Tehuantepec Wind and Pressure Changes Associated with Tropical Cyclones (Formerly Paper Number 2.4)

SeaWinds on QuikSCAT observations provide high temporal and spatial resolution wind fields, which are used to examine gap flow through the Chivela Pass and the influence of Tropical Cyclones (TCs). This outflow can extend several thousand kilometers, and has an influence on the generation of ocean eddies. TCs in the Caribbean Sea have been shown to alter the strength and direction of the jet outflow, despite the intervening mountain range. Most previous studies of this gap flow have used monthly averages of sparse ship observations, ECMWF fields, mesoscale models, or proxies such as cloud motion or sea surface temperatures (SSTs). Recently, remotely sensed winds from NSCAT provided insights on finer space and time scales. SeaWinds provides (over ocean) vector surface winds unprecedented accuracy (uncertainties of 0.45 m s^-1 and 5°), with an average of twice daily observations. The observations show that the gap flow often turns to the right (dominated by the Coriolis force); however, TCs can cause highly non-inertial flow for several days. The QuikSCAT observations have the spatial and temporal resolution required to show the evolution of the gap outflow and the modification due to TCs. These surface winds are also used to estimate surface pressure gradients. The impacts of TCs on surface winds and pressures are examined.