The role of the ENSO cycle in the modulation of moisture transport from major oceanic moisture sources

Abstract

The influence that the evolution of the ENSO cycle has on the moisture transport from the major oceanic moisture sources is investigated using a sophisticated Lagrangian approach informed by ERA-interim data, together with composites of ENSO phases. When maintaining the sources of moisture defined for the climatological period 1980-2012, the variations in the moisture sinks associated with each of these evaporative sources throughout the ENSO cycle reproduce the known patterns of variations of the large-scale atmospheric and precipitation systems over this cycle. Such variations include those observed in rainfall over the equatorial Pacific, in the major Summer monsoon systems, and in subtropical rainfall. When the areas of the sources were redefined according to the phase of ENSO, most of them remained stationary over the period of interest, nevertheless four of them showed notable differences in terms of their extents, namely the South Pacific and the Coral Sea (Pacific Ocean); the Mexican Caribbean (Atlantic), and the Arabian Sea (Indian). Key Points ENSO modulates the transport of moisture from the major oceanic sources Coherence with variations of the large-scale atmospheric and precipitation systems Most of moisture sources keep position and extension stationary along the ENSO cycle © 2014. American Geophysical Union. All Rights Reserved.