Understanding changing ENSO flavors in the mid-Holocene laboratory.

University Of Hawaii, Honolulu

Investigators

Abstract

El Niño/Southern Oscillation (ENSO) events can have profound impacts on regional climate in many parts of the world. Recent studies have shown that two primary "flavors" of El Niño exist, with distinct intensities and sea-surface temperature (SST) patterns: the Eastern Pacific El Niño, which is more intense, with warmer SSTs concentrated in the eastern Pacific; and the Central Pacific El Niño, which is more moderate, with warmer SSTs concentrated in the central Pacific. Neither models nor observations conclusively indicate which of these ENSO flavors will be dominant as greenhouse gas warming progresses, creating uncertainty in projections of regional climate change throughout the Pacific basin. To help address this uncertainty, a team of scientists from the University of Hawaii will undertake a paleoclimate reconstruction study focusing on understanding the response of ENSO flavors to climate conditions in the mid-Holocene (approximately 5000-7000 years before present). Through a synthesis of climate model results and paleoclimate proxies, the project will investigate the origin of ENSO flavors and their sensitivity to changes in tropical climate. In addition, modeling experiments will be performed to examine the role of stochastic noise in ENSO response to climate change. This research will advance the understanding of ENSO behavior under past climate conditions, leading to better-constrained models of future climate change in the tropics. The project will support two early-career scientists.