Venus - Climate Focus Group

Report to VEXAG #5, May 7-8, 2008.

David Grinspoon Denver Museum of Nature & Science Venus - Earth Climate Focus Group Session convened by L. Esposito at VEXAG #4, November 2007:

Decision to form Focus Group. David Grinspoon, Chair Venus - Earth Climate Focus Group Issue: Include Mars? Titan? Outreach to Earth science community Briefing at NASA HQ, Friday May 2, 2008 David Grinspoon Ellen Stofan Jim Green, Director Planetary Sciences Division John Labrecque, Solid Earth Program Scientist Don Anderson, Earth Climate Program Scientist Madhulika Guhathakurta, Sun-Earth Connections Adriana Ocampo Brian Toon Mark Bullock Report of the COMPARATIVE PLANETARY CLIMATOLOGY Focus Group

David Grinspoon Denver Museum of Nature & Science 5/2/08 COMPARATIVE PLANETARY CLIMATOLOGY Focus Group

David Grinspoon, DMNS Sanjay Limaye, WU Ellen Stofan, Proxemy Research Eric Chassefiere, LMD Larry Esposito, LASP Kevin McGouldrick, DMNS Curt Covey, LLNL Alex Pavlov, U. Arizona Gerry Schubert, UCLA Yuk Yung, Cal Tech Mustapha Chahine, JPL Gerald Keating, GWU Gavin Schmidt, GISS Dave Crisp, JPL Fian Teng, NCAR Kevin Baines, JPL Lennart Bengtson, ISSI Janet Luhmann,UC Berkeley Jack Mustard, Brown University Stephen Mackwell, LPI Brian Toon, U. Colorado Mark Allen, JPL Mark Bullock, SwRI James Cutts, JPL Ray Pierrehumbert, U. Chicago Tibor Balint, JPL James Hansen, GISS Sushil Atreya, U. Mich James Head, Brown University Tony Colaprete, NASA/Ames James Kasting, Penn State Jean Dickey, JPL COMPARATIVE PLANETARY CLIMATOLOGY Focus Group Science Connections I Venus and Mars provide our closest (and only) planetary analogs for many important terrestrial climate processes.

Many scientific problems of common interest to both terrestrial and planetary modeling communities: •aerosol microphysics and radiative properties. •cloud morphologies and climate forcings. •mesoscale and vortex dynamics. •radiative transfer with variable trace gases. •atmospheric responses to short and long term solar forcing.

Simulating the extreme climates of these other planets can: •expose potential limitations of current climate models. •increase facility with nonlinear climate feedbacks. COMPARATIVE PLANETARY CLIMATOLOGY Focus Group Science Connections II

Understanding of Venus and Mars climate science would benefit greatly from use of the best Earth models and the expertise of the larger community of Earth scientists.

Why now? Multiple Mars missions have now produced an extensive atmospheric database.

Circulation models are more mature.

Venus Express - the first Venus climate orbiter, has now returned 2 years of data. COMPARATIVE PLANETARY CLIMATOLOGY Science Connections III - Comparative Climatology: •Venus as an extreme case of global warming.

• Obliquity cycles and climate histories of Mars and Earth.

• Clouds and radiative balance, including microphysics, cloud morphology, dynamics and cloud coverage .

• Photochemistry of Cl, O, and S .

•Responses to solar cycle.

•Responses to long-term solar evolution, constraints on solar climate forcing.

•Volcano-climate interactions. COMPARATIVE PLANETARY CLIMATOLOGY Science Connections IV - Climate Evolution:

•The role of water in the terrestrial planets.

•Noble gases as indicators of terrestrial planet origin and evolution.

•Stable isotopes of C, H, O, S and N as tracers of atmospheric sources and sinks and markers of potential ancient biospheres.

•Implications of Venusian and Martian climatic and tectonic evolution for the future of Earth.

•Nonlinear global systems theory.

Science Connections V - Atmospheric Dynamics: •Explain Venus and Mars global circulation with modeling techniques developed for terrestrial GCMs.

•Study atmospheric and exchange with solid planet on Venus and Earth, including, for example ENSO-connected variations of Earth's rotation period.

•Compare Venus dynamical phenomena to Earth stratospheric Quasi-Biennial oscillation.

•Characterize vorticity and storm morphology on Venus and Mars and compare to Earth.

•Compare the Venus and Mars middle atmospheres to Earth’s middle atmosphere.

•Characterize Venus and Earth polar vortices. COMPARATIVE PLANETARY CLIMATOLOGY Science Connections VI - Space :

•Use Venus and Mars as analogs for Earth magnetosphere and solar wind interactions during future and past magnetic field reversals.

•Model atmospheric escape on Venus, Mars and Earth, including present day escape and fractionations, and those in the early solar system (enhanced XUV and solar wind).

•Compare the solar cycle response of the upper atmospheres, exospheric escape fluxes and climates on all three planets.

•Characterize the space environments and the upper atmospheres. Recent European Interest in Comparative Climatology: ISSI Bern Expert Group Meeting 7-9 April, 2008

Balogh Andre [email protected] A meeting to discuss scientific issues of the Venus Climate and Atmosphere took place at ISSIB, Benergnt s7s-9o nApril 20L0e8n wniathrt the followinlge npanratircti.pbaenntsg:t [email protected]

Bonnet Roger Maurice [email protected] SCIENTIFIC ISSUES: Balogh Andre [email protected] BGerningtsspsoono n LenDnaavrti d David.Glreinnnsaprto.boenn@[email protected] Bonnet Roger Maurice [email protected] •Super-rotation of the GLreibnsopnonooni s DaSviedb astien [email protected]@dmns.org Lebonnois Sebastien [email protected] Limaye Sanjay [email protected] Venus Atmosphere Limaye Sanjay [email protected] Roossssi i AnAgenlog ePlioo Pio arossi@[email protected] Schmidt Hauke [email protected] •Vortex Circulation TSictohvm idt DimHiatrui ke hauke.scthitomvi@[email protected] Yamamoto Masaru [email protected] Titov Dimitri [email protected] •Quantifying the role of Yamamoto Masaru [email protected] topography •Nature and formation of clouds ISSI Bern Expert Group Recommendations: • Set up a working group from 1 July 2008 with a two year perspective having the following objectives: 1) Organize standardize comparative model simulation experiments of the Venus atmosphere. Explore sensitivities, to dynamical core, to initialization and boundary conditions. Explore time scales and internal variability. 2) Comparison with analogous terrestrial phenomena. 3) Support this work with simpler conceptual models. 4) Validate using available data from Venus Express and other sources. 5) Based on results provide advice for ongoing and future missions. COMPARATIVE PLANETARY CLIMATOLOGY Focus Group

Education and Public Outreach:

Comparative Planetary Climatology has huge potential for public excitement and education about planetary science, , and Sun-Earth connections!

Connects several aspects of current NASA science to areas of great public concern and relevance.

COMPARATIVE PLANETARY CLIMATOLOGY Focus Group

STRATEGY: •Continue to seek input from Earth, Mars, Venus and Solar science communities. (MEPAG, OPAG, etc.) •Begin planning a conference or series of workshops on Comparative Planetary Climatology. (Chapman Conference? AGU Special Session?) •Explore the possibility of an amendment to ROSES 2009, for a Research Program in Comparative Planetary Climatology.