Report on CCSM Paleoclimate Working Group Meeting

Seventh Annual CCSM Workshop, The Village at Breckenridge

Co-Chairs: Lisa Sloan (assisted by Esther Brady)

25 June 2002

Meeting presentations and discussions are listed in chronological order:

1. Lisa Sloan presented a summary of the status of a "paleo" CCSM2 model. She noted that currently a "paleo" model only exists for present-day conditions, and that this is not sufficient. The PcWG needs a model that can cope with conditions completely different from present day (e.g., land-sea distribution, topography and bathymetry, vegetation types, ocean heat fluxes, soil characteristics, etc.). Such a model currently does not exist.
   
   
2. Presenters of posters gave 5-minute summaries of their posters, as introductions to the evening poster sessions. Presentations were made by Matt Huber (DCESS), Ilana Warner (Brazil), Masa Yoshimoto (Bern), and Esther Brady (NCAR).
   
   
3. Cindy Shellito (UCSC) presented ongoing results of the development of a "paleo" CAM with a slab ocean model (SOM) for past land-sea distributions. She highlighted issues such as the importance of choosing a reasonable "Q factor" value and the need for tuning heat flow under sea ice for past land-sea distributions. She estimated that the PcWG should have a working version of CAM/SOM for non-present land-sea distributions by August 2002.
   
   
4. Rick Smith (LANL) provided introduction and considerations for creating global land/ocean grids for paleogeographies different from present. He gave examples of the types of dipole and tripole grids that would be required for vastly different land-sea distributions that have occurred throughout Earth history. It was agreed that Smith would work with Brady and Sloan to make these calculations and grids more readily available to the PcWG community.
   
   
5. Sam Levis (NCAR) provided an introduction to and summary of attributes of the new land model (CLM2), highlighting issues of key concern to the PcWG. Of critical importance for the working group are the river routing scheme and the dynamic vegetation. The PcWG participants agreed that they will need to investigate these issues in more detail in the future, in order to take advantage of these improvements for paleoclimate research.
   
   
6. Lawrence Buja (NCAR) provided an overview of how the Software Engineering Working Group (SEWG) can assist members of the PcWG. The PcWG anticipates working more closely with members of the SEWG in the future.
   
   
7. Christine Shields (NCAR) introduced the PcWG to CCSM web page visualization capabilities. The PcWG agreed that they would like to have NCAR consider supporting full time a person to create and maintain such diagnostic packages for all model components (including in their paleoclimate versions).
   
   
8. Mark Eakin (NOAA) demonstrated the data archiving and interactive visualization capabilities that are available via NOAA's website. Eakin urged the PcWG to more carefully consider archiving their model results at NOAA in the future.
   
   
9. Esther Brady (NCAR) presented results of a CCSM2 (with T31 atmosphere) experiment (present day conditions and paleo resolution) that would form the basis for the PcWG control run. Results were discussed at length and the PcWG members endorsed the need for a long (multi-century) control run at T31 resolution, for the community to access as needed.
   
   
10. A discussion (led by Sloan and Brady) led to the identification of the following goals by members of the PcWG:

Short term (0-12 months) goals:

Create a fully-functional, true paleoCCSM. This will require fulfilling the following needs:

• establish methods and generate grids for various past land/sea distributions. The initial focus will be on generating data sets for 60 and 80 million years ago. (Brady, Otto-Bliesner, Sloan, and Smith)
  
  
• establish methods and generate (a) topographic and bathymetric data sets and (b) river routing data sets (Sloan & UCSC, Brady, Smith, Otto-Bliesner)
  
  
• generate a longer present day control run at T31, and generate extra developmental runs to examine the model sensitivity to bottom topography, and runoff distributions over the oceans.
  
  
• convene a PcWG meeting in late winter or early spring to assess progress made.

We note that the PcWG will need substantial assistance from the SEWG.

Longer term (6-18 month) goals:

Continue refining a fully functional true paleoCCSM2, and move forward with our main research themes of (1) climate of the 17th,18th, and 19th centuries, (2) climate of the past 21,000 years, and (3) climates of extreme warmth of the past 100 million years.

To do this we anticipate creating CLM2 data sets, investigating impacts of model resolution, and investigating spin up methods for dynamic vegetation in paleoclimate model versions.

Participant List

Gordon Bonan
Esther Brady
C. Mark Eakin
Johannes Feddema
Charles Hakkarinen
David Hosansky
Fortunat Joos
Zavareh Kothavala
Brett Longworth
Michael MacCracken
Keith Oleson
Elisabetta Pierazzo
Christoph Raible
Nan Rosenbloom
Olga Sergienko
Jacob Sewall
Lucinda Shellito
Christine Shields
Lisa Sloan
Leah May Ver
Ilana Wainer
Charles Zender
Masakazu Yoshimori