The North Atlantic heat budget: an Argo based study
The Argo dataset is used to obtain estimates of the heat storage and heat divergence with the aim of the assessing the usefulness of the Argo array for investigating the North Atlantic heat budget. The accuracy of the Argo-based mixed layer heat storage varies significantly throughout the North Atla...
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Format: | Thesis |
Language: | English |
Published: |
2007
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Subjects: | |
Online Access: | https://eprints.soton.ac.uk/63138/ https://eprints.soton.ac.uk/63138/1/Hadfield_2007_PhD.pdf |
Summary: | The Argo dataset is used to obtain estimates of the heat storage and heat divergence with the aim of the assessing the usefulness of the Argo array for investigating the North Atlantic heat budget. The accuracy of the Argo-based mixed layer heat storage varies significantly throughout the North Atlantic. Errors are smallest, around 10-20 Wm-2 on monthly timescales for 10° x 10° boxes, reducing to 5-10 Wm-2 on seasonal scales in the subtropics and eastern basin. Heat storage errors over a fixed 300 m layer are higher, but typically remain below 20 Wm-2 on seasonal timescales away from the western boundary. The heat budget is closed (using net heat fluxes from the NCEP climatology and NOC reanalysis) within the estimated error throughout the subtropical and eastern North Atlantic, indicating the value of the Argo dataset in studies of this nature. However, within the western boundary the heat budget residual typically exceeds 50 Wm-2, with the heat storage overestimated or the heating from the net heat flux and/or advective and diffusive divergence underestimated. Assuming that heat storage error estimates are accurate and considering results in the literature regarding the bias in net heat flux products, it is likely that heating from divergence is underestimated. The heating contribution from this term may be large on scales that cannot be resolved using Argo. In the eastern and subtropical North Atlantic, the errors in the Argo-based heat budget terms are smaller than the uncertainty in the net heat flux products and can thus be used to provide insight into which atmospheric dataset (the NCEP reanalysis or the NOC climatology) may be more accurate. The NOC net heat flux is more accurate than that from NCEP throughout the year in the subtropics and during the first half of the year in the eastern mid-latitudes. The errors in the mixed layer heat storage are smaller than the interannual variability in this term. Thus Argo can be used to investigate variability on this scale. While the current Argo dataset is on ... |
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