RESEARCH - North Atlantic Subtropical Mode Water

North Atlantic subtropical mode water, or Eighteen Degree Water (EDW), is an upper ocean water mass characterized by homogenous physical and chemical properties. It is formed during winter and early spring south of the Gulf Stream due to large heat loss to the atmosphere that triggers vigorous convective mixing and deepening of the mixed layer. The physical dynamics of this process is studied by the CLIMODE group. EDW formation is also of interest to biogeochemists, as the carbon inventory is modified due to air-sea CO2 exchange, mixing and biological processes during formation, and is also further modified as the water disperses laterally throughout the subtropical gyre. Some of the questions we are working on include:

Video taken from R/V Knorr in March of 2007 showing conditions characteristic for the Gulf Stream region during winter/spring, i.e., gray skies, cold, windy, and wavy. Note the “steaming” of the breaking waves, which is facilitated by the large temperature gradient between the water (~20°C) and the air (~0°C).