SEMINAR: special MPO seminar Friday

[Brian Mapes <bmapes@rsmas.miami.edu>]

Special MPO SEMINAR

Gregory C. Johnson

NOAA/PMEL and University of Washington

“Recent Warming (and Freshening) of Antarctic Bottom Water”

Special time and room: Friday, Jan 22, 2009 - 2:00pm
MSC 343 classroom

Abstract:  Waters of Antarctic origin play a large role in the global meridional overturning circulation. These waters dominate the abyss and ventilate a significant fraction of the entire global ocean.   Hydrographic sections occupied mostly in the 1990’s during the World Ocean Circulation Experiment (WOCE) provided a high-accuracy near-global survey of ocean water properties.  A subset of these sections has been reoccupied in the current decade by international repeat hydrography programs in support of CLIVAR and CO2 studies.  Comparison of these repeat sections reveals statistically significant warming in abyssal waters around various parts of the globe over the past decade. Warming is generally largest close to the Antarctic source regions, but can be traced at least to the equator in the Atlantic, and even the North Pacific Ocean.  Abyssal freshening has also been observed with repeat section data in more limited regions around Antarctica over the past few decades.  We estimate the potential contribution of the observed warming to global heat and sea level budgets.