Published online by Cambridge University Press: 05 April 2012
Introduction to Overflows
What Are Dense Overflows?
Dense water formed in semi-enclosed seas often has to flow through narrow straits or down continental slopes before it reaches the open ocean. These regions of dense water flowing over topography are known as dense overflows. The dense water has been formed through a variety of processes including surface cooling, the addition of salt in the form of brine from freezing pack ice in high-latitude seas, and evaporation in enclosed subtropical seas. The dense overflows are regions of significant mixing, which modifies the temperature and salinity signal of the dense water. Many of the deep water-masses of the ocean originate in these overflows and have their properties set by the mixing that occurs therein. For example, the Nordic overflows occurring in gaps in the Greenland-Iceland-Scotland Ridge (e.g., the Denmark Straits and the Faroe Bank Channel) are the source of most of the North Atlantic Deep Water (NADW), whereas Antarctic Bottom Water (AABW) is replenished by dense overflows from the Weddell and Ross seas in the Antarctic. Together these two deep water-masses are responsible for most of the deep branches of the meridional overturning circulation (MOC). Other overflows, such as the Red Sea overflow and Mediterranean outflow, contribute to important saline waters at intermediate depths. The properties of the deep and intermediate water-masses covering much of the abyssal ocean are therefore determined to a large extent by the mixing that takes place in the overflow, and hence these localized mixing regions play a significant role in influencing the large-scale ocean circulation.
To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.