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GACP Meetings

PACE Project Workshop

> Download Meeting Report (280 kB PDF)

During the second GACP meeting at GISS on Sep-Oct 1999, J. L. Brenguier, an invited speaker, presented the results from the Cloudy Column project within ACE-2 and outlined the collaboration that was planned, between experimentalists and modelers, to investigate the aerosol indirect effect.

This joint collaboration lead to the formation of the PACE project (Parameterization of the Aerosol Indirect Climatic Effect) that began on March 1 2000. This project is funded by the European Commission and was initiated by Jean-Louis Brenguier. Since our work in the GACP project is related to the objectives within PACE, we (Tony Del Genio and Surabi Menon) are involved in this project along with the following partners:

J. L. Brenguier, Météo-France, France

L. Schüller, Freie University of Berlin, Germany

H. Pawlowska, University of Warsaw, Poland

D. Roberts, The UK Met. Office, UK

J. Feichter, Max Planck Institute for Meteorology, Germany

J. Snider, University of Wyoming, USA

U. Lohmann, Dalhousie University, Canada

S. Ghan, Pacific Northwest National Laboratory, USA

To simulate the aerosol indirect effect (AIE), a Single Column Model (SCM) will be used by the modelers using the data supplied by the experimentalists. In addition, the model outputs will be inter-compared in order to distinguish numerical couplings from physical feedback processes. Under the proposed activity, the sensitivity of the AIE to aerosol activation, cloud microphysics/radiation interaction, drizzle formation and cloud dynamics will be investigated. The representation of these physical processes in the climate model will be tested by different parameterizations in order to choose those variables that need to be predicted either diagnostically or prognostically. Results from this project will be used to reduce the uncertainty in the aerosol indirect effect and improve model climate prediction capabilities.

To discuss the details and procedures to be adopted for the PACE project, five workshops are to be held within a span of two years. The first one will be held at GISS from May 1st to 5th.

The agenda of the meeting is as follows:

May 1 and May 2: Informal discussions

Wednesday, May 3: Aerosol/cloud interaction

Morning: Presentation by modelers on their parameterization schemes

09:00: 30 minutes each

MPI- Johann Feichter and Ulrike Lohmann

Hadley Centre - Dave Roberts

GISS - Surabi Menon

PNLL - Steve Ghan

11:30 : Discussion

12:30-14:00: Lunch Break

Afternoon:

14:00: Results of the activation closure experiment in ACE-2.

Jeff Snider and Sarah Guibert

15:00: Open discussion on

Initialization aerosol data set for SCM

Selection of reference cases

Methodology of the exercise for aerosol/cloud interaction validation

17:00: Reception

Thursday, May 4: Cloud/Radiation interaction

Morning: Presentation by modelers on their parameterization schemes

09:00 : 30 minutes each

MPI- Ulrike Lohmann and Johann Feichter

Hadley Centre - Dave Roberts

GISS - Tony Del Genio

PNLL - Steve Ghan

11:30 : Discussion

12:30-14:00: Lunch Break

Afternoon:

14:00: Results of the cloud and radiation closure experiment in ACE-2. New

insight on cloud heterogeneity effects:

14:00 Hanna Pawlowska: cloud properties

15:00 Lothar Schuller: radiative properties

16:00: Open discussion on

Initialization thermodynamics data set for SCM

Selection of reference cases

Methodology of the exercise for cloud/radiation interaction validation

Friday, May 5: Open discussion on sub-grid cloud parameterization

Morning:

09:00: Discussion on sub-grid parameterization

10:00: LES cloud simulations for ACE-2: F. Troude

11:00: Discussion

12:30-14:00: Lunch Break

Afternoon:

14:00: General discussion, preparation of the report and possibly a paper

(Bull. Amer. Meteorol. Soc.). Actions for next 6 months and next meeting.


For more information, contact:

Jean-Louis Brenguier ( jean-louis.brenguier@meteo.fr)
or
Surabi Menon
NASA GISS/Columbia Univ
2880 Broadway
New York, NY 10025
smenon@giss.nasa.gov
Tel: 212 678 5592
Fax: 212 678 5552