 018 BETA 6593 S08E32 191 1080 EKO 15 033 BETA GAMMA 6594 S19W20 243 0090 CAO 08 013 BETA 6596 S22E45 178 0030 BXO 04 002 BETA 6598 S08E16 207 0060 BXO 07 011 BETA NOTES: Area is in million square kilometers. Angular extent (LL) and solar longitude (LO) are in degree's. For more information regarding the terminology used above, request the Glossary of Solar Terrestrial Terms from: "oler@hg.uleth.ca". H-ALPHA PLAGES WITHOUT SPOTS. LOCATIONS VALID AS OF 00:00 UT ON 18 APRIL REGION LOCATION LO COMMENTS (IF ANY) ------ -------- --- ------------------------------- 6579 N07W88 311 NONE 6581 N14W44 267 6588 S02W80 303 6589 S12W66 289 6590 S15W56 279 6591 N09W40 263 6595 S31E31 192 6597 S22E46 177 ACTIVE REGIONS DUE TO RETURN BETWEEN 18 APRIL AND 20 APRIL Region Latitude Longitude (Helio.) ------ -------- --------- NO REGIONS DUE TO RETURN NOTES: For definitions regarding the above, request the "Glossary of Solar Terrestrial Terms" from "oler@hg.uleth.ca". GRAPHICAL ANALYSIS OF RECENT PLANETARY (GLOBAL) GEOMAGNETIC ACTIVITY Cumulative Geomagnetic Activity History Peak Planetary Geomagnetic Activity during the past 96 hours ____________________________________________________________________ | EXTREMELY SEVERE | | | | | HIGH | | VERY SEVERE STORM | | | | | HIGH | | SEVERE STORM | | | | | MODERATE | | MAJOR STORM | | | | | LOW - MOD. | | MINOR STORM | | | | | LOW | | VERY ACTIVE | | | | * | NONE | | ACTIVE | ** | ** | *** | * *** | NONE | | UNSETTLED | ******| *****| *****|********| NONE | | QUIET |********|********|* ******|********| NONE | | VERY QUIET |********|********|********|********| NONE | |-------------------|--------|--------|--------|--------|------------| | Geomagnetic Field | Sun. | Mon. | Tue. | Wed. | Anomaly | | Conditions | Given in 3-hourly UT intervals | Intensity | |____________________________________________________________________| NOTES: The data above represents preliminary planetary geomagnetic activity. Data from many magnetic observatories around the world are used in constructing the above chart. The first graph line for each day represents geomagnetic activity which occurred between 00 UT and 03 UT. The second graph line represents activity which occurred between 03 UT and 06 UT, etc. For information regarding the interpretation and/or use of these charts, send a request for the document "Understanding Solar Terrestrial Reports" to: oler@hg.uleth.ca. PLANETARY 10-DAY GEOMAGNETIC ACTIVITY OUTLOOK (18 APRIL - 27 APRIL) ________________________________________________________________________ | EXTREMELY SEVERE | | | | | | | | | | | HIGH | | VERY SEVERE STORM | | | | | | | | | | | HIGH | | SEVERE STORM | | | | | | | | | | | MODERATE | | MAJOR STORM | | | | | | | | | | | LOW - MOD. | | MINOR STORM | | | | | | | | | | | LOW | | VERY ACTIVE | | | | | | | | | | | NONE | | ACTIVE | * | | | | | | | | | * | NONE | | UNSETTLED |***|** | * |** |** |** |** |** |***|***| NONE | | QUIET |***|***|***|***|***|***|***|***|***|***| NONE | | VERY QUIET |***|***|***|***|***|***|***|***|***|***| NONE | |-------------------|---|---|---|---|---|---|---|---|---|---|------------| | Geomagnetic Field |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| Anomaly | | Conditions | Given in 8-hour intervals | Intensity | |________________________________________________________________________| CONFIDENCE LEVEL: 75% NOTES: Predicted geomagnetic activity is based heavily on recurrent phenomena. Transient energetic solar events cannot be predicted reliably over periods in excess of several days. Hence, there may be some deviations from the predictions due to the unpredictable transient solar component. GRAPHICAL ANALYSIS OF SOLAR ACTIVITY OVER THE PAST 60 DAYS Cumulative Graphical Analysis of Solar Activity ____________________________________________________________ 311| * | HIGH 301| ****F F = Major Flare(s) | HIGH 291| ****F | HIGH 281| *****F | HIGH 271| *****F* F | HIGH 261| *******F* FF *F* | HIGH 251| *******F** F FF FF * * *F**| HIGH 242| *******F** F*FFFFFFF * ***F**| Moderate 232| *******F*** F FF*FFFFFFFF*F F***F**| Moderate 222| *******F*** F **FFF*FFFFFFFF*FF *F***F**| Moderate 212|********F**** FF FF***FFF*FFFFFFFF*FF *F***F**| Moderate 202|********F******FF*FF***FFF*FFFFFFFF*FF* **F***F**| Moderate 192|********F******FF*FF***FFF*FFFFFFFF*FF** *F* ***** **F***F**| Moderate 182|********F******FF*FF***FFF*FFFFFFFF*FF**F*F*F********F***F**| Low ------------------------------------------------------------ Cumulative 60 day Solar Activity Record Start Date: February 17, 1990 NOTES: Left-hand column digits represent the 10.7 cm solar radio flux obtained from Ottawa. The right-hand column describes the relative solar activity for that period based on the average number of major and minor flares that can be expected for related solar flux values. Plot lines labeled with the letter "F" represent days where at least one major flare occurred (ie. class M5 or greater flare). GRAPHICAL 20-DAY SOLAR ACTIVITY PREDICTION Solar Activity _________________________________________________________________ | 260 | | | | | | | | | | | | | | | | | | | | | | 253 | | | | | | | | | | | | | | | | | | | | | | 245 | | | | | | | | | | | | | | | | | | | |**| | 238 | | | | | | | | | | | | | | | | | | | | | | 231 |**| | | | | | | | | | | | | | | | | |**| | | 223 | |**| | | | | | | | | | | | | | | |**| | | | 216 | | |**| | | | | | | | | | | | | | | | | | | 209 | | | |**| | | | | | | | | | | | |**| | | | | 202 | | | | |**| | | | | | | | | | | | | | | | | 194 | | | | | |**|**|**| | | | | | | | | | | | | | 187 | | | | | | | | |**| | | | | | |**| | | | | | 180 | | | | | | | | | |**|**| | | |**| | | | | | | 172 | | | | | | | | | | | |**|**|**| | | | | | | |-----|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--| |Solar|18|19|20|21|22|23|24|25|26|27|28|29|30|01|02|03|04|05|06|07| |Flux | April | May | ----------------------------------------------------------------- CONFIDENCE LEVEL: 65% HF RADIO SIGNAL PROPAGATION PREDICTIONS (18 APRIL - 27 APRIL) High Latitude Paths ________________________________________________________ | EXTREMELY GOOD | | | | | | | | | | | | VERY GOOD | | | | | | | | | | | CONFIDENCE | GOOD | | | | | | | | | | | LEVEL | FAIR |* *|* *|***|***|***|***|* *| *| *| *| ------- | POOR | * | * | | | | | * |** |** |** | 70% | VERY POOR | | | | | | | | | | | | EXTREMELY POOR | | | | | | | | | | | |----------------|---|---|---|---|---|---|---|---|---|---| | PROPAGATION |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| | QUALITY | Given in 8-Hour UT Intervals | -------------------------------------------------------- Middle Latitude Paths ________________________________________________________ | EXTREMELY GOOD | | | | | | | | | | | | VERY GOOD | | | | *|* *|* *| | | | | CONFIDENCE | GOOD |***|***|***|** | * | * |***|***|* *|* *| LEVEL | FAIR | | | | | | | | | * | * | ------- | POOR | | | | | | | | | | | 70% | VERY POOR | | | | | | | | | | | | EXTREMELY POOR | | | | | | | | | | | |----------------|---|---|---|---|---|---|---|---|---|---| | PROPAGATION |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| | QUALITY | Given in 8-Hour UT Intervals | -------------------------------------------------------- Low Latitude Paths ________________________________________________________ | EXTREMELY GOOD | | | | | | | | | | | | VERY GOOD | | | | *|* *|* *|* *| | | | CONFIDENCE | GOOD |***|***|***|** | * | * | * |***|***|***| LEVEL | FAIR | | | | | | | | | | | ------- | POOR | | | | | | | | | | | 70% | VERY POOR | | | | | | | | | | | | EXTREMELY POOR | | | | | | | | | | | |----------------|---|---|---|---|---|---|---|---|---|---| | PROPAGATION |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| | QUALITY | Given in 8-Hour UT Intervals | -------------------------------------------------------- NOTES: NORTHERN HEMISPHERE SOUTHERN HEMISPHERE High latitudes >= 55 deg. N. | High latitudes >= 55 deg. S. Middle latitudes >= 40 < 55 deg. N. | Middle latitudes >= 35 < 55 deg. S. Low latitudes < 40 deg. N. | Low latitudes < 35 deg. S. POTENTIAL VHF DX PROPAGATION PREDICTIONS (18 APRIL - 27 APRIL) INCLUDES SID AND AURORAL BACKSCATTER ENHANCEMENT PREDICTIONS HIGH LATITUDES __________________________________________________ ___________________ | SIGNAL | Given in 8 hour local time intervals | | SID ENHANCEMENT | | QUALITY |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| |S|M|T|W|T|F|S|S|M|T| |__________|___|___|___|___|___|___|___|___|___|___| |-|-|-|-|-|-|-|-|-|-| | VERY GOOD| | | | | | | | | | | 0%|*|*|*|*|*|*|*|*|*|*| |ABOVE NORM| | | | | | | | | | | 20%|*|*|*|*|*|*|*|*|*|*| | NORMAL| **|***|***| **| **|***| **| **| * | * | 40%|*|*|*|*|*|*|*|*|*|*| |BELOW NORM|* | | |* |* | |* |* |* *|* *| 60%| | | | | | | | | | | | VERY POOR| | | | | | | | | | | 80%| | | | | | | | | | | | BLACKOUT| | | | | | | | | | |100%| | | | | | | | | | | |==========|===|===|===|===|===|===|===|===|===|===| |-------------------| | 100% | | | | | | | | | | |100%| | | | | | | | | | | | 80% | | | | | | | | | | | 80%| | | | | | | | | | | | 60% | | | | | | | | | *|* *| 60%| | | | | | | | | |*| | 40% | *| | |* *|* *|* |* |* *|* *|* *| 40%| | | |*|*| |*| |*|*| | 20% |***|***|***|***|***|***|***|***|***|***| 20%|*|*|*|*|*|*|*|*|*|*| | 0% |***|***|***|***|***|***|***|***|***|***| 0%|*|*|*|*|*|*|*|*|*|*| |----------+---|---|---|---|---|---|---|---|---|---| |-|-|-|-|-|-|-|-|-|-| |CHANCE OF |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| |T|F|S|S|M|T|W|T|F|S| | VHF DX | Given in 8 hour local time intervals | |AURORAL BACKSCATTER| |__________|_______________________________________| |___________________| MIDDLE LATITUDES __________________________________________________ ___________________ | SIGNAL | Given in 8 hour local time intervals | | SID ENHANCEMENT | | QUALITY |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| |S|M|T|W|T|F|S|S|M|T| |__________|___|___|___|___|___|___|___|___|___|___| |-|-|-|-|-|-|-|-|-|-| | VERY GOOD| | | | | | | | | | | 0%|*|*|*|*|*|*|*|*|*|*| |ABOVE NORM| | | | | | | | | | | 20%|*|*|*|*|*|*|*|*|*|*| | NORMAL|***|***|***|***|***|***|***|***|***| **| 40%|*|*|*|*|*|*|*|*|*|*| |BELOW NORM| | | | | | | | | |* | 60%| | | | | | | | | | | | VERY POOR| | | | | | | | | | | 80%| | | | | | | | | | | | BLACKOUT| | | | | | | | | | |100%| | | | | | | | | | | |==========|===|===|===|===|===|===|===|===|===|===| |-------------------| | 100% | | | | | | | | | | |100%| | | | | | | | | | | | 80% | | | | | | | | | | | 80%| | | | | | | | | | | | 60% | | | | | | | | | | | 60%| | | | | | | | | | | | 40% | * | * | * | * | * | * | * | * | **| **| 40%| | | | | | | | | | | | 20% | **| **| **|***|***|***| **| **|***|***| 20%| | | |*|*| | | |*|*| | 0% |***|***|***|***|***|***|***|***|***|***| 0%|*|*|*|*|*|*|*|*|*|*| |----------+---|---|---|---|---|---|---|---|---|---| |-|-|-|-|-|-|-|-|-|-| |CHANCE OF |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| |T|F|S|S|M|T|W|T|F|S| | VHF DX | Given in 8 hour local time intervals | |AURORAL BACKSCATTER| |__________|_______________________________________| |___________________| LOW LATITUDES __________________________________________________ ___________________ | SIGNAL | Given in 8 hour local time intervals | | SID ENHANCEMENT | | QUALITY |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| |S|M|T|W|T|F|S|S|M|T| |__________|___|___|___|___|___|___|___|___|___|___| |-|-|-|-|-|-|-|-|-|-| | VERY GOOD| | | | | | | | | | | 0%|*|*|*|*|*|*|*|*|*|*| |ABOVE NORM| | | | | | | | | | | 20%|*|*|*|*|*|*|*|*|*|*| | NORMAL|***|***|***|***|***|***|***|***|***|***| 40%|*|*|*|*|*|*|*|*|*|*| |BELOW NORM| | | | | | | | | | | 60%| | | | | | | | | | | | VERY POOR| | | | | | | | | | | 80%| | | | | | | | | | | | BLACKOUT| | | | | | | | | | |100%| | | | | | | | | | | |==========|===|===|===|===|===|===|===|===|===|===| |-------------------| | 100% | | | | | | | | | | |100%| | | | | | | | | | | | 80% | | | | | | | | | | | 80%| | | | | | | | | | | | 60% | | | | | | | | | | | 60%| | | | | | | | | | | | 40% | * | * | * | * | * | * | * | * | * | * | 40%| | | | | | | | | | | | 20% | **| **| **| **| **| **| **| **| **|***| 20%| | | | | | | | | | | | 0% |***|***|***|***|***|***|***|***|***|***| 0%|*|*|*|*|*|*|*|*|*|*| |----------+---|---|---|---|---|---|---|---|---|---| |-|-|-|-|-|-|-|-|-|-| |CHANCE OF |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| |T|F|S|S|M|T|W|T|F|S| | VHF DX | Given in 8 hour local time intervals | |AURORAL BACKSCATTER| |__________|_______________________________________| |___________________| NOTES: These VHF DX prediction charts are defined for the 50 MHz to 220 MHz bands. They are based primarily on phenomena which can affect VHF DX propagation globally. They should be used only as a guide to potential DX conditions on VHF bands. Latitudinal boundaries are the same as those for the HF predictions charts. For more information, request the document "Understanding Solar Terrestrial Reports" from: "oler@hg.uleth.ca". AURORAL ACTIVITY PREDICTIONS (18 APRIL - 27 APRIL) High Latitude Locations ________________________________________________________ | EXTREMELY HIGH | | | | | | | | | | | CONFIDENCE | VERY HIGH | | | | | | | | | | | LEVEL | HIGH | | | | | | | | | | | ------- | MODERATE | | | | * | * | | | * |***|***| 70% | LOW |***|***|***|***|***|***|***|***|***|***| | NOT VISIBLE |***|***|***|***|***|***|***|***|***|***| |----------------|---|---|---|---|---|---|---|---|---|---| | AURORAL |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| | INTENSITY | Eve.Twilight/Midnight/Morn.Twilight | -------------------------------------------------------- Middle Latitude Locations ________________________________________________________ | EXTREMELY HIGH | | | | | | | | | | | CONFIDENCE | VERY HIGH | | | | | | | | | | | LEVEL | HIGH | | | | | | | | | | | ------- | MODERATE | | | | | | | | | | | 70% | LOW | | | | * | * | | | | * |***| | NOT VISIBLE |***|***|***|***|***|***|***|***|***|***| |----------------|---|---|---|---|---|---|---|---|---|---| | AURORAL |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| | INTENSITY | Eve.Twilight/Midnight/Morn.Twilight | -------------------------------------------------------- Low Latitude Locations ________________________________________________________ | EXTREMELY HIGH | | | | | | | | | | | CONFIDENCE | VERY HIGH | | | | | | | | | | | LEVEL | HIGH | | | | | | | | | | | ------- | MODERATE | | | | | | | | | | | 85% | LOW | | | | | | | | | | | | NOT VISIBLE |***|***|***|***|***|***|***|***|***|***| |----------------|---|---|---|---|---|---|---|---|---|---| | AURORAL |Thu|Fri|Sat|Sun|Mon|Tue|Wed|Thu|Fri|Sat| | INTENSITY | Eve.Twilight/Midnight/Morn.Twilight | -------------------------------------------------------- NOTE: For more information regarding these charts, send a request for the document, "Understanding Solar Terrestrial Reports" to: oler@hg.uleth.ca. ** End of Report ** ------------------------------ End of SPACE Digest V13 #425 *******************