scholarly journals Predicting Coupled Ocean-Atmosphere Modes with a Climate Modeling Hierarchy -- Final Report

2006 ◽  
Author(s):  
UCLA Michael Ghil ◽  
UC Irvine Padhraic Smyth
Keyword(s):  
Climate Modeling ◽  
Final Report ◽  
Ocean Atmosphere

scholarly journals Response of ENSO and the Mean State of the Tropical Pacific to Extratropical Cooling and Warming: A Study Using the IAP Coupled Model

2009 ◽  
Vol 22 (22) ◽  
pp. 5902-5917 ◽  
Author(s):  
Y. Yu ◽  
D-Z. Sun
Keyword(s):  
Climate Change ◽  
Climate Modeling ◽  
Coupled Model ◽  
Tropical Pacific ◽  
Equatorial Region ◽  
Upper Ocean ◽  
Central Pacific ◽  
Intergovernmental Panel ◽  
Ocean Atmosphere ◽  
The Tropical Pacific

Abstract The coupled model of the Institute of Atmospheric Physics (IAP) is used to investigate the effects of extratropical cooling and warming on the tropical Pacific climate. The IAP coupled model is a fully coupled GCM without any flux correction. The model has been used in many aspects of climate modeling, including the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) climate change and paleoclimate simulations. In this study, the IAP coupled model is subjected to cooling or heating over the extratropical Pacific. As in an earlier study, the cooling and heating is imposed over the extratropical region poleward of 10°N–10°S. Consistent with earlier findings, an elevated (reduced) level of ENSO activity in response to an increase (decrease) in the cooling over the extratropical region is found. The changes in the time-mean structure of the equatorial upper ocean are also found to be very different between the case in which ocean–atmosphere is coupled over the equatorial region and the case in which the ocean–atmosphere over the equatorial region is decoupled. For example, in the uncoupled run, the thermocline water across the entire equatorial Pacific is cooled in response to an increase in the extratropical cooling. In the corresponding coupled run, the changes in the equatorial upper-ocean temperature in the extratropical cooling resemble a La Niña situation—a deeper thermocline in the western and central Pacific accompanied by a shallower thermocline in the eastern Pacific. Conversely, with coupling, the response of the equatorial upper ocean to extratropical cooling resembles an El Niño situation. These results ascertain the role of extratropical ocean in determining the amplitude of ENSO. The results also underscore the importance of ocean–atmosphere coupling in the interaction between the tropical Pacific and the extratropical Pacific.

scholarly journals Practice and philosophy of climate model tuning across six U.S. modeling centers

2017 ◽  
Author(s):  
Gavin A. Schmidt ◽  
David Bader ◽  
Leo J. Donner ◽  
Gregory S. Elsaesser ◽  
Jean-Christophe Golaz ◽  
...  
Keyword(s):  
Model Calibration ◽  
Climate Models ◽  
Climate Model ◽  
Climate Modeling ◽  
Abstract Model ◽  
Ocean Atmosphere ◽  
Climate Model Output ◽  
Model Tuning ◽  
Key Aspects ◽  
Scientific Purpose

Abstract. Model calibration (or "tuning") is a necessary part of developing and testing coupled ocean-atmosphere climate models regardless of their main scientific purpose. There is an increasing recognition that this process needs to become more transparent for both users of climate model output and other developers. Knowing how and why climate models are tuned and which targets are used is essential to avoiding possible misattributions of skillful predictions to data accommodation and vice versa. This paper describes the approach and practice of model tuning for the six major U.S. climate modeling centers. While details differ among groups in terms of scientific missions, tuning targets and tunable parameters, there is a core commonality of approaches. However, practices differ significantly on some key aspects, in particular, in the use of initialized forecast analyses as a tool, the explicit use of the historical transient record, and the use of the present day radiative imbalance vs. the implied balance in the pre-industrial as a target.

scholarly journals Practice and philosophy of climate model tuning across six US modeling centers

2017 ◽  
Vol 10 (9) ◽  
pp. 3207-3223 ◽  
Author(s):  
Gavin A. Schmidt ◽  
David Bader ◽  
Leo J. Donner ◽  
Gregory S. Elsaesser ◽  
Jean-Christophe Golaz ◽  
...  
Keyword(s):  
Model Calibration ◽  
Climate Models ◽  
Climate Model ◽  
Climate Modeling ◽  
Abstract Model ◽  
Ocean Atmosphere ◽  
Climate Model Output ◽  
Model Tuning ◽  
Key Aspects ◽  
Scientific Purpose

Abstract. Model calibration (or tuning) is a necessary part of developing and testing coupled ocean–atmosphere climate models regardless of their main scientific purpose. There is an increasing recognition that this process needs to become more transparent for both users of climate model output and other developers. Knowing how and why climate models are tuned and which targets are used is essential to avoiding possible misattributions of skillful predictions to data accommodation and vice versa. This paper describes the approach and practice of model tuning for the six major US climate modeling centers. While details differ among groups in terms of scientific missions, tuning targets, and tunable parameters, there is a core commonality of approaches. However, practices differ significantly on some key aspects, in particular, in the use of initialized forecast analyses as a tool, the explicit use of the historical transient record, and the use of the present-day radiative imbalance vs. the implied balance in the preindustrial era as a target.

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