On the variability of ozone in the equatorial eastern Pacific boundary layer

The first campaign, Primera Investigacion sobre la Quimica, Evolucion y Reparto de Ozono, was carried out from September 2000 to July 2002. The second study, Climate and HAlogen Reactivity tropicaL EXperiment, was conducted from September 2010 to March 2012.

These measurements complement the Southern Hemisphere ADditional OZonesonde observations made with weekly to monthly frequency at Galapagos. In this work, the daily, intraseasonal, seasonal and interannual variability of O-3 in the marine boundary layer are described and compared to those observed in other tropical locations. The O-3 diurnal cycle shows two regimes: (i) photochemical destruction followed by nighttime recovery in the cold season (July to November) and (ii) daytime advection and photochemical loss followed by nighttime depositional loss associated to windless conditions in the warm season (February to April).