Interannual climate variability over Mexico, Central America and Caribbean is modulated to a large extent by the presence of warm pools, one over the Intra America Seas and one off the Mexican Pacific coast. Summer rain over this region exhibits maxima during June and September-October and relative minimum during July and August, known as the midsummer drought (MSD). Magaña et al. (1999) have proposed that air sea interaction processes over Mexican warm pool result in such relative minimum in the middle rainy season.

In order to test the hypothesis about the Mid Summer Drought (MSD) in Mesoamerica and more generally examine the physical mechanisms that control climate variability of the region a field experiment known as ECAC (Climate Experiment in the Americas Warm Pools) took place during 2001 boreal summer. Four oceanographic/meteorological campaigns were conducted, three in the northeastern Pacific and one in the Caribbean Sea. The main objective during the campaigns is to monitor the atmospheric and oceanographic factors considered crucial in the summer rains.

Some ECAC preliminary results are presented with special emphasis on the observed conditions during campaigns and future researches are also discussed. It is worth to mention that from the socioeconomic point of view, the various countries in this region share a common cultural background and exhibit similar levels of vulnerability to extreme climate conditions. Therefore, an important element of the present study is that the results may be used in potential adaptation measures.