Columbia University, New York

March 19-21, 2007


The workshop will focus on mechanisms of climate change in the African Sahel. It will be very informal, with plenty of discussion organized around a set of talks assessing current knowledge and problems. The goal is to collate information coming from observations, different modeling groups, and theoretical works that could ultimately be used to distinguish between more and less trustworthy model predictions of African climate change.


The talks will focus on the observational record of African rainfall at all scales (from the fast organizations of mesoscale convective systems, to the SSTdriven interannual variability, to paleo changes in response to external forcings), physical mechanisms that are thought to be important for the region, but not yet simulated in climate models (e.g. vegetation and dust processes) and the simulations of African rainfall in current climate model (the simulation of the 20th century by atmospheric and coupled general circulation models, as well as the models' projections for the 21st century).


Organizing committee

Michela Biasutti (LDEO), Isaac Held (GFDL), Alessandra Giannini (IRI), Adam Sobel (CU), and John Chiang (UC, Berkeley).


Faculty Room, Low Library (map of Low). Columbia University, Main Campus (map of campus)


Date and Time

Monday, March 19 , 8:45am-5pm

Tuesday, March 20,  9am-5pm, off-site dinner at 6pm (at Pisticci restaurant)

Wednesday, March 21, 9am-12pm


The workshop is open to the Lamont, EI, and GISS communities. Registration not required for attending the workshop.

If you plan to attend the dinner, please confirm with

Downloadable flyer


If you are not a US citizen or permanent resident:
We will need a copy of your passport (& visa, if available) to be able to reimburse your expenses.

General Info

All talks will be 20-minute long. There will be time for questions and discussion throughout the day, as the talks progress, and in specific allotted times. Participants are encouraged to bring slides on a memory stick, if they have some results that might be useful for discussion.

Download the PDF of the agenda and list of participants (current as of 03/13/2007).


Monday, March 19, morning

Introductory Remarks and Welcome

Jeff Sachs: Welcoming address: The importance of long-term climate prediction for Sub-Saharan Africa

Peter DeMenocal: Paleo Observations of the African Monsoon

Sharon Nicholson: Observations and Mechanisms of Interannual variability in West Africa.

        Alessandra Giannini: Sahel rainfall variability in AMIP-like integrations.



Randy Koster: Land-atmosphere feedback in the Sahel.

Ning Zeng: Vegetation dynamics and effect on monsoon  +  extra  slides

Natalie Mahowald: Dust dynamics and effect on monsoon

Chris Taylor: Interactions between convection and soil moisture.


Tuesday, March 20, morning
Chris Thorncroft: Observed characteristics of the mean Sahel rainy season


Chidong Zhang: The dynamics of monsoon: lessons from the annual cycle.

John Chiang: Origins of North Atlantic SST conditions linked to Sahel rainfall

Adam Sobel: Equilibrium response to tropospheric warming over land. 
+ Jian Lu's  ppt (animation only on PCs)



David Neelin: The Zoo of Mechanisms for Tropical Rainfall Variability and Change.

Isaac Held: Changes in the hydrological cycle and tropical precipitation under global warming

Michela Biasutti: Sahel Climate Change in the IPCC AR4 models

Kerry Cook: Past and future changes in Sahel rainfall: possible mechanisms.

+ Samson Hagos' ppt (or pdf)




Wednesday, March 21, morning

       <>Open Discussion: Lessons learned  & Recommendation for future research. David Battisti moderates (ppt)

Concluding Remarks and Thanks.


Useful Information and Links

Karen Bocsusis, at the travel office at Lamont

New York City subway directions:

The Newton Hotel

Map of UWS/Morningside

Directions to/from airports: EWR, JFK, LaGuardia (unofficial site with directions to all airports)

The main entrance to Columbia University is at 116th Street and Broadway Avenue, right next to the 1 subway stop.

Travel and Expense Reimbursement Forms. These will also be handed out at the meeting:

For everyone:

Reimbursement Instructions, Sample Reimbursement Form, Reimbursement Form (please include your SSN when filling this out)

For people who aren't US citizens or permanent residents:

Form W8BEN, Statement for Alien Non-Employee Payment