Ship Observations of the Tropical Pacific Ocean along the Coast of South America

Abstract

Abstract In October 2007 the NOAA ship Ronald H. Brown sailed southward within 300 km of the coast of Ecuador and Peru, sampling surface meteorology, air–sea turbulent and radiative fluxes, cloud properties, and upper-air soundings from the equator to 20°S. Two distinct water masses characterize the coastal region: cold-pool water below 19°C in the Southern Hemisphere, and warm-pool water above 20°C to the north, with a transition between the water masses at 2.5°S. Net turbulent and radiative fluxes warm the cool water south of 2.5°S by 100 W m−2 but do not warm the equatorial water significantly. Winds blow parallel to the shore, about 5 m s−1 over the cold pool and 7 m s−1 over the equator. Stratocumulus clouds are remarkably solid over the coastal cold pool, with only brief periods of partial clearing, mostly in the afternoon. Lower aerosol concentrations and thicker clouds observed farther from the coast on 22–23 October are coincident with a pocket of open cells seen to the west and southwest of the ship. Observations from this cruise and other NOAA Stratus cruises (2001 and 2003–07) are suitable for comparison with model simulations and provide context for future field experiments. These datasets are publicly available.