skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Changes in ENSO amplitude under climate warming and cooling

Abstract

The response of ENSO amplitude to climate warming and cooling is investigated using the Community Earth System Model (CESM), in which the warming and cooling scenarios are designed by adding heat fluxes of equal amplitude but opposite sign onto the ocean surface, respectively. Results show that the warming induces an increase of the ENSO amplitude but the cooling gives rise to a decrease of the ENSO amplitude, and these changes are robust in statistics. A mixed layer heat budget analysis finds that the increasing (decreasing) SST tendency under climate warming (cooling) is mainly due to an enhancement (weakening) of dynamical feedback processes over the equatorial Pacific, including zonal advective (ZA) feedback, meridional advective (MA) feedback, thermocline (TH) feedback, and Ekman (EK) feedback. As the climate warms, a wind anomaly of the same magnitude across the equatorial Pacific can induce a stronger zonal current change in the east (i.e., a stronger ZA feedback), which in turn produces a greater weakening of upwelling (i.e., a stronger EK feedback) and thus a larger thermocline change (i.e., a stronger TH feedback). In response to the climate warming, in addition, a slowdown of the subtropical cells (STCs) will result in a narrower meridional width ofmore » SST anomaly around the equator and thus a stronger MA feedback. And vice versa for the cooling case. Bjerknes linear stability (BJ) index is also evaluated for the linear stability of ENSO, with significantly larger (smaller) BJ index found for the warming (cooling) case.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1507353
Report Number(s):
PNNL-SA-130743
Journal ID: ISSN 0930-7575
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Climate Dynamics
Additional Journal Information:
Journal Volume: 52; Journal Issue: 3-4; Journal ID: ISSN 0930-7575
Publisher:
Springer-Verlag
Country of Publication:
United States
Language:
English
Subject:
ENSO amplitude, Climate Warming, Climate cooling, Dynamical feedbacks

Citation Formats

Wang, Yingying, Luo, Yiyong, Lu, Jian, and Liu, Fukai. Changes in ENSO amplitude under climate warming and cooling. United States: N. p., 2018. Web. doi:10.1007/s00382-018-4224-1.
Wang, Yingying, Luo, Yiyong, Lu, Jian, & Liu, Fukai. Changes in ENSO amplitude under climate warming and cooling. United States. doi:10.1007/s00382-018-4224-1.
Wang, Yingying, Luo, Yiyong, Lu, Jian, and Liu, Fukai. Tue . "Changes in ENSO amplitude under climate warming and cooling". United States. doi:10.1007/s00382-018-4224-1.
@article{osti_1507353,
title = {Changes in ENSO amplitude under climate warming and cooling},
author = {Wang, Yingying and Luo, Yiyong and Lu, Jian and Liu, Fukai},
abstractNote = {The response of ENSO amplitude to climate warming and cooling is investigated using the Community Earth System Model (CESM), in which the warming and cooling scenarios are designed by adding heat fluxes of equal amplitude but opposite sign onto the ocean surface, respectively. Results show that the warming induces an increase of the ENSO amplitude but the cooling gives rise to a decrease of the ENSO amplitude, and these changes are robust in statistics. A mixed layer heat budget analysis finds that the increasing (decreasing) SST tendency under climate warming (cooling) is mainly due to an enhancement (weakening) of dynamical feedback processes over the equatorial Pacific, including zonal advective (ZA) feedback, meridional advective (MA) feedback, thermocline (TH) feedback, and Ekman (EK) feedback. As the climate warms, a wind anomaly of the same magnitude across the equatorial Pacific can induce a stronger zonal current change in the east (i.e., a stronger ZA feedback), which in turn produces a greater weakening of upwelling (i.e., a stronger EK feedback) and thus a larger thermocline change (i.e., a stronger TH feedback). In response to the climate warming, in addition, a slowdown of the subtropical cells (STCs) will result in a narrower meridional width of SST anomaly around the equator and thus a stronger MA feedback. And vice versa for the cooling case. Bjerknes linear stability (BJ) index is also evaluated for the linear stability of ENSO, with significantly larger (smaller) BJ index found for the warming (cooling) case.},
doi = {10.1007/s00382-018-4224-1},
journal = {Climate Dynamics},
issn = {0930-7575},
number = 3-4,
volume = 52,
place = {United States},
year = {2018},
month = {5}
}