scholarly journals Ocean salinity indices of interannual modes in the tropical Pacific

2021 ◽  
Author(s):  
Jianwei Chi ◽  
Tangdong Qu ◽  
Yan Du ◽  
Jifeng Qi ◽  
Ping Shi
Keyword(s):  
Global Warming ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Eastern Pacific ◽  
Dipole Mode ◽  
Eastern Tropical Pacific ◽  
Central Pacific El Niño ◽  
Eastern Pacific El Niño ◽  
The Tropical Pacific

AbstractThis study investigates the interannual modes of the tropical Pacific using salinity from observations, ocean reanalysis output and CMIP6 products. Here we propose two indices of sea surface salinity (SSS), a monopole mode and a dipole mode, to identify the El Niño—South Oscillation (ENSO) and its diversity, respectively. The monopole mode is primarily controlled by atmospheric forcing, namely, the enhanced precipitation that induces negative SSS anomalies across nearly the entire tropical Pacific. The dipole mode is mainly forced by oceanic dynamics, with zonal current transporting fresh water from the western fresh pool into the western-central and salty water from the subtropics into the eastern tropical Pacific. Under a global warming condition, an increase in the monopole and dipole mode variance indicates an increase in both the central and eastern Pacific El Niño variability. The increase in central Pacific El Niño variability is largely due to enhanced vertical stratification during global warming in the upper layer, with intensified zonal advection. An eastern Pacific El Niño-like warming pattern contributes to the increase in eastern Pacific El Niño, with enhanced precipitation over the central-eastern tropical Pacific.

Salinity variability in the tropical Pacific during the Central-Pacific and Eastern-Pacific El Niño events

2019 ◽  
Vol 199 ◽  
pp. 103225 ◽  
Author(s):  
Jifeng Qi ◽  
Linlin Zhang ◽  
Tangdong Qu ◽  
Baoshu Yin ◽  
Zhenhua Xu ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Eastern Pacific ◽  
Central Pacific ◽  
Eastern Pacific El Niño ◽  
Salinity Variability ◽  
El Niño Events ◽  
El Nino Events ◽  
The Tropical Pacific

scholarly journals A Simple Analytical Model for Understanding the Formation of Sea Surface Temperature Patterns under Global Warming*

2014 ◽  
Vol 27 (22) ◽  
pp. 8413-8421 ◽  
Author(s):  
Lei Zhang ◽  
Tim Li
Keyword(s):  
Global Warming ◽  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Sea Surface ◽  
The Tropics ◽  
The Tropical Pacific

Abstract How sea surface temperature (SST) changes under global warming is critical for future climate projection because SST change affects atmospheric circulation and rainfall. Robust features derived from 17 models of phase 5 of the Coupled Model Intercomparison Project (CMIP5) include a much greater warming in high latitudes than in the tropics, an El Niño–like warming over the tropical Pacific and Atlantic, and a dipole pattern in the Indian Ocean. However, the physical mechanism responsible for formation of such warming patterns remains open. A simple theoretical model is constructed to reveal the cause of the future warming patterns. The result shows that a much greater polar, rather than tropical, warming depends primarily on present-day mean SST and surface latent heat flux fields, and atmospheric longwave radiation feedback associated with cloud change further enhances this warming contrast. In the tropics, an El Niño–like warming over the Pacific and Atlantic arises from a similar process, while cloud feedback resulting from different cloud regimes between east and west ocean basins also plays a role. A dipole warming over the equatorial Indian Ocean is a response to weakened Walker circulation in the tropical Pacific.

The impact of global warming on the tropical Pacific Ocean and El Niño

2010 ◽  
Vol 3 (6) ◽  
pp. 391-397 ◽  
Author(s):  
Mat Collins ◽  
Soon-Il An ◽  
Wenju Cai ◽  
Alexandre Ganachaud ◽  
Eric Guilyardi ◽  
...  
Keyword(s):  
Global Warming ◽  
Pacific Ocean ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Tropical Pacific Ocean ◽  
The Impact ◽  
The Tropical Pacific

scholarly journals Intensification of El Niño Rainfall Variability Over the Tropical Pacific in the Slow Oceanic Response to Global Warming

2019 ◽  
Vol 46 (4) ◽  
pp. 2253-2260 ◽  
Author(s):  
Xiao‐Tong Zheng ◽  
Chang Hui ◽  
Shang‐Ping Xie ◽  
Wenju Cai ◽  
Shang‐Min Long
Keyword(s):  
Global Warming ◽  
El Niño ◽  
El Nino ◽  
Rainfall Variability ◽  
Tropical Pacific ◽  
Oceanic Response ◽  
The Tropical Pacific

scholarly journals A review of ENSO theories

2018 ◽  
Vol 5 (6) ◽  
pp. 813-825 ◽  
Author(s):  
Chunzai Wang
Keyword(s):  
El Niño ◽  
El Nino ◽  
Enso Event ◽  
Tropical Pacific ◽  
Kelvin Waves ◽  
Western Pacific ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Negative Feedbacks ◽  
The Tropical Pacific

Abstract The El Niño and the Southern Oscillation (ENSO) occurrence can be usually explained by two views of (i) a self-sustained oscillatory mode and (ii) a stable mode interacting with high-frequency forcing such as westerly wind bursts and Madden-Julian Oscillation events. The positive ocean–atmosphere feedback in the tropical Pacific hypothesized by Bjerknes leads the ENSO event to a mature phase. After ENSO event matures, negative feedbacks are needed to cease the ENSO anomaly growth. Four negative feedbacks have been proposed: (i) reflected Kelvin waves at the ocean western boundary, (ii) a discharge process due to Sverdrup transport, (iii) western-Pacific wind-forced Kelvin waves and (iv) anomalous zonal advections and wave reflection at the ocean eastern boundary. These four ENSO mechanisms are respectively called the delayed oscillator, the recharge–discharge oscillator, the western-Pacific oscillator and the advective–reflective oscillator. The unified oscillator is developed by including all ENSO mechanisms, i.e. all four ENSO oscillators are special cases of the unified oscillator. The tropical Pacific Ocean and atmosphere interaction can also induce coupled slow westward- and eastward-propagating modes. An advantage of the coupled slow modes is that they can be used to explain the propagating property of interannual anomalies, whereas the oscillatory modes produce a standing oscillation. The research community has recently paid attention to different types of ENSO events by focusing on the central-Pacific El Niño. All of the ENSO mechanisms may work for the central-Pacific El Niño events, with an addition that the central-Pacific El Niño may be related to forcing or processes in the extra-tropical Pacific.

scholarly journals Disentangling the Impact of ENSO and Indian Ocean Variability on the Regional Climate of Bangladesh: Implications for Cholera Risk

2010 ◽  
Vol 23 (10) ◽  
pp. 2817-2831 ◽  
Author(s):  
Benjamin A. Cash ◽  
Xavier Rodó ◽  
James L. Kinter ◽  
Md Yunus
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Summer Precipitation ◽  
Tropical Pacific ◽  
Eastern Tropical Pacific ◽  
El Niño Events ◽  
Sst Anomalies ◽  
El Nino Events ◽  
The Tropical Pacific

Abstract Recent studies arising from both statistical analysis and dynamical disease models indicate that there is a link between the incidence of cholera, a paradigmatic waterborne bacterial illness endemic to Bangladesh, and the El Niño–Southern Oscillation (ENSO). Cholera incidence typically increases following boreal winter El Niño events for the period 1973–2001. Observational and model analyses find that Bangladesh summer rainfall is enhanced following winter El Niño events, providing a plausible physical link between El Niño and cholera incidence. However, rainfall and cholera incidence do not increase following every winter El Niño event. Substantial variations in Bangladesh precipitation also occur in simulations in which identical sea surface temperature (SST) anomalies are prescribed in the central and eastern tropical Pacific. Bangladesh summer precipitation is thus not uniquely determined by forcing from the tropical Pacific, with significant implications for predictions of cholera risk. Nonparametric statistical analysis is used to identify regions of SST anomalies associated with variations in Bangladesh rainfall in an ensemble of pacemaker simulations. The authors find that differences in the response of Bangladesh summer precipitation to winter El Niño events are strongly associated with the persistence of warm SST anomalies in the central Pacific. Also there are significant differences in the SST patterns associated with positive and negative Bangladesh rainfall anomalies, indicating that the response is not fully linear. SST anomalies in the Indian Ocean also modulate the influence of the tropical Pacific, with colder Indian Ocean SST tending to enhance Bangladesh precipitation relative to warm Indian Ocean SST for identical conditions in the central and eastern tropical Pacific. This influence is not fully linear. Forecasts of Bangladesh rainfall and cholera risk may thus be improved by considering the Niño-3 and Niño-4 indices separately, rather than the Niño-3.4 index alone. Additional skill may also be gained by incorporating information on the southeast Indian Ocean and by updating the forecast with information on the evolution of the SST anomalies into spring.

Response of the tropical Pacific Ocean to El Niño versus global warming

2016 ◽  
Vol 48 (3-4) ◽  
pp. 935-956 ◽  
Author(s):  
Fukai Liu ◽  
Yiyong Luo ◽  
Jian Lu ◽  
Xiuquan Wan
Keyword(s):  
Global Warming ◽  
Pacific Ocean ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Tropical Pacific Ocean ◽  
The Tropical Pacific

scholarly journals A Precursory Signal of the Central Pacific El Niño Event: Eastern Pacific Cooling Mode

2021 ◽  
Author(s):  
Tao Lingjiang ◽  
Duan Wansuo
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Cooling Mode ◽  
Central Pacific El Niño ◽  
Climate Effect ◽  
Cp El Niño ◽  
El Niño Event ◽  
Basin Scale ◽  
The Tropical Pacific

Abstract In recent decades, the tropical Pacific frequently experiences a new type of El Niño with warming center in the central tropical Pacific (i.e., the CP-El Niño) with distinct global climate effect to the traditional El Niño (i.e., EP-El Niño). Predicting the El Niño diversity is still a huge challenge for climatologists partly due to the precursory signals of El Niño events with different type is unclear. In the present study, a novel precursory signal that presents a negative sea surface temperature anomaly in the eastern tropical Pacific (i.e., EP-cooling mode) is revealed, which tends to evolve into a CP-El Niño event. The transition from the EP-cooling mode to CP-El Niño is explained by the basin-scale air-sea coupling in the tropical Pacific and teleconnections between the tropical and North Pacific. With the EP-cooling mode as a predictor, the forecast skill for the CP-El Niño in hindcast experiments is obviously improved by using regression models. The results in the present study are therefore instructive for promoting a better understanding of El Niño diversity and predictability.

Understanding the El Niño-like oceanic response in the tropical Pacific to global warming

2014 ◽  
Vol 45 (7-8) ◽  
pp. 1945-1964 ◽  
Author(s):  
Yiyong Luo ◽  
Jian Lu ◽  
Fukai Liu ◽  
Wei Liu
Keyword(s):  
Global Warming ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Oceanic Response ◽  
The Tropical Pacific
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