Influence of the AMO and its modulation of the ENSO effects on summer precipitation in Mexican coastal regions

Abstract

Due to its geographical location and interaction with the two largest oceans, Mexico’s climate is strongly influenced by various climatic oscillations. Therefore, association studies between climatic indices and Mexico’s climate have scientific and practical importance. Teleconnection patterns have been reported between summer precipitation and various climate oscillations. For the AMO, results are not totally coincident, and modulation of ENSO effects has not been explored. Correlation analyses between AMO and ONI 3.4 with summer precipitation (June–September) at individual 203 weather stations in Mexican coastal zones were carried out, and average precipitation was compared according to AMO phases and their combinations with ENSO events. With AMO þ, it tends to rain more in northern Yucatan Peninsula, from Chiapas to Jalisco, and in the southern California Peninsula; with AMO in Tamaulipas, Sonora and northern California Peninsula. AMO modulates ENSO effects; ONI correlations pattern strengthens with AMOþ. El Niño summers are less dry with AMO on Atlantic coast, Sonora and northern California Peninsula; on Pacific coast, alternating bands are observed. With AMO, La Niña summers tend to be wetter toward south with AMOþ and toward north with AMO . These changes can be related to variations in the surface and low-level wind regimes previously reported in literature.