Supplement to Ocean Climate Observations and Analyses (2012-2013)

The Woods Hole Oceanographic Institution (WHOI) Ocean Reference Station project is carried
out to provide critical, sustained observations of a key region of the ocean – the trade wind
region. As the earth sits in space, sunlight heats the earth in a broad, equatorial region. The
ocean and atmosphere both are driven by the thermal gradients between the equator and the
poles; the oceans, with their ability to store, transport, and release heat and moisture to the
atmosphere, play an important role in weather and climate. Air that is heated rises at the equator
and descends in the subtropics, resulting in broad regions of winds flowing from the east to the
equator. Around the globe these easterly trade wind regions cover roughly 50% of the ocean
surface, in a wide belt spanning the equator. These regions are where the equatorial
concentration of solar heating leads to net ocean heating and where in turn large evaporation and accompanying latent heat flux provides energy and moisture to drive the atmosphere over a range of scales, from the general Hadley circulation that is the source of the trade winds down to
intense hurricanes intensified by that heat and moisture. They are also where the ocean provides
CO2 to the atmosphere in contrast to the higher latitudes where the ocean gains CO2 from the
atmosphere. Integrated across the expanse of the trade wind regions, errors and uncertainties in
the exchange of heat, freshwater, momentum, and compounds such as CO2, can challenge our
ability to understand the way in which the atmosphere and ocean interact and how that interaction should be represented in models used to predict weather and climate variability.