wwrof webinar april 16, 2013 k9la solar topics carl luetzelschwab k9la [email protected] my web site is...
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WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Solar TopicsSolar Topics
Carl Luetzelschwab K9LACarl Luetzelschwab K9LA
[email protected]@arrl.net
my web site is now at http://k9la.us
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
WWROF WebinarsWWROF Webinars Great way to learn about other aspects of Great way to learn about other aspects of
Amateur RadioAmateur Radio Recent onesRecent ones
• The First Top Band DX Contest – the 1921 Transatlantic The First Top Band DX Contest – the 1921 Transatlantic Test (by W3LPL)Test (by W3LPL)
• Overview of Rule Changes for CQ WPX 2013 (by K5ZD)Overview of Rule Changes for CQ WPX 2013 (by K5ZD)• CTU and Dayton Contest Activities (by K3LR) CTU and Dayton Contest Activities (by K3LR)
UpcomingUpcoming• April 26: What I’ve Learned in Two Decades of Terrain April 26: What I’ve Learned in Two Decades of Terrain
Assessment (by N6BV)Assessment (by N6BV) Don’t forget to support WWROFDon’t forget to support WWROF
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
What We’ll CoverWhat We’ll Cover
Cycle 24 updateCycle 24 update Butterfly diagramsButterfly diagrams MagnetogramsMagnetograms Old sunspot dataOld sunspot data Missed an early cycle?Missed an early cycle? Grand solar minimumsGrand solar minimums Max vs previous minMax vs previous min Our Cycle 24 predictionOur Cycle 24 prediction
Two Cycle 24 predictions All the Cycle 24 predictions Hemisphere asymmetry Cycle 24 – two peaks? SSN vs SF vs EUV Are Sunspots Disappearing? Disturbances from the Sun References
Mostly solar topics, with a tiny bit of propagation when relevant
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Cycle 24 UpdateCycle 24 Update
Cycle 24 appears to have had a peak in early 2012
Cycle 24 in terms of 10. 7 cm solar flux
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180
Jan Jul Jan Jul Jan Jul Jan Jul Jan Jan Jul Jan
2009 2010 2011 2012 2013 2014
10
.7 c
m S
ola
r F
lux
monthly mean smoothedMarch 2013latest monthly
September 2012latest smoothed
? ? ?
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Butterfly DiagramsButterfly Diagrams
• Sunspots in a new cycle emerge at higher solar latitudes• Sunspots at the end of a cycle are near the solar equator
note asymmetryHathaway image
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
MagnetogramsMagnetograms Sunspot region has Sunspot region has
magnetic field going out magnetic field going out and coming back inand coming back in
Measure magnetic field Measure magnetic field by Zeeman splittingby Zeeman splitting
By convention, black is By convention, black is “in” and white is “out”“in” and white is “out”
Magnetic fields are Magnetic fields are opposite from one cycle opposite from one cycle to the nextto the next
Magnetic fields are Magnetic fields are opposite in the opposite in the hemisphereshemispheres
solar equator
first sunspot region of Cycle 24
NASA photo
old sunspot region from Cycle 23
Butterfly diagrams and magnetograms allow solar scientists to determine to which cycle (old or new) a sunspot region belongs
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
A Cycle Is Really 22 YearsA Cycle Is Really 22 Years
Cycle 21 max
1976 2012
Hoeksema, Sun, and Hayash image
Cycle 22 max Cycle 23 max
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Cycle 24 - SunspotsCycle 24 - Sunspots
Sunspot data exhibits the same trends as the 10.7 cm solar flux data
Solar Min Between Cycle 23 and 24 and Cycle 24 Ascent(in tems of the sunspot number)
0
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J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N
2006 2007 2008 2009 2010 2011 2012 2013
Su
nsp
ot
Nu
mb
er
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Old Sunspot DataOld Sunspot Data Counting sunspots is subjectiveCounting sunspots is subjective
• Human interpretation involvedHuman interpretation involved Wolf 1849-1893, Wolfer 1876-1928, Brunner Wolf 1849-1893, Wolfer 1876-1928, Brunner
1929-1944, Waldmeier 1945-19951929-1944, Waldmeier 1945-1995
• Capability of telescope and cloud coverCapability of telescope and cloud cover Wolf’s equation: RWolf’s equation: RZZ = k (10G + S) = k (10G + S)
• k is variable to bring different observers in k is variable to bring different observers in line, G is number of groups, S is number of line, G is number of groups, S is number of individual spotsindividual spots
Hoyt and Shatten asked the simple Hoyt and Shatten asked the simple question “How good is the old data?”question “How good is the old data?”
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Group Sunspot NumberGroup Sunspot Number Realizing that counting individual sunspots Realizing that counting individual sunspots
(S) was likely the biggest challenge, they (S) was likely the biggest challenge, they devised the Group Sunspot Numberdevised the Group Sunspot Number
RRGG = k (12G) = k (12G)
The factor “12” scales RThe factor “12” scales RGG to R to RZZ
If you divide RIf you divide RGG by R by RZZ you should get 1.0 you should get 1.0 That’s what they did, and here’s what it That’s what they did, and here’s what it
looks likelooks like
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
RRGG / R / RZZ Uncorrected Uncorrected
RG / RZ less than 1.0 early onTwo discontinuities – around 1946 and 1885It looks like we’ve lived thru the highest solar activity in history
Svalgaard & Cliver image
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Data Under ReviewData Under Review On-going WorkshopsOn-going Workshops
• Sponsored by National Solar Sponsored by National Solar Observatory, the Royal Observatory of Observatory, the Royal Observatory of Belgium, and the Air Force Research Belgium, and the Air Force Research Laboratory Laboratory
Ultimate goal is to review and agree Ultimate goal is to review and agree on the “true” sunspot numberon the “true” sunspot number• Targeted to happen at a Fall 2013 Targeted to happen at a Fall 2013
Workshop in EuropeWorkshop in Europe
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
RRGG / R / RZZ Corrected Corrected
Ratio of RG to RZ varies about 1.0 (can’t do much about the early scatter)Important implication: we’ve NOT lived thru the highest solar activity
Svalgaard & Cliver image
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Did We Miss An Early Cycle?Did We Miss An Early Cycle?
Cycle 4 was Cycle 4 was extremely extremely longlong
1784 – 17981784 – 1798 14 years14 years
How could we have missed a cycle – the data looks very good
Alvestad image
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Problem: Gaps In The DataProblem: Gaps In The Data
Much of the Much of the Cycle 4 data Cycle 4 data was assumedwas assumed
What really What really happened?happened?
Hathaway image
Dalton Min
xxx Min
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Reconstructed Butterfly DiagramReconstructed Butterfly Diagram
Suggests Cycle 4 may have really been only 10 years longSpots from a new cycle may have appeared in 1795/1796
Cycle 4 start
den
sit
y o
f su
nsp
ots
Cycle 5 start
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Auroral ActivityAuroral Activity
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1785
1786
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1797
1798
1799
1800
1801
1802
1803
1804
1805
auro
ras
per
year
year
Indicates an increase in auroral activity around 1796
Cycle 4 start Cycle 5 start
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Missed Cycle - ConclusionMissed Cycle - Conclusion
We may have missed an early cycleWe may have missed an early cycle It was a small one prior to the Dalton It was a small one prior to the Dalton
MinimumMinimum Doesn’t appear to be any discussion Doesn’t appear to be any discussion
to further review and correct thisto further review and correct this• It would be difficult to re-number the It would be difficult to re-number the
cycles after Cycle 4cycles after Cycle 4• If anything is done, best to call it Cycle If anything is done, best to call it Cycle
4a4a
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Grand Solar MinimumsGrand Solar Minimums
No reliable sunspot data from long agoNo reliable sunspot data from long ago Use proxies for solar activityUse proxies for solar activity
• Carbon-14 in tree ringsCarbon-14 in tree rings High carbon-14 means low solar activityHigh carbon-14 means low solar activity Low carbon-14 means high solar activityLow carbon-14 means high solar activity
• Beryllium-10 in ice coresBeryllium-10 in ice cores Identical trends to carbon-14 Identical trends to carbon-14
Gives us a broad view of solar activityGives us a broad view of solar activity
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Inferred Grand MinimumsInferred Grand Minimums
We’ll likely go through another Grand Minimum – questions are “when?” and “what magnitude?”
xxx
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Duration of Solar MinimumDuration of Solar Minimum
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120
1-2
2-3
3-4
4-5
5-6
6-7
7-8
8-9
9-10
10-1
111
-12
12-1
313
-14
14-1
515
-16
16-1
717
-18
18-1
919
-20
20-2
121
-22
22-2
323
-24
sola r m inim um be tw e e n indic a te d c yc le s
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f m
on
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bel
ow
a
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ber
of
20
Cyclic in nature – started with short duration solar mins
recent solar min (56 months)
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Maximum of Solar Cycle Maximum of Solar Cycle
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
solar cycle number
max
imu
m s
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Also cyclic in nature – started with large solar cycles
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Max and Duration of Previous MinMax and Duration of Previous Min
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1201-
22-
33-
44-
55-
66-
77-
88-
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1010
-11
11-1
212
-13
13-1
414
-15
15-1
616
-17
17-1
818
-19
19-2
020
-21
21-2
222
-23
23-2
4
sola r m inim um be tw e e n indic a te d c yc le s
nu
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of
20
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
solar cycle number
max
imu
m s
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ber
They are out of phase
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
The Correlation Suggests . . .The Correlation Suggests . . .Next Solar Max vs Duration of Previous Solar Min
R2 = 0.5815
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10 20 30 40 50 60 70 80 90 100
months at solar minimum (smoothed sunspot number < 20)
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e
Our prediction for Cycle 24 is a smoothed sunspot number of ~ 80Translates to a smoothed 10.7 cm solar flux of ~ 130
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Official Prediction - ISESOfficial Prediction - ISES ISES has not ISES has not
changed their changed their prediction since prediction since mid 2009mid 2009
Prior to mid Prior to mid 2009, they 2009, they carried two carried two predictionspredictions• One high, one One high, one
lowlow
http://www.swpc.noaa.gov/SolarCycle/
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Official Prediction - MSFCOfficial Prediction - MSFC
http://solarscience.msfc.nasa.gov/predict.shtml
MSFC continues to revise its prediction based on actual results
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
A Comment About PredictionsA Comment About Predictions Over 60 Over 60
predictions for predictions for Cycle 24Cycle 24
From 40 to 180 From 40 to 180 (smoothed (smoothed sunspot number)sunspot number)
Several are going Several are going to be “right”to be “right”
Many more will be Many more will be wrongwrong
We still don’t We still don’t understand the understand the process in the Sun process in the Sun that causes solar that causes solar cyclescycles
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Hemisphere AsymmetryHemisphere Asymmetry Sunspot emergence not symmetricalSunspot emergence not symmetrical
The northern hemisphere has dominated Cycle 24The northern hemisphere has dominated Cycle 24
If the southern hemisphere gets going . . . .
Svalgaard & Kamide image
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Cycle 24 – Two Peaks?Cycle 24 – Two Peaks?
Dr. Presnell of the Goddard Space Flight Center Dr. Presnell of the Goddard Space Flight Center believes Cycle 24 will have two peaksbelieves Cycle 24 will have two peaks
Second peak from southern hemisphereSecond peak from southern hemisphere Cites Cycle 14 as similar to Cycle 24Cites Cycle 14 as similar to Cycle 24
http://www.youtube.com/watch?v=6j4bl57D_1U
C yc le 14
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0 20 40 60 80 100
m onths from sta rt
smo
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Great video -
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Recent Two-Peaked CyclesRecent Two-Peaked Cycles
Cycles 19, 20, and 21 didn’t have a discernible second peakCycles 22 and 23 had two peaksReminder – official peak is in terms of a smoothed solar index
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Early Two-Peaked CyclesEarly Two-Peaked Cycles
Would be nice if Cycle 24 did something like Cycle 23 or 12
Cycle 5 Cycle 9
Cycle 11 Cycle 12
Alvestad images
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
SSN vs 10.7 cm SF vs EUVSSN vs 10.7 cm SF vs EUV Reminder – sunspots and 10.7 cm solar flux Reminder – sunspots and 10.7 cm solar flux
are proxies for true ionizing radiationare proxies for true ionizing radiation True ionizing radiation is at wavelengths True ionizing radiation is at wavelengths
from roughly 0.1 – 100 nanometersfrom roughly 0.1 – 100 nanometers• 0.1 – 1 nm and 121.5 nm for the D region0.1 – 1 nm and 121.5 nm for the D region• 1 – 10 nm for the E region1 – 10 nm for the E region• 10 – 100 nm for the F2 region10 – 100 nm for the F2 region
Important wavelength for F2 region Important wavelength for F2 region ionization is around 30 nmionization is around 30 nm• Contributes to about 2/3 of the electron densityContributes to about 2/3 of the electron density
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Daily Values of 26 - 34 nmDaily Values of 26 - 34 nm
correlationsunspots vs EUV .628310.7 cm sf vs EUV .7492
Daily 10.7 cm solar flux correlates better to daily EUV
But don’t throw out sunspots
D aily E U V vs D aily S uns pot Number - November 2001
R 2 = 0.6283
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80
100
120
140
160
2.70
E+
10
2.80
E+
10
2.90
E+
10
3.00
E+
10
3.10
E+
10
3.20
E+
10
da ily E UV (26-34 nm )
dai
ly i
nte
rnati
on
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sun
spo
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um
ber
D aily E U V vs D aily 10.7 c m S olar F lux - November 2001
R 2 = 0.7492
160180200220240260280300
2.70
E+
10
2.80
E+
10
2.90
E+
10
3.00
E+
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3.10
E+
10
3.20
E+
10
da ily E UV (26-34 nm )
dai
ly 1
0.7
cm s
ola
r fl
ux
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Variation of the IonosphereVariation of the Ionosphere
Neither EUV, 10.7 cm solar flux nor sunspots correlate well to the day-to-day variation of the ionosphere
D aily B oulder MU F vs D aily S F - November 2001
R 2 = 0.05232
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45
50
160 180 200 220 240 260 280 300
da ily 10.7 c m soa lr flux
dai
ly M
UF
(19
00 U
TC
)
D aily B oulder MU F vs D aily R - November 2001
R 2 = 0.15301
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35
40
45
50
60 70 80 90 100 110 120 130 140 150 160
da ily inte rna tiona l sunspot num be r
dai
ly M
UF
(19
00 U
TC
)
D aily B oulder MU F vs D aily E U V - November 2001
R 2 = 0.09672
30
35
40
45
50
2.70
E+
10
2.80
E+
10
2.90
E+
10
3.00
E+
10
3.10
E+
10
3.20
E+
10
da ily E UV (26-34 nm )
dai
ly M
UF
(19
00 U
TC
)
F2 region ionization depends on solar radiation, geomagnetic field activity, and events in lower atmosphere coupling up to ionosphere
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Another Interesting CorrelationAnother Interesting CorrelationR 12 vs F 12 F rom 1991 T hru P eak of C yc le 23 (April 2000)
R 2 = 0.995
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250
0 20 40 60 80 100 120 140 160
sm oothe d sunspot num be r R 12
smo
oth
ed 1
0.7
cm s
ola
r fl
ux
F12
Up to the first peak of Cycle 23, smoothed sunspot number and smoothed 10.7 cm solar flux were extremely well correlated
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
But After the Peak . . . But After the Peak . . . R 12 vs F 12 F rom 1991 T hru P res ent
R 2 = 0.9827
0
50
100
150
200
250
0 20 40 60 80 100 120 140 160
sm oothe d sunspot num be r R 12
smo
oth
ed 1
0.7
cm s
ola
r fl
ux
F12
We now see less sunspots for a given 10.7 cm solar flux
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Are Sunspots Disappearing?Are Sunspots Disappearing? July 2009 paper by W. July 2009 paper by W.
Livingston and M. PennLivingston and M. Penn Sunspots are visible Sunspots are visible
when their magnetic when their magnetic field strength is field strength is >> 1500 1500 gaussgauss
Extrapolating the linear Extrapolating the linear trend line says no trend line says no sunspots will be visible sunspots will be visible around the end of the around the end of the decadedecade
Latest data presented Latest data presented by Dr. Leif Svalgaard by Dr. Leif Svalgaard (thru early 2013) (thru early 2013) shows the decreasing shows the decreasing trend is continuingtrend is continuing
most recent data
Livingston & Penn image
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
What’s Happening to EUV?What’s Happening to EUV?
EUV is holding up in spite of sunspots disappearingOther measurements (next slide) confirm this
S moothed Values
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50
100
150
200
250
300
350
0 50 100 150 200 250 300m onths from be g inning of da ta
valu
e
s uns pot num ber 10.7 cm s ola r flux E U V
C yc le 23
C yc le 22
EUV data from www.usc.edu/dept/space_science/semdatafolder/long/daily_avg/
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Other MeasurementsOther Measurements
Why 6m was so good around Nov 2001
This data suggests that sunspots are the only parameter that is disappearing
Lukianova & Mursula images
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Another MinimumAnother Minimum A grand solar minimum
is a period when sunspots disappear
But since it appears that EUV may still be there, maybe a grand solar minimum will not be as bad as we think
This is radical thinking Archibald image
Only answer is to wait and see what happens to EUV with respect to the disappearing sunspots
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Disturbances from the SunDisturbances from the Sun
visit http://www.swpc.noaa.gov/NOAAscales/ to learn more about G, S, and R
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
Mitigation for DisturbancesMitigation for Disturbances
No guarantees here – just suggestions
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
ReferencesReferences The Solar CycleThe Solar Cycle, David H. Hathaway, NASA, Marshall , David H. Hathaway, NASA, Marshall
Space Flight Center, Huntsville, AL, March 2010Space Flight Center, Huntsville, AL, March 2010 A History of Solar Activity over MillenniaA History of Solar Activity over Millennia, Ilya G. , Ilya G.
Usokin, Sodankyla Geophysical Observatory, University of Usokin, Sodankyla Geophysical Observatory, University of Oulu, Finland, October 2008Oulu, Finland, October 2008
Solar Cycle Characteristics Examined in Separate Solar Cycle Characteristics Examined in Separate Hemispheres: Phase, Gnevyshev Gap, and Length of Hemispheres: Phase, Gnevyshev Gap, and Length of MinimumMinimum, A. A. Norton and J. C. Gallagher, James Cook , A. A. Norton and J. C. Gallagher, James Cook University, Townsville, Australia, January 2010 University, Townsville, Australia, January 2010
http://www.solen.info/solar/http://www.solen.info/solar/ http://www.leif.org/research/http://www.leif.org/research/ Temporal Changes in Sunspot Umbral Magnetic Temporal Changes in Sunspot Umbral Magnetic
Fields and TemperaturesFields and Temperatures, M. J. Penn, W. Livingston, , M. J. Penn, W. Livingston, National Solar Observatory, The Astrophysical Journal, 649, National Solar Observatory, The Astrophysical Journal, 649, L45-L48, September 2006L45-L48, September 2006
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
References – con’tReferences – con’t Another Maunder Minimum?Another Maunder Minimum?, Leif Svalgaard, Stanford , Leif Svalgaard, Stanford
University, November 2012University, November 2012 Reconciling Group and International Sunspot Reconciling Group and International Sunspot
NumbersNumbers, Leif Svalgaard, Stanford University, Edward W. , Leif Svalgaard, Stanford University, Edward W. Cliver, Air Force Research Laboratory, September 2012Cliver, Air Force Research Laboratory, September 2012
Disappearance of Visible SpotsDisappearance of Visible Spots, Leif Svalgaard, Stanford , Leif Svalgaard, Stanford University, September 2012University, September 2012
Solar Activity – Past, Present, and FutureSolar Activity – Past, Present, and Future, Leif , Leif Svalgaard, Stanford University, October 2012Svalgaard, Stanford University, October 2012
Symmetric Solar Polar Field ReversalsSymmetric Solar Polar Field Reversals, Leif Svalgaard, , Leif Svalgaard, Stanford Univeristy, Yohsuke Kamide, Nagoya University, Stanford Univeristy, Yohsuke Kamide, Nagoya University, December 2012December 2012
Changed relation between sunspot numbers, solar Changed relation between sunspot numbers, solar UV/EUV radiation and TSI during the declining phase UV/EUV radiation and TSI during the declining phase of solar cycle 23of solar cycle 23, R. Lukianova, K. Mursula, Journal of , R. Lukianova, K. Mursula, Journal of Atmospheric and Solar-terrestrial Physics, 73 (2011), pp Atmospheric and Solar-terrestrial Physics, 73 (2011), pp 235-240235-240
WWROF Webinar April 16, 2013 K9LAWWROF Webinar April 16, 2013 K9LA
SummarySummary
Cycle 24 has a good chance of having a second Cycle 24 has a good chance of having a second peak – will help prolong propagation on the peak – will help prolong propagation on the higher bandshigher bands
Right now the few Cycle 25 predictions are for Right now the few Cycle 25 predictions are for another low solar cycleanother low solar cycle
We’ll enter another grand solar minimum one of We’ll enter another grand solar minimum one of these daysthese days• Don’t know when or magnitudeDon’t know when or magnitude• But it may not result in the demise of the ionosphereBut it may not result in the demise of the ionosphere
Best to use the smoothed 10.7 cm solar flux in Best to use the smoothed 10.7 cm solar flux in your propagation predictionsyour propagation predictions
We covered a lot of material – the following are what I consider important