outstanding problem in the oceanic sciences is the rate of heat
and freshwater transport from the equator to the poles, for it
is this transport which powers the Earth's weather and climate
system." Keffer and Holloway, Nature (1988). MOCHA is a
collaborative project, partnered with the UK RAPID Program, to
measure the meridional overturning circulation (MOC) and ocean
heat transport in the North Atlantic Ocean (Figure 1). These
transports are primarily associated with the Thermohaline
Circulation. Simply put, warm waters move poleward at the
surface of the ocean, where they cool and sink, to return
equatorward in the deep ocean. Figure 1. A schematic for the
North Atlantic Overturning (click on the image for details,
courtesy of RAPID/NERC) models suggest that the MOC in the
Atlantic, and the accompanying oceanic heat flux, vary
considerably on interannual time scales. In addition to abrupt
climate change scenarios in which the MOC can virtually shut off
(Manabe and Stouffer, 1993; Vellinga and Wood, 2002),