An ENSO signal in the North Atlantic subtropical area

Precipitation in the Canary Islands is studied from a synoptic point of view for the 1955-1998 period, using data from the NCEP-NCAR reanalysis. The use of automatic objective techniques allows the identification of five patterns leading to precipitation in the area. The influence of intense El Ni (n) over tildeo and La Ni (n) over tildea events on these patterns is then studied. The results show that La Ni (n) over tildea conditions are characterized by more intense and frequent precipitation episodes as result of deeper and more frequent geopotential anomalies at the 500 hPa level.