Report of the

CCSM OCEAN MODEL WORKING GROUP MEETING

9 July 2004

Santa Fe, New Mexico

 

 

The stated goals of the meeting were to finalize the Ocean Model Working Group (OMWG) computing requests contained in the Climate Simulation Laboratory (CSL) proposal, to ensure that all OMWG Journal of Climate special issue papers are on track for submission by the November deadline, and to begin planning the post IPCC future. Thanks to the participants, all of these goals were met.

 

In addition, the science content of the meeting was highlighted by two presentations on recent results. Matthew Hecht (Los Alamos National Laboratory, LANL) showed the mesoscale eddy field in a 1/10 degree North Atlantic Parallel Ocean Program (POP) model interacted with high frequency (6-12 hourly) wind forcing. Most notable is the increased energy transfer compared to daily forcing. Stephen Yeager (NCAR) demonstrated how spice anomalies are generated on subducted isopycnal during late winter in the CCSM ocean model. This occurs in the very special regions of the subtropical ocean gyres where there is a strong unstable vertical salinity gradient in the upper 200-300m, and although never directly observed, agrees with the limited indirect observational evidence.

 

The OMWG computing requests and scientific justification were finalized for inclusion into the CCSM development and production proposals for allocations from the CSL. Proposed ocean model development topics included an eddy-resolving ocean; transition to POP 2.0; an isopycnal ocean; and physics upgrades such as advection, overflows, coastal coupling, stagnant sea ice, and North Atlantic sea surface temperature (SST). Proposed OMWG production integrations involve experiments on resolved ocean eddies, coupled variability, forced variability, abrupt climate change, an isopycnal ocean, and Greenland melt scenarios. Subsequently, the request was nearly completely granted, though a supplemental proposal for combined abrupt climate change studies had to be submitted and accepted.

 

There were brief discussions of all the papers being prepared for the Journal of Climate special issue. The OMWG has the primary responsibility for five papers: Attribution and Impacts of Upper Ocean Biases in CCSM3; Diurnal Ocean-Atmosphere Coupling; Ocean Chlorofluorocarbon and Heat Uptake During the 20th Century in CCSM3; and The Low Resolution CCSM3. The OMWG is also contributing to numerous other papers, including Overview of CCSM3, The Hydrological Cycle: Mean State, Impacts of Horizontal Resolution, Tropical Variability of the Coupled Ocean-Atmosphere System, Extra-tropical Coupled Ocean-Atmosphere Variability, and The Influence of Sea-Ice on Ocean Heat Uptake in Response to Increasing CO2. It is anticipated that all OMWG contributions will be submitted in time for publication in the special issue.

 

A major factor in the future of the OMWG will be collaborations between NCAR scientists and the external communities, both university and government. This was most evident in a report from the Ocean Modeling meeting held at GFDL in June 2004, and the concurrent meeting of the Working Group on Ocean Model Development. Specifically, A. Rosati (GFDL) presented results of a comparison of the CCSM and GFDL ocean model performances in the equatorial Pacific, and S. Griffies (GFDL) briefed the meeting on the Coordinated Ocean Research Experiments (CORE), which are being planned by multiple ocean modeling groups around the world. It is also evident from the involvement of the OMWG in the two CLIVAR Climate Process Teams (CPTs) on Eddy-Mixed Layer Interaction and on Gravity Current Entrainment. The goal of these CPTs is the relatively rapid implementation of recent observational and process modeling results and theoretical ideas into climate scale models.

 

Other model developments discussed include the transition to POP 2.0 (early 2005), high-resolution studies on the Earth Simulator, a rapid equilibrium (upper ocean) model (funded through LANL), and the suite of Modular Ocean Model (MOM) developments presented by S. Griffies. Very relevant aspects of the latter are the advection and time stepping.

 

The university community will lead a major effort into aspects of abrupt climate change, as described in its CSL proposal. It relates to paleoclemate activities and to the CORE Greenland melt experiments.

 

PARTICIPANTS

David Adamec

Bob Malone

David Archer

Norikazu Nakashiki

Rainer Bleck

Nancy Norton

Frank Bryan

Terry Paluszkiewicz

Antonietta Capotondi

Synte Peacock

James Carton

Todd Ringler

John Davis

Anthony Rosati

Sumner Dean

Ed Sarachik

Peter Gent

Bert Semtner

Steve Griffies

Alex Sen Gupta

Bill Holland

Rick Smith

Marika Holland

James Taft

Detelina Ivanova

Prasad Thoppil

Robert Jacob

Daisuki Tsumune

Steve Jayne

Scott Weese

Phil Jones

Steve Yeager

Bill Large