To understand why El Niño is frequently followed by La Niña while the opposite occurs rarely, we analyze the inherent asymmetry in a delayed negative feedback loop in the framework of delayed oscillator theory using observational data. The asymmetrical response of the ocean wave to wind is much larger than that of the wind intensity to sea surface temperature (SST) and that of the subsurface temperature to thermocline. Strong oceanic response during El Niño compared to La Niña is presumably due to the relatively shallow mean thermocline over the western Pacific, which efficiently traps the atmospheric momentum in the shallow upper ocean, and the asymmetrical wind pattern response to SST. A modified delayed oscillator model experiment verifies that the asymmetrical ocean wave response to wind is more important in the asymmetrical transition of El Niño and La Niña than asymmetrical wind intensity response to SST and asymmetrical subsurface temperature response to thermocline.
|Number of pages||8|
|Journal||Geophysical Research Letters|
|Publication status||Published - 2017 Jan 16|
Bibliographical noteFunding Information:
HS (File no. PDF/2016/000667) and AB (File no. PDF/2017/002055) acknowledge funding from Department of Science and Technology – Science and Engineering Research Board and Department of Biotechnology, Government of India for financial assistance. National Agri-Food Biotechnology Institute, Mohali is acknowledged for providing necessary facilities. We also acknowledged DBT e-Library Consortium (DeLCON), Gurugram, India for access of different journals.
©2016. American Geophysical Union. All Rights Reserved.
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)