Solar and Anthropogenic
Impacts on Earth:
The Current Solar Minimum and
Predictions for Future Decades
Workshop Introduction
Tom Woods
LASP / University of Colorado
tom.woods@lasp.colorado.edu
Workshop Organizers
Bob Cahalan, Greg Kopp, Judith Lean,
Peter Pilewskie, Tom Woods, Vanessa George
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Low Cycle Minimum is April Fool’s Joke
two years in a row
•  From AGU SPA Section newsletter 1-April-2010:
Nomenclature Committee Report
From: B. McPherron <claruse at igpp.ucla.edu>
To the relief of many in the SPA community solar activity is on the rise once again,
signaling the end to the longest and deepest solar minimum since the Dalton
minimum 200 years ago. Seizing the opportunity to get recognition for senior
members of the SPA section, Dr. Blob McPherron asked the SPA Nomenclature
Committee to decide which of the many eligible senior SPA scientists would
receive the honor of having their name attached to this extraordinary minimum.
The two most obvious choices,based on their recent letters to EOS, were R.
Mendillo and A.F.T. Stern, who made references to their multiple solar-cycle career
ages and their dismay at their lack of appreciation by younger peers. After several
ballots, perhaps because of his longer tenure in the field, or perhaps because of
his deeper dismay, Stern was selected. The SPA Executive committee has now
approved this designation and requested that henceforth the community refer to
the cycle 23/24 minimum as the Stern minimum. The Nomenclature Committee
has returned to the choosing names for the three phases of a substorm, which,
after 30 years of discussion, they are close to resolving. The new names will be
announced as soon as agreement is reached on the timing of each phase.
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SORCE: A Mission of Solar Irradiance for Climate Research
•  SORCE Measurements
–  Total Solar Irradiance (TSI)
–  Solar Spectral Irradiance (SSI)
•  0.1-27 nm and 115-2400 nm
–  Daily cadence for data products
•  Relations to Earth Science Research
–  Critical measurement for solar forcing of
climate change
–  Important measurements for radiative forcing,
dynamics, and photochemistry for atmospheric
studies
•  SORCE Mission
–  Launched January 25, 2003; now in extended
mission for 8th year
–  Instruments are in excellent condition
–  Spacecraft has limited-life components (battery
and reaction wheels), but expect to have
overlap with Glory TIM and maybe NOAA TSIS
http://lasp.colorado.edu/sorce/
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Key Questions for Workshop
•  Are spectral and total solar irradiance levels lower now
than during past minima, and how much will they
increase during solar cycle 24?
•  Are we entering a new prolonged period of anomalously
low activity such as the Dalton Minimum in the early
1800s?
•
If so, should this cycle 23/24 minimum have a name? (e.g., Eddy Minimum)
•  Can we identity anomalous behavior in the solar dynamo
and surface flux transport during the current minimum?
•  How are heliospheric changes altering incident cosmic
ray fluxes and the Earth’s near-space environment?
•  Can we reliably discern the terrestrial signatures of the
current solar inactivity – at the surface, in the
stratosphere, and in space weather?
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1. Total Solar Irradiance (TSI): Comparison of Solar
Cycle Minima and Recent Validation Results
•  Is the TSI lower in 2008 than in 1996?
–  If so, what are the consequences on climate change?
–  Session 2: Climate Changes: What’s the Future Going To Be?
•  Is there improved closure on the TSI difference?
300-1000 ppm stated accuracy
but
±3000 ppm differences
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3. Solar Spectral Irradiance (SSI):
Solar Cycle Variation and Model Comparisons
•  How do models compare to SIM’s variability that is out of
phase with solar cycle at some wavelengths?
•  Is the SSI lower in 2008 than in 1996?
SOHO SEM EUV Irradiance
Long-term Precision
versus
Instrument Trends
From Leonid Didkovsky
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4. Atmosphere and Ozone Changes:
Has the Ozone Recovery Started Yet?
•  Has the ozone recovery started yet?
•  Is the SIM solar cycle variability seen in the ozone?
Expect Larger Ozone Changes
for SIM Larger UV Variability
From Jerry Harder
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5. Space Weather Effects Observed
During This Solar Cycle Minimum
•  What are the consequences of the more abundant lowlatitude coronal holes on the Sun?
•  Are there detectable changes in Earth’s upper
atmosphere during this cycle minimum?
–  Expect cooler and less dense thermosphere / ionosphere
–  Are these changes just due to more anthropogenic CO2?
Solar Driven
or
Anthropogenic CO2 Effect ?
Density Result
from
Satellite Drag
data analysis
From John Emmert
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6. Solar Physics: What Do We Learn About
the Sun from this Unique Cycle Minimum?
•  What do we learn about the solar dynamo from this
unique cycle minimum?
–  What are the predictions for the next cycle maximum?
•  What are the consequences for lower magnetic flux?
Why is the polar
magnetic flux lower?
From Wilcox Solar Observatory
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7. Recommendations for the Future:
How to Improve the Climate Data Record?
•  What are the future research / mission opportunities?
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Workshop Logistics
•  Oral Presenters
–  PC / Mac available: Office / Acrobat / Keynote (Mac only)
–  Provide presentation in advance (during breaks)
•  Poster Session on Wednesday 4:30 – 6:30 PM with Reception
–  4’ x 6’ (1.2 m x 1.8 m) area assigned per poster
–  Posters are up all week
•  Need Help?
–  Vanessa George can help with registration, hotel, and local questions
–  Workshop Organizers: Bob Cahalan, Greg Kopp, Judith Lean, Peter
Pilewskie, Tom Woods, and Vanessa George
–  Poster Organizer: Marty Snow
•  Group Meals
–  Lunches provided Wednesday and Thursday
–  Dinner party Thursday evening at 6:30 PM - $50
•  Buses leave at 5:50 and 6:15 PM from Keystone Lodge parking circle
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