Análisis de las condiciones oceanográficas y metereológicas de la Bahía de Tumaco y su relación con eventos de escala global

Abstract

The interannual and seasonal variability of the bahía de Tumaco (Tumaco Bay) has been studíed by oceanographic and meteorological measurements, from 1999 and 1992. During this period of time, it could be determined a cycle with two well defined conditions; the first one, from February to mid- April, as a cold phase, with seawater column (0 to 100 m) temperatures between 13.6 and 26° C, the rising of the thermocline and halocline (Oto 20 m) to the surface and a higher nutrient concentraron; and the other phase, the rest of the year, with warmer waters, between 14 and 27.8° C and a deeper thermocline and halocline (30 to 50 m). This annual cycle is due the presence of the Intertropical Convergence Zone, ITCZ, at the Eastern Equatorial Pacific región, consistently with the stress of the Northeastern and Southeastern Trade Winds and its surface currents. This cycle was affected by global events, like the equatorial Kelvin waves of first baroclinique mode, during April-May, that rose the sea surface temperature, SST, the air temperature and rains; La Niña 1999-2000 event, that caused lower SST valúes (26.5° C), negative sea level anomalies and the highest nutrients concentraron of the observed time, nitrites (0.2 pM), phosphates (2pM), silica (50pM) and ammonia (4pM); and from September 2002 by El Niño event, identified by the positivesea level anomalies (more than 10cm), higher than normal rains and air temperature and the deepening of the 15°C isotherm.