scholarly journals The potential influence of falling ice radiative effects on Central-Pacific El Niño variability under progressive global warming

2021 ◽  
Author(s):  
Li-Chiao Wang ◽  
Juilin Li ◽  
Kuan-Man Xu ◽  
Lan Thi Dao ◽  
Wei-Liang Lee ◽  
...  
Keyword(s):  
Life Cycle ◽  
El Niño ◽  
El Nino ◽  
Surface Wind ◽  
Cmip5 Models ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Cp El Niño ◽  
Surface Wind Stress ◽  
Sst Anomalies

Abstract The impacts of falling ice (snow) radiative effects (FIREs) on simulated surface wind stress and sea surface temperature (SST) in Central Pacific El Niño (CP-El Niño) under a progressive warming climate are examined. Using controlled simulations with the CESM1 model, it is shown that the exclusion of FIREs (No snow: NOS) generates persistent westerly anomalies in surface wind stress relative to that with FIREs (Snow on: SON). These anomalies subsequently lead to a weakening of the easterly trade winds associated with warmer SST anomalies in modeled life cycle. Results over three separated 40-year intervals (P1: 21-60 years; P2: 61-100 years; P3: 101-140 years) are compared with Coupled Model Intercomparison Project phase 5 (CMIP5) models without FIREs. Both NOS configuration and CMIP5 models simulate longer life cycles of CP-El Niño events with weakening easterlies and warmer SST anomalies on the equator, persistently propagating eastward from the mature to dissipating phases. Compared to NOS, SON, on the other hand, produces a shorter CP-El Niño life cycle together with stronger easterlies and colder SSTs over the eastern to central equatorial Pacific. The magnitudes of the simulated westerlies and warm SST anomalies tend to diminish without eastward shifting following the peak of the CP-El Niño activity. There are substantial differences in CP-El Niño characteristics from P1 to P3 between NOS and SON. During P1, both SON and NOS show patterns which are consistent with their present-day counterparts. In P2 and P3, SON exhibits a prolonged CP-El Niño life cycle, while NOS develops a double-peak El Niño evolution at the mature and decaying phases. Regarding El Niño diversity and the projections, the CMIP5 models have not reached a consensus. The inclusion of the FIREs would increase the confidence in simulating El Niño future behavior.

scholarly journals The Annual-Cycle Modulation of Meridional Asymmetry in ENSO’s Atmospheric Response and Its Dependence on ENSO Zonal Structure

2015 ◽  
Vol 28 (14) ◽  
pp. 5795-5812 ◽  
Author(s):  
Wenjun Zhang ◽  
Haiyan Li ◽  
Fei-Fei Jin ◽  
Malte F. Stuecker ◽  
Andrew G. Turner ◽  
...  
Keyword(s):  
Annual Cycle ◽  
El Niño ◽  
El Nino ◽  
Warm Pool ◽  
Atmospheric Response ◽  
Central Pacific ◽  
Cp El Niño ◽  
El Niño Events ◽  
Sst Anomalies ◽  
El Nino Events

Abstract Previous studies documented that a distinct southward shift of central Pacific low-level wind anomalies occurring during the ENSO decaying phase is caused by an interaction between the western Pacific annual cycle and El Niño–Southern Oscillation (ENSO) variability. The present study finds that the meridional movement of the central Pacific wind anomalies appears only during traditional eastern Pacific El Niño (EP El Niño) events rather than in central Pacific El Niño (CP El Niño) events in which sea surface temperature (SST) anomalies are confined to the central Pacific. The zonal structure of ENSO-related SST anomalies therefore has an important effect on meridional asymmetry in the associated atmospheric response and its modulation by the annual cycle. In contrast to EP El Niño events, the SST anomalies of CP El Niño events extend farther west toward the warm pool region with its climatological warm SSTs. In the warm pool region, relatively small SST anomalies are thus able to excite convection anomalies on both sides of the equator, even with a meridionally asymmetric SST background state. Therefore, almost meridionally symmetric precipitation and wind anomalies are observed over the central Pacific during the decaying phase of CP El Niño events. The SST anomaly pattern of La Niña events is similar to CP El Niño events with a reversed sign. Accordingly, no distinct southward displacement of the atmospheric response occurs over the central Pacific during the La Niña decaying phase. These results have important implications for ENSO climate impacts over East Asia, since the anomalous low-level anticyclone over the western North Pacific is an integral part of the annual cycle–modulated ENSO response.

scholarly journals Northern Hemisphere Stratospheric Pathway of Different El Niño Flavors in Stratosphere-Resolving CMIP5 Models

2017 ◽  
Vol 30 (12) ◽  
pp. 4351-4371 ◽  
Author(s):  
N. Calvo ◽  
M. Iza ◽  
M. M. Hurwitz ◽  
E. Manzini ◽  
C. Peña-Ortiz ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
El Niño ◽  
El Nino ◽  
Cmip5 Models ◽  
Eastern Canada ◽  
Central Pacific ◽  
Cp El Niño ◽  
El Niño Events ◽  
Ep El Niño ◽  
El Nino Events

The Northern Hemisphere (NH) stratospheric signals of eastern Pacific (EP) and central Pacific (CP) El Niño events are investigated in stratosphere-resolving historical simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5), together with the role of the stratosphere in driving tropospheric El Niño teleconnections in NH climate. The large number of events in each composite addresses some of the previously reported concerns related to the short observational record. The results shown here highlight the importance of the seasonal evolution of the NH stratospheric signals for understanding the EP and CP surface impacts. CMIP5 models show a significantly warmer and weaker polar vortex during EP El Niño. No significant polar stratospheric response is found during CP El Niño. This is a result of differences in the timing of the intensification of the climatological wavenumber 1 through constructive interference, which occurs earlier in EP than CP events, related to the anomalous enhancement and earlier development of the Pacific–North American pattern in EP events. The northward extension of the Aleutian low and the stronger and eastward location of the high over eastern Canada during EP events are key in explaining the differences in upward wave propagation between the two types of El Niño. The influence of the polar stratosphere in driving tropospheric anomalies in the North Atlantic European region is clearly shown during EP El Niño events, facilitated by the occurrence of stratospheric summer warmings, the frequency of which is significantly higher in this case. In contrast, CMIP5 results do not support a stratospheric pathway for a remote influence of CP events on NH teleconnections.

scholarly journals Simple dynamical models capturing the key features of the Central Pacific El Niño

2016 ◽  
Vol 113 (42) ◽  
pp. 11732-11737 ◽  
Author(s):  
Nan Chen ◽  
Andrew J. Majda
Keyword(s):  
El Niño ◽  
El Nino ◽  
Coupled Model ◽  
Walker Circulation ◽  
Coupled System ◽  
Trade Wind ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Cp El Niño ◽  
Ocean Processes

The Central Pacific El Niño (CP El Niño) has been frequently observed in recent decades. The phenomenon is characterized by an anomalous warm sea surface temperature (SST) confined to the central Pacific and has different teleconnections from the traditional El Niño. Here, simple models are developed and shown to capture the key mechanisms of the CP El Niño. The starting model involves coupled atmosphere–ocean processes that are deterministic, linear, and stable. Then, systematic strategies are developed for incorporating several major mechanisms of the CP El Niño into the coupled system. First, simple nonlinear zonal advection with no ad hoc parameterization of the background SST gradient is introduced that creates coupled nonlinear advective modes of the SST. Secondly, due to the recent multidecadal strengthening of the easterly trade wind, a stochastic parameterization of the wind bursts including a mean easterly trade wind anomaly is coupled to the simple atmosphere–ocean processes. Effective stochastic noise in the wind burst model facilitates the intermittent occurrence of the CP El Niño with realistic amplitude and duration. In addition to the anomalous warm SST in the central Pacific, other major features of the CP El Niño such as the rising branch of the anomalous Walker circulation being shifted to the central Pacific and the eastern Pacific cooling with a shallow thermocline are all captured by this simple coupled model. Importantly, the coupled model succeeds in simulating a series of CP El Niño that lasts for 5 y, which resembles the two CP El Niño episodes during 1990–1995 and 2002–2006.

Seasonal rainfall variability in Korea within the context of different evolution patterns of the central Pacific El Niño

2016 ◽  
Vol 8 (3) ◽  
pp. 412-422 ◽  
Author(s):  
Jong-Suk Kim ◽  
Chan-Young Son ◽  
Young-Il Moon ◽  
Joo-Heon Lee
Keyword(s):  
El Niño ◽  
Korean Peninsula ◽  
Heavy Rainfall ◽  
El Nino ◽  
Seasonal Rainfall ◽  
Extreme Weather Events ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Cp El Niño ◽  
Starting Point

This study aims to identify how different evolution patterns of the central Pacific (CP) El Niño influence seasonal rainfall and intense rainfall occurrence in Korea. The results suggest that changes in the CP El Niño can influence the spatiotemporal patterns of seasonal and heavy rainfall over East Asia. Specifically, for the Korean Peninsula, rainfall was typically lower during the years with the abrupt-decaying and prolonged-decaying CP El Niño evolution patterns. During the symmetric-decaying years, more rainfall occurred over the Korean Peninsula, and heavy rainfall events were concentrated in the central regions. Hence, flooding poses a risk to the Korean Peninsula and such risks may be heightened during symmetric-decaying CP El Niño years. Although this study relies on relatively short-term observation events and samples, the results provide a starting point for a more detailed examination of the large-scale and local factors for developing adaptive strategies to protect water resources and to plan for extreme weather events in a changing climate.

scholarly journals Impact of Eastern and Central Pacific El Niño on Lower Tropospheric Ozone in China

2022 ◽  
Author(s):  
Zhongjing Jiang ◽  
Jing Li
Keyword(s):  
El Niño ◽  
Tropospheric Ozone ◽  
El Nino ◽  
Southern China ◽  
Anthropogenic Activities ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Cp El Niño ◽  
Budget Analysis ◽  
Ep El Niño

Abstract. Tropospheric ozone is an essential atmospheric component as it plays a significant role in influencing radiation equilibrium and ecological health. It is affected not only by anthropogenic activities but also by natural climate variabilities. Here we examine the tropospheric ozone change in China associated with the Eastern Pacific (EP) and Central Pacific (CP) El Niño using satellite observations from 2007 to 2017 and GEOS-Chem simulations from 1980 to 2017. GEOS-Chem simulations reasonably reproduce the satellite-retrieved lower tropospheric ozone (LTO) changes despite a slight underestimation. Results show that El Niño generally exerts negative impacts on LTO concentration in China, except for southeastern China during the pre-CP El Niño autumn and post-EP El Niño summer. The budget analysis further indicates that for both events, LTO changes are dominated by the transport process controlled by circulation patterns and the chemical process influenced by local meteorological anomalies associated with El Niño, especially the solar radiation and relative humidity changes. The differences between EP and CP-induced LTO changes mostly lie in southern China. The different strengths, positions, and duration of western North Pacific anomalous anticyclone (WNPAC) induced by tropical warming are likely responsible for the different EP and CP LTO changes. During the post-EP El Niño summer, the Indian ocean capacitor also plays an important role in controlling LTO changes over southern China.

scholarly journals Changes in Independency between Two Types of El Niño Events under a Greenhouse Warming Scenario in CMIP5 Models

2015 ◽  
Vol 28 (19) ◽  
pp. 7561-7575 ◽  
Author(s):  
Yoo-Geun Ham ◽  
Yerim Jeong ◽  
Jong-Seong Kug
Keyword(s):  
Global Warming ◽  
El Niño ◽  
El Nino ◽  
Western Pacific ◽  
Cmip5 Models ◽  
Greenhouse Warming ◽  
Central Pacific ◽  
El Niño Events ◽  
The Western Pacific ◽  
El Nino Events

Abstract This study uses archives from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to investigate changes in independency between two types of El Niño events caused by greenhouse warming. In the observations, the independency between cold tongue (CT) and warm pool (WP) El Niño events is distinctively increased in recent decades. The simulated changes in independency between the two types of El Niño events according to the CMIP5 models are quite diverse, although the observed features are simulated to some extent in several climate models. It is found that the climatological change after global warming is an essential factor in determining the changes in independency between the two types of El Niño events. For example, the independency between these events is increased after global warming when the climatological precipitation is increased mainly over the equatorial central Pacific. This climatological precipitation increase extends convective response to the east, particularly for CT El Niño events, which leads to greater differences in the spatial pattern between the two types of El Niño events to increase the El Niño independency. On the contrary, in models with decreased independency between the two types of El Niño events after global warming, climatological precipitation is increased mostly over the western Pacific. This confines the atmospheric response to the western Pacific in both El Niño events; therefore, the similarity between them is increased after global warming. In addition to the changes in the climatological state after global warming, a possible connection of the changes in the El Niño independency with the historical mean state is discussed in this paper.

scholarly journals Two-year consecutive concurrences of positive Indian Ocean Dipole and Central Pacific El Niño preconditioned the 2019/2020 Australian “black summer” bushfires

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Guojian Wang ◽  
Wenju Cai
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Greenhouse Warming ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Positive Indian Ocean Dipole ◽  
The Future ◽  
Rainfall Anomalies

Abstract The 2019/20 Australian black summer bushfires were particularly severe in many respects, including its early commencement, large spatial coverage, and large number of burning days, preceded by record dry and hot anomalies. Determining whether greenhouse warming has played a role is an important issue. Here, we examine known modes of tropical climate variability that contribute to droughts in Australia to provide a gauge. We find that a two-year consecutive concurrence of the 2018 and 2019 positive Indian Ocean Dipole and the 2018 and 2019 Central Pacific El Niño, with the former affecting Southeast Australia, and the latter influencing eastern and northeastern Australia, may explain many characteristics of the fires. Such consecutive events occurred only once in the observations since 1911. Using two generations of state-of-the-art climate models under historical and a business-as-usual emission scenario, we show that the frequency of such consecutive concurrences increases slightly, but rainfall anomalies during such events are stronger in the future climate, and there are drying trends across Australia. The impact of the stronger rainfall anomalies during such events under drying trends is likely to be exacerbated by greenhouse warming-induced rise in temperatures, making such events in the future even more extreme.

EL NINO EFFECTS ON THE ARCTIC STRATOSPHERE ACCORDING TO CMIP5 MODELS AND REANALYSIS

2021 ◽  
pp. 5-23
Author(s):  
M. A. Kolennikova ◽  
◽  
P. N. Vargin ◽  
D. Yu. Gushchina ◽  
◽  
...  
Keyword(s):  
El Niño ◽  
Climate Models ◽  
El Nino ◽  
Reanalysis Data ◽  
The Arctic ◽  
Cmip5 Models ◽  
Composite Analysis ◽  
Central Pacific ◽  
Coupled Climate Models

The response of the Arctic stratosphere to El Nio is studied with account of its Eastern and Central Pacific types for the period of 1950-2005. The study is based on the regression and composite analysis using the simulations with six CMIP5 coupled climate models and reanalysis data.

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