Direct numerical simulations of diffusive staircases in the Arctic
Approved for public release, distribution unlimited === The vertical transport of heat by the diffusive layer in the Arctic thermocline is a critical element of the high-latitude climate, and yet, after decades of research, the extant estimates remain highly controversial. Laboratory-based estimates...
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Monterey, California. Naval Postgraduate School
2012
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ndltd-nps.edu-oai-calhoun.nps.edu-10945-48752014-12-04T04:08:56Z Direct numerical simulations of diffusive staircases in the Arctic Caro, Gregory P. Radko, Timour Haferman, Jeff Naval Postgraduate School (U.S.) Physical Oceanography Approved for public release, distribution unlimited The vertical transport of heat by the diffusive layer in the Arctic thermocline is a critical element of the high-latitude climate, and yet, after decades of research, the extant estimates remain highly controversial. Laboratory-based estimates of vertical heat fluxes originating from the thermohaline staircases of the thermocline are typically on the order of 0.1W/m2. This study suggests that these laboratory experiments underestimate the vertical heat fluxes and exceed their calculations by nearly an order of magnitude. We first quantify the typical density ratio, step height and temperature gradient within the diffusive staircases of the Beaufort Gyre. Then, these characteristics are used as an input into a numerical model, which simulates the vertical heat fluxes driven by the double diffusive processes. The series of two-dimensional simulation runs consistently calculated heat fluxes on the order of 1W/m2. In addition, analysis of a three-dimensional simulation suggests that the three-dimensional fluxes substantially exceed their two-dimensional counterparts. A detailed analysis of the laboratory measurements suggests that the empirical coefficients estimated scaling factors from these experiments are inconsistent with the corresponding numerical simulations. These findings suggest that laboratory derived flux laws cannot be directly applied to the Arctic Ocean and that further investigations into double-diffusive convective processes are warranted. 2012-03-14T17:43:24Z 2012-03-14T17:43:24Z 2009-03 Thesis http://hdl.handle.net/10945/4875 319535874 Monterey, California. Naval Postgraduate School |
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Approved for public release, distribution unlimited === The vertical transport of heat by the diffusive layer in the Arctic thermocline is a critical element of the high-latitude climate, and yet, after decades of research, the extant estimates remain highly controversial. Laboratory-based estimates of vertical heat fluxes originating from the thermohaline staircases of the thermocline are typically on the order of 0.1W/m2. This study suggests that these laboratory experiments underestimate the vertical heat fluxes and exceed their calculations by nearly an order of magnitude. We first quantify the typical density ratio, step height and temperature gradient within the diffusive staircases of the Beaufort Gyre. Then, these characteristics are used as an input into a numerical model, which simulates the vertical heat fluxes driven by the double diffusive processes. The series of two-dimensional simulation runs consistently calculated heat fluxes on the order of 1W/m2. In addition, analysis of a three-dimensional simulation suggests that the three-dimensional fluxes substantially exceed their two-dimensional counterparts. A detailed analysis of the laboratory measurements suggests that the empirical coefficients estimated scaling factors from these experiments are inconsistent with the corresponding numerical simulations. These findings suggest that laboratory derived flux laws cannot be directly applied to the Arctic Ocean and that further investigations into double-diffusive convective processes are warranted. |
author2 |
Radko, Timour |
author_facet |
Radko, Timour Caro, Gregory P. |
author |
Caro, Gregory P. |
spellingShingle |
Caro, Gregory P. Direct numerical simulations of diffusive staircases in the Arctic |
author_sort |
Caro, Gregory P. |
title |
Direct numerical simulations of diffusive staircases in the Arctic |
title_short |
Direct numerical simulations of diffusive staircases in the Arctic |
title_full |
Direct numerical simulations of diffusive staircases in the Arctic |
title_fullStr |
Direct numerical simulations of diffusive staircases in the Arctic |
title_full_unstemmed |
Direct numerical simulations of diffusive staircases in the Arctic |
title_sort |
direct numerical simulations of diffusive staircases in the arctic |
publisher |
Monterey, California. Naval Postgraduate School |
publishDate |
2012 |
url |
http://hdl.handle.net/10945/4875 |
work_keys_str_mv |
AT carogregoryp directnumericalsimulationsofdiffusivestaircasesinthearctic |
_version_ |
1716726570326949888 |