World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Oceanic Dominance of Interannual Subtropical North Atlantic Heat Content Variability : Volume 10, Issue 1 (10/01/2013)

By Sonnewald, M.

Click here to view

Book Id: WPLBN0004020745
Format Type: PDF Article :
File Size: Pages 27
Reproduction Date: 2015

Title: Oceanic Dominance of Interannual Subtropical North Atlantic Heat Content Variability : Volume 10, Issue 1 (10/01/2013)  
Author: Sonnewald, M.
Volume: Vol. 10, Issue 1
Language: English
Subject: Science, Ocean, Science
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Historic
Publication Date:
2013
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Description
Description: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK. Ocean heat content varies on a range of timescales. Traditionally the atmosphere is seen to dominate the oceanic heat content variability. However, this variability can be driven either by oceanic or atmospheric heat fluxes. To diagnose the relative contributions and respective timescales, this study uses a box model forced with output from an ocean general circulation model (OGCM) to investigate the heat content variability of the upper 800 m of the subtropical North Atlantic from 26° N to 36° N. The ocean and air-sea heat flux data needed to force the box model is taken from a 19 yr (1988 to 2006) simulation performed with the 1/12° version of the OCCAM OGCM. The box model heat content is compared to the corresponding heat content in OCCAM for verification. The main goal of the study is to identify to what extent the seasonal to interannual ocean heat content variability is of atmospheric or oceanic origin. To this end, the box model is subjected to a range of scenarios forced either with the full (detrended) ocean and air-sea fluxes, or their deseasoned counterparts. Results show that in all cases, the seasonal variability is dominated by the seasonal component of the air-sea fluxes, which produce a seasonal range in mean temperature of the upper 800 m of ~ 0.42 °C. However, on longer timescales oceanic heat transport dominates, with changes of up to ~ 0.30 °C over 4 yr.

The technique is subsequently applied to observational data. For the ocean heat fluxes, we use data from the RAPID program at 26° N from April 2004 to January 2011. At 36° N heat transport is inferred using a linear regression model based on the oceanic low-frequency transport in OCCAM. The air-sea flux from OCCAM is used for the period 2004 to 2006 when the RAPID timeseries and the OCCAM simulation overlap, and a climatology is used for the air-sea flux from 2006 onwards. The results confirm that on longer (> 2 yr) timescales the ocean dominates the ocean heat content variability, which is further verified using data from the ARGO project. This work illustrates that oceanic divergence significantly impacts the ocean heat content variability on timescales relevant for applications such as seasonal hurricane forecasts.


Summary
Oceanic dominance of interannual subtropical North Atlantic heat content variability

Excerpt
Atkinson, C. P., Bryden, H. L., Hirschi, J. J-M., and Kanzow, T.: On the seasonal cycles and variability of Florida Straits, Ekman and Sverdrup transports at 26{\degree} N in the Atlantic Ocean, Ocean Sci., 6, 837–859, doi:10.5194/os-6-837-2010, 2010.; Baringer, M. O. and Molinari, R.: Atlantic Ocean baroclinic heat fl}ux at 24 to 26{\degree N, Geophys. Res. Lett., 26, 353–356, 1999.; Bryden, H. L. and Imawaki. S.: Ocean heat transport, in: Ocean Circulation and Climate, edited by: Siedler, G., Church, J., and Gould, J., London, Academic Press, 455–474, 2001.; Coward, A. C. and de Cuvas, B. A.: The OCCAM 66 level model: physics, initial conditions and external forcing, SOC internal report, No. 99, 2005.; Cunningham, S. A., Kanzow, T., Rayner, D., Baringer, M. O., Johns, W. E., Marotzke, J., Longworth, H. R., Grant, E. M., Hirschi, J. J.-M., Beal, L. M., Meinen, C. S. and Bryden, H. L.: Temporal variability of the Atlantic meridional overturning circulation at 26.5{\degree} N, Science, 317, 935–938, doi:10.1126/science.1141304, 2007.; Domingues, C. M., Church, J. A., White, N. J., Gleckler, P. J., Wijffels, S. E., Barker, P. M., and Dunn, J. R.: Improved estimates of upper-ocean warming and multi-decadal sea-level rise, Nature, 453, 1090–1093, 2008.; Dong, B. and Sutton, R. T.: Mechanism of interdecadal thermohaline circulation variability in a coupled ocean–atmosphere GCM, J. Climate, 18, 1117–1135, 2005.; Fasullo, J. T. and Trenberth, K. E.: The annual cycle of the energy budget, Part II: Meridional structures and poleward transports, J. Climate, 21, 2313–2325, 2008.; Feulner, G. and Rahmstorf, S.: On the effect of a new grand minimum of solar activity on the future climate on Earth, Geophys. Res. Lett., 37, L05707, doi:10.1029/2010GL042710, 2010.; Grossmann, I. and Morgan, M. G.: Tropical cyclones, climate change, and scientific uncertainty: what do we know, what does it mean, and what should be done? Climatic Change, 108, 543–579, 2011.; Grist, J. P., Marsh, R., and S. A. Josey, S. A.: On the relationship between the North Atlantic meridional overturning circulation and the surface-forced overturning stream function, J. Climate, 22, 4989–5002, doi:10.1175/2009JCLI2574.1, 2009.; Grist, J. P., Josey, S. A., Marsh, R., Good, S. A., Coward, A. C., de Cuevas, B. A., Alderson, S. G., New, A. L., and Madec, G.: The roles of surface heat flux and ocean heat transport convergence in determining Atlantic Ocean temperature variability, Ocean Dynam., 60, 771–790, doi:10.1007/s10236-010-0292-4, 2010.; Hirschi, J. J.-M., Baehr, J., Marotzke, J., Stark, J., Cunningham, S., and Beismann, J.-O.: A monitoring design for the Atlantic meridional overturning circulation, Geophys. Res. Lett., 30, 1413, doi:

 

Click To View

Additional Books


  • Roles of Initial Ocean Surface and Subsu... (by )
  • Technical Note: a Low Cost Unmanned Aeri... (by )
  • How Does Ocean Ventilation Change Under ... (by )
  • Descent and Mixing of the Overflow Plume... (by )
  • Assessment of the Impact of Ts Assimilat... (by )
  • The Impacts of Physical Processes on Oxy... (by )
  • North Atlantic 20Th Century Multidecadal... (by )
  • Impact of Variable Sea-water Conductivit... (by )
  • Assimilating Globcolour Ocean Colour Dat... (by )
  • Usefulness of High Resolution Coastal Mo... (by )
  • Investigation of Saline Water Intrusions... (by )
  • The Effect of Various Vertical Discretiz... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.