Horizontal advection of temperature in the Drake Passage

Abstract

The balance between low‐frequency local temperature variability and geostrophic horizontal advection of temperature in the deep waters in the central Drake Passage are analyzed using a 183‐day record of moored velocity and temperature data. Geostrophic horizontal advection accounts for about 70% of the observed temperature changes during this period. If imbalances between local changes and horizontal advection were only due to vertical advection, a downward velocity of about 15 (±10) m/day is required. A daily time series of vertical velocity, calculated from these differences, indicates that vertical motions are largest during two events when cold features, possibly associated with fluctuations of the Polar Front, pass through the site.