A New Surface Mixed-layer and Sea-ice Parameterization for Use with an Oceanic General Circulation Model PDF Download

Author: Young June Han
Publisher:
ISBN:
Category : Ocean circulation
Languages : en
Pages : 23

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Author: Robert C. Heald
Publisher:
ISBN:
Category : Climatology
Languages : en
Pages : 48

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Book Description
The behavior of different parameterizations of mixed layer physics when used in an oceanic general circulation model (OGCM) having coarse resolution of the upper ocean is examined. The method of parameterization is expected to have an important effect on the resulting sea surface temperature, and hence affect the model's overall fidelity from the viewpoint of air-sea interaction. Tests of three possible parameterizations differ in the manner in which the mixed layer depth is determined: predetermination, diagnostic determination, or prognostic determination. The sea surface temperature is taken to be equivalent to the top OGCM layer temperature in the first two methods, while it is found prognostically in the third method. Results show that for typical forcing cases such as strong insolation, weak surface cooling or weak winds, mixing is insufficient to cause heat transfer between the top two OGCM layers, which occupy the uppermost 500 m of the model. The predetermined and diagnostically determined mixed layer depth parameterizations reduce to a diffusive mixing parameterization, while the prognostic approach satisfactorily models mixed layer depths for all forcing cases. The prognostic method also agrees most closely with the results of a mixed layer model and with observations.

Author: Eric P. Chassignet
Publisher: Springer Science & Business Media
ISBN: 9401150966
Category : Science
Languages : en
Pages : 459

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Book Description
The realism of large scale numerical ocean models has improved dra matically in recent years, in part because modern computers permit a more faithful representation of the differential equations by their algebraic analogs. Equally significant, if not more so, has been the improved under standing of physical processes on space and time scales smaller than those that can be represented in such models. Today, some of the most challeng ing issues remaining in ocean modeling are associated with parameterizing the effects of these high-frequency, small-space scale processes. Accurate parameterizations are especially needed in long term integrations of coarse resolution ocean models that are designed to understand the ocean vari ability within the climate system on seasonal to decadal time scales. Traditionally, parameterizations of subgrid-scale, high-frequency mo tions in ocean modeling have been based on simple formulations, such as the Reynolds decomposition with constant diffusivity values. Until recently, modelers were concerned with first order issues such as a correct represen tation of the basic features of the ocean circulation. As the numerical simu lations become better and less dependent on the discretization choices, the focus is turning to the physics of the needed parameterizations and their numerical implementation. At the present time, the success of any large scale numerical simulation is directly dependent upon the choices that are made for the parameterization of various subgrid processes.

Author: M.E. Schlesinger
Publisher: Springer Science & Business Media
ISBN: 9400920938
Category : Science
Languages : en
Pages : 379

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Book Description
Preface This book is the culmination of a workshop jointly organized by NATO and CEC on Climate-Ocean Interaction which was held at Lady Margaret Hall, Oxford University during 26-30 September 1988. The objective of the ARW was to assess the current status of research on climate-ocean interaction, with a major focus on the development of coupled atmosphere-ocean-ice models and their application in the study of past, present and possible future climates. This book contains 16 chapters divided into four parts: Introduction; Observations of the Climate of the Ocean; Modelling the Atmospheric, Oceanic and Sea Ice Components of the Climatic System; and Simulating the Variability of Climate on Short, Medium and Long Time Scales. A fifth part contains the reports of the five Working Groups on: Climate Observations, Modelling, ENSO Modelling and Prediction, Climate-Ocean Interaction on TIme Scales of Decades to Centuries, and Impact of Paleoclimatic Proxy Data on Climate Modelling. Preface ix Acknowledgements I thank Howard Cattle and Neil Wells for their guidance and assistance as members of the Workshop Organizing Committee. I particularly thank Michael Davey for all his efforts as Local Organizer to make the ARW a success. I also thank the staff of Lady Margaret Hall, Oxford University, for their help with the arrangements for the ARW.

Author: David Pollard
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 49

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Author: Tong Lee
Publisher: Frontiers Media SA
ISBN: 2889631206
Category : Science
Languages : en
Pages : 867

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Book Description
This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Author: Martin Vancoppenolle
Publisher: Presses univ. de Louvain
ISBN: 2874631132
Category : Science
Languages : en
Pages : 229

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Book Description
Ice formed from seawater, called sea ice, is both an important actor in and a sensitive indicator of climate change. Covering 7% of the World Ocean, sea ice damps the atmosphere-ocean exchanges of heat, radiation and momentum in polar regions. It also affects the oceanic circulation at a global scale. Recent satellite and submarine observations systems indicate a sharp decrease in the extent and volume of Arctic sea ice over the last 30 years. In addition, climate models project drastic sea ice reductions for the next century, in both hemispheres, with potentially large consequences on climate and ecosystems. Contrary to what is commonly believed, sea ice retains about 25% of the oceanic salt when it forms. As salt cannot lock in the ice crystalline lattice, it accumulates in liquid inclusions of salty water (brine). Under a temperature change, the inclusions freeze or melt and release or absorb huge amounts of latent heat. This affects heat transfer through and storage in sea ice, which may affect the mass balance of sea ice at a global scale. This is the central hypothesis of this work. In order to address this problem, the author develops two sea ice models and assesses their ability to simulate the recent evolution of the sea ice mass balance. Then, the physics of brine uptake and drainage are included in the models and sea ice desalination is investigated. Finally, the impact of sea ice salinity variations on the global sea ice mass balance is studied. The roles of sea ice thermal properties, of ice-ocean salt / fresh water fluxes and of oceanic feedbacks are evaluated. The new salinity module improves the simulation of ice and ocean characteristics compared to observations. Including salinity variations increases ice growth, reduces vertical mixing in the ocean and the ocean-to-ice heat flux. In conclusion, salinity variations should be included in future sea ice models used for climate projections.

Author: Peter R. Gent
Publisher: Elsevier Inc. Chapters
ISBN: 0128058722
Category : Science
Languages : en
Pages : 43

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Book Description
Coupled climate models consist of atmosphere, ocean, land, and sea ice components. Most climate models now do not need to use flux adjustments to maintain the present-day climate in a control run, when the forcings have a repeating annual cycle or are constant in time. A control run must simulate well-known important large-scale phenomena, such as the El Nino/Southern Oscillation and the North Atlantic overturning circulation. Climate models are used to simulate the climate of the twentieth century, and to make projections of the future climate. The uses and limitations of climate models are then described, and several cutting edge issues are discussed.

Author: Edward Joseph Metzger
Publisher:
ISBN:
Category : Ocean-atmosphere interaction
Languages : en
Pages : 230

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Author: David L.T. Anderson
Publisher: Springer Science & Business Media
ISBN: 9783540614593
Category : Nature
Languages : en
Pages : 508

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Book Description
Proceedings of the NATO Advanced Study Institute "Decadal Climate Variability: Dynamics and Predictability", held at Les Houches, France, February 13-24, 199