scholarly journals The low-resolution CCSM2 revisited: new adjustments and a present-day control run

Ocean Science ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 151-181 ◽  
Author(s):  
M. Prange
Keyword(s):  
North Atlantic ◽  
Meridional Overturning Circulation ◽  
Climate System ◽  
System Model ◽  
Low Resolution ◽  
Overturning Circulation ◽  
Community Climate System Model ◽  
Climate System Model ◽  
Meridional Overturning ◽  
Community Climate

Abstract. The low-resolution (T31) version of the Community Climate System Model CCSM2.0.1 is revisited and adjusted by deepening the Greenland-Scotland ridge, changing oceanic mixing parameters, and applying a regional freshwater flux adjustment at high northern latitudes. The main purpose of these adjustments is to maintain a robust Atlantic meridional overturning circulation which collapses in the original model release. The paper describes the present-day control run of the adjusted model (referred to as "CCSM2/T31x3a") which is brought into climatic equilibrium by applying a deep-ocean acceleration technique. The accelerated integration is extended by a 100-year synchronous phase. The simulated meridional overturning circulation has a maximum of 14×106 m3 s−1 in the North Atlantic. The CCSM2/T31x3a control run is evaluated against observations and simulations with other climate models. Most shortcomings found in the CCSM2/T31x3a control run are identified as "typical problems" in global climate modelling. Finally, examples (simulation of North Atlantic hydrography, West African monsoon) are shown in which CCSM2/T31x3a has a better simulation skill than the latest low-resolution Community Climate System Model release, CCSM3/T31.

scholarly journals The low-resolution CCSM2 revisited: new adjustments and a present-day control run

2006 ◽  
Vol 3 (4) ◽  
pp. 1293-1348 ◽  
Author(s):  
M. Prange
Keyword(s):  
Meridional Overturning Circulation ◽  
Climate System ◽  
System Model ◽  
Climate Modelling ◽  
Low Resolution ◽  
Overturning Circulation ◽  
Community Climate System Model ◽  
Climate System Model ◽  
Meridional Overturning ◽  
Community Climate

Abstract. The low-resolution (T31) version of the Community Climate System Model CCSM2.0.1 is revisited and adjusted by deepening the Greenland-Scotland ridge, changing oceanic mixing parameters, and applying a regional freshwater flux adjustment at high northern latitudes. The main purpose of these adjustments is to maintain a robust Atlantic meridional overturning circulation which collapses in the original model release. The paper describes the present-day control run of the adjusted model which is brought into climatic equilibrium by applying a deep-ocean acceleration technique. The accelerated integration is extended by a 100-year synchronous phase. The simulated meridional overturning circulation has a maximum of 14×106 m3 s−1 in the North Atlantic. Most shortcomings found in the control run are identified as "typical problems" in global climate modelling. Given its good simulation skills and its relatively low resource demands, the adjusted low-resolution version of CCSM2.0.1 appears to be a reasonable alternative to the latest low-resolution Community Climate System Model release (CCSM3.0) if runtime is a critical factor.

scholarly journals A Scalable and Adaptable Solution Framework within Components of the Community Climate System Model

2009 ◽  
pp. 332-341 ◽  
Author(s):  
Katherine J. Evans ◽  
Damian W. I. Rouson ◽  
Andrew G. Salinger ◽  
Mark A. Taylor ◽  
Wilbert Weijer ◽  
...  
Keyword(s):  
Climate System ◽  
System Model ◽  
Community Climate System Model ◽  
Climate System Model ◽  
Community Climate

scholarly journals Impact of Agulhas Leakage on the Atlantic Overturning Circulation in the CCSM4

2014 ◽  
Vol 27 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Wilbert Weijer ◽  
Erik van Sebille
Keyword(s):  
North Atlantic ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Overturning Circulation ◽  
Climate System Model ◽  
The North ◽  
Salinity Variability ◽  
Meridional Overturning ◽  
The North Atlantic ◽  
The Impact

Abstract The impact of Agulhas leakage variability on the strength of the Atlantic meridional overturning circulation (AMOC) in the Community Climate System Model, version 4 (CCSM4) is investigated. In this model an advective connection exists that transports salinity anomalies from the Agulhas region into the North Atlantic on decadal (30–40 yr) time scales. However, there is no identifiable impact of Agulhas leakage on the strength of the AMOC, suggesting that the salinity variations are too weak to significantly modify the stratification in the North Atlantic. It is argued that this study is inconclusive with respect to an impact of Agulhas leakage on the AMOC. Salinity biases leave the South Atlantic and Indian Oceans too homogeneous, in particular erasing the observed salinity front in the Agulhas retroflection region. Consequently, salinity variability in the southeastern South Atlantic is found to be much weaker than observed.

scholarly journals Widely awaited community climate system model to be released soon

Eos ◽  
2002 ◽  
Vol 83 (11) ◽  
pp. 119
Author(s):  
Robert E. Dickinson ◽  
Jeffery Kiehl ◽  
Peter Gent
Keyword(s):  
Climate System ◽  
System Model ◽  
Community Climate System Model ◽  
Climate System Model ◽  
Community Climate

Sensitivity of Tropical Rainfall to Banda Sea Diffusivity in the Community Climate System Model

2008 ◽  
Vol 21 (23) ◽  
pp. 6445-6454 ◽  
Author(s):  
Markus Jochum ◽  
James Potemra
Keyword(s):  
General Circulation ◽  
Thick Layer ◽  
General Circulation Models ◽  
Climate System ◽  
System Model ◽  
Boreal Summer ◽  
Community Climate System Model ◽  
Climate System Model ◽  
Indonesian Seas ◽  
Community Climate

Abstract Several observational studies suggest that the vertical diffusivity in the Indonesian marginal seas is an order of magnitude larger than in the open ocean and what is used in most ocean general circulation models. The experiments described in this paper show that increasing the background diffusivity in the Banda Sea from the commonly used value of 0.1 cm2 s−1 to the observed value of 1 cm2 s−1 improves the watermass properties there by reproducing the observed thick layer of Banda Sea Water. The resulting reduced sea surface temperatures lead to weaker convection and a redistribution of precipitation, away from the Indonesian seas toward the equatorial Indian and Pacific Oceans. In particular, the boreal summer precipitation maximum of the Indonesian seas shifts northward from the Banda Sea toward Borneo, which reduces a longstanding bias in the simulation of the Austral–Asian Monsoon in the Community Climate System Model. Because of the positive feedback mechanisms inherent in tropical atmosphere dynamics, a reduction in Banda Sea heat loss of only 5% leads locally to a reduction in convection of 20%.

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