Transcript Solar Cycle 24 and 10

Solar Cycle 24
Carl Luetzelschwab K9LA
[email protected]
QCWA Chap 36 April 2012 K9LA
What We’re Going to Cover
•
•
•
•
Recent solar minimum
Predictions for Cycle 24
Cycle 24 status
Four FAQs
QCWA Chap 36 April 2012 K9LA
Recent Solar Minimum
22
between Cycles 18 and 19
(min Apr 1954)
smoothed sunspot number
20
18
16
between Cycles 19 and 20
(min Nov 1964)
14
12
between Cycles 20 and 21
(min Jun 1976)
10
8
between Cycles 21 and 22
(min Sep 1986)
6
between Cycles 22 and 23
(min Oct 1996)
4
2
between Cycles 23 and 24
(min Dec 2008)
0
1
6
11
16
21
26
31
36
41
46
51
56
months from descent below a smoothed
sunspot number of 20
Minimum between Cycle 23 and
24 very unusual for our lifetimes
QCWA Chap 36 April 2012 K9LA
All Solar Minimum Periods
120
80
60
40
20
0
1-2
2-3
3-4
4-5
5-6
6-7
7-8
8-9
9-10
10-11
11-12
12-13
13-14
14-15
15-16
16-17
17-18
18-19
19-20
20-21
21-22
22-23
23-24
num ber of m onths below
a s m oothed s uns pot
num ber of 20
100
sola r m inim um be tw e e n indic a te d c yc le s
• But not all that unusual for all 23 solar minimum periods
• Note cyclic nature of data
QCWA Chap 36 April 2012 K9LA
All Solar Maximums
250
Average ~ 115
maximum smoothed
sunspot number
200
150
100
50
0
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
• Note cyclic nature of this data, too
• Is there a correlation between duration of solar min and next
max?
QCWA Chap 36 April 2012 K9LA
Next Max vs Previous Min
Next Solar Max vs Duration of Previous Solar Min
maximum
smoothed sunspot
number of next
solar cycle
250
R2 = 0.5815
200
150
100
50
0
10
20
30
40
50
60
70
80
90
100
months at solar minimum (smoothed sunspot number < 20)
• Suggests Cycle 24 will be below average
– 56 months (from previous slide) = 85
• And maybe the next couple cycles, too
QCWA Chap 36 April 2012 K9LA
Latest Prediction from MSFC
• Nominal max of 61
• Uncertainty in
prediction puts high
side at 87
MSFC is the Marshall Space Flight Center in Huntsville, AL
[ http://solarscience.msfc.nasa.gov/predict.shtml ]
QCWA Chap 36 April 2012 K9LA
Latest Predictions from ISES
Don’t forget that the sunspot number and 10.7 cm solar flux are proxies for the true ionizing radiation
in terms of sunspot number
in terms of 10.7 cm solar flux
ISES is the International Space Environment Service – a
service used by the Space Weather Prediction Center of
NOAA [http://www.swpc.noaa.gov/SolarCycle/ ]
QCWA Chap 36 April 2012 K9LA
Latest Data for Cycle 24
•
•
•
The recent slowdown in the smoothed sunspot number may just be a
normal “leveling off” as seen in other cycles
April monthly mean is likely to be higher than March monthly mean
Expect the smoothed sunspot number to again increase
QCWA Chap 36 April 2012 K9LA
When Are The Higher Bands Open?
• 15-Meters: F2 when the smoothed sunspot number > 25
– We’re already there
• 12-Meters: F2 when the smoothed sunspot number > 35
– We’re already there
• 10-Meters: F2 when the smoothed sunspot number > 50
– We’re right on the border for consistent worldwide openings
QCWA Chap 36 April 2012 K9LA
Four FAQs
• Is Cycle 24 going to have two peaks?
• Is Cycle 24 going to offer any 6-Meter F2
propagation?
• Are sunspots disappearing?
• Are we headed for another Maunder
Minimum?
QCWA Chap 36 April 2012 K9LA
Two Peaks?
• Cycle 19, 20, and 21
didn’t show much of a
second peak
• Cycle 22 and 23 did
show a definite
second peak
– Cycle 23’s second peak
made 6-Meter DXers
very happy in the
Winter of 2001
Cycle 24 has a decent
chance of a second peak
QCWA Chap 36 April 2012 K9LA
Any 6-Meter F2 Propagation?
• Not very likely (extremely low probability) with the
current Cycle 24 prediction
• If F2 does happen, it would be most likely during the
Spring, Fall, and Winter of 2013
• To reiterate, Sporadic E should still be there
– Late morning and early evening in the Summer
– Early evening in December
QCWA Chap 36 April 2012 K9LA
Are Sunspots Disappearing?
• W. Livingston and M. Penn
measured the maximum
strength of magnetic fields of
sunspots
• Strength has been declining
since 1992
• Need about 1500 gauss for
sunspots to be visible
• Extrapolating their data says
sunspots will disappear by 2015
• 2012 update – declining trend
continues thru 2011
Remember that sunspots are a proxy
for the true ionizing radiation (EUV),
which still appears to be alive and well
QCWA Chap 36 April 2012 K9LA
Another Maunder Minimum?
• Maunder Minimum was a lack of sunspots from 1645-1715
• Cycles -11, -10, and -9 showed a smooth decrease in group
sunspot number leading up to the Maunder Minimum
– 125, 40, 20
• It’s generally agreed that the Sun is “slowing down”
• Cycles 22, 23, and 24 exhibit a smooth decrease, too
– 158, 121, around 60 to 90
• Where Cycle 24 ends up and the solar minimum between
Cycle 24 and 25 will be interesting, and may suggest where
we’re headed
QCWA Chap 36 April 2012 K9LA
Summary
• Cycle 24 maximum expected in early or mid
2013
• Cycle 24 expected to be below average
• 15-Meters, 12-Meters, and 10-Meters are
good now, so take advantage of them
• Have fun!
QCWA Chap 36 April 2012 K9LA