Discerning the role of the Sun in climate variations on time scales of decades is a challenging task. Climate forcing is well correlated with variations in the Sun’s energy output. This is well established for total and UV irradiance using high-precision, space-based solar measurements spanning more than two decades. When the Sun is near the maximum of its activity cycle, it is about 0.1% brighter overall, with much greater changes at UV wavelengths. SORCE and other missions measure these variations of the total solar irradiance (TSI) and solar spectral irradiance (SSI) with unprecedented accuracy, precision, and spectral coverage across the UV, visible, and IR.
Widespread empirical evidence from the extensive Earth climate datasets suggests the presence of an 11-year solar signal of order 0.1K in surface, atmospheric, and ocean temperatures. The solar forcing processes and pathways can be complex though. For example, the top-down pathway considers solar variations in the UV spectrum modulating stratospheric ozone concentrations, which then couple down to climate change via radiative and dynamical pathways. Internal atmosphere-ocean oscillations such as the NAO and ENSO may also play a role. Clouds may expedite the process via feedbacks, which require modeling very complex interactions.
We seek new understanding of the evidence for and mechanisms involved in decadal variability in the Sun and climate. The 2014 SORCE Science Meeting will review what we have learned in the past 11 years during the SORCE mission.
Sessions are organized around the following key questions:
- How much have the TSI and SSI varied over the SORCE mission, starting near maximum for solar cycle 23 and currently near maximum for cycle 24?
- What has been learned from connecting the SORCE TSI and SSI measurements to the long-term TSI and SSI records?
- What has been learned from comparing TSI and SSI measurements to solar proxies and irradiance model predictions?
- How have Earth’s atmosphere and climate changed over the SORCE mission?
- What are the dominant processes and pathways for solar forcing in Earth’s environment?
- How have the extended cycle minimum in 2007-2009 and lower cycle 24 maximum affected climate differently than during the earlier solar cycle 23?
- How can these Sun-climate results be effectively applied for reconstructions to the past and for future climate change predictions?
- What are the key science results and lessons learned from the SORCE mission?
- How will the TSI, SSI, and Sun-climate records continue in the future?
- Role of the Sun in Climate Change during the SORCE Mission
What have we learned about the Sun’s influence on the atmosphere during the SORCE mission? What is the Sun’s role in recent “Global Warming Hiatus”? In particular, how has the atmosphere and climate responded over the past decade? Are there discernible trends in critical upper atmospheric monitors such as ozone, temperature, and other trace species? How well are models able to capture these trends and how well do they reproduce the current observation sets? What is the current status of critical climatic monitors such as sea ice loss and changes in polar and mid-latitude glaciation?
- Solar Spectral Irradiance (SSI) Measurements
Discussion of the current set of SSI measurements including laboratory calibration and on-orbit corrections. Comparison of currently-operating missions with an emphasis on the SORCE mission timeframe will also be solicited.
- Solar Spectral Irradiance (SSI) Composites, Proxies, Models
Discussion of composite data records for both TSI and SSI that extend beyond the SORCE mission. Solar irradiance model results and solar irradiance proxy measurements will also be invited. In particular, discussion of solar models that have been developed or refined based on SORCE data will be highly desired.
- Total Solar Irradiance (TSI) Measurements and Composites
What have we learned about the Sun’s influence on the atmosphere during the SORCE mission? What is the Sun’s role in recent “Global Warming Hiatus”? In particular, how has the atmosphere and climate responded over the past decade? Are there discernible trends in critical upper atmospheric monitors such as ozone, temperature, and other trace species? How well are models able to capture these trends and how well do they reproduce the current observation sets? What is the current status of critical climatic monitors such as sea ice loss and changes in polar and mid-latitude glaciation?Discussion of the current set of TSI measurements including recent laboratory calibrations and efforts to improve the 35-year spaceborne data record’s accuracy and stability via instrument teams’ efforts and inter-team collaborations.
- Decadal and Longer Sun-Climate Variations
This session will focus on long-term solar irradiance estimates. Time scales of interest range from centuries to millennia, all they way to the early Sun. Contributions regarding the solar influence on paleoclimate are also solicited.
- Legacy of SORCE and Future Directions after SORCE
This session could include lessons learned from the SORCE instruments as well as future atmospheric and climate modeling efforts. How has SORCE impacted the study of the Sun-Earth connection?
This meeting is sponsored by the Solar Radiation and Climate Experiment (SORCE) Science Team at the Laboratory for Atmospheric and Space Physics, University of Colorado. Since its launch in January 2003, SORCE has been measuring total solar irradiance (TSI) and solar spectral irradiance (SSI), which are part of NASA Earth Observing System’s 24 key observables. These annual SORCE Science Meetings bring together interested members of the broad solar and climate communities to discuss current understanding of solar variability and the Sun’s influence on climate and global change.
If you have any questions regarding the science program, please contact one of the 2014 SORCE Meeting Organizing Committee members.
2014 SORCE Science Meeting Organizing Committee:
- Robert Cahalan – Robert.F.Cahalan@.nasa.gov, 301-614-6183
- Vanessa George –Vanessa.George@lasp.colorado.edu, 303-492-5486
- Jerry Harder – Jerry.Harder@lasp.colorado.edu, 303-492-1891
- Greg Kopp – Greg.Kopp@lasp.colorado.edu, 303-735-0934
- Jae Lee – Jae.N.Lee@nasa.gov, 301-614-6189
- Peter Pilewskie – Peter.Pilewskie@lasp.colorado.edu, 303-735-5589
- Erik Richard – Erik.Richard@lasp.colorado.edu, 303-735-6629
- Gary Rottman – Gary.Rottman@lasp.colorado.edu
- Marty Snow – Marty.Snow@lasp.colorado.edu, 303-735-2143
- Tom Woods – Tom.Woods@lasp.colorado.edu, 303-492-4224