scholarly journals Intraseasonal Tropical Atmospheric Variability Associated with the Two Flavors of El Niño

2012 ◽  
Vol 140 (11) ◽  
pp. 3669-3681 ◽  
Author(s):  
Daria Gushchina ◽  
Boris Dewitte
Keyword(s):  
El Niño ◽  
El Nino ◽  
Wave Activity ◽  
Kelvin Wave ◽  
Atmospheric Variability ◽  
Central Pacific ◽  
Cp El Niño ◽  
Ocean Data Assimilation ◽  
Double Space ◽  
Ep El Niño

ABSTRACT The characteristics of intraseasonal tropical variability (ITV) associated with the two flavors of El Niño [i.e., the canonical or eastern Pacific (EP) El Niño and the Modoki or central Pacific (CP) El Niño] are documented using composite and regression analysis. Double space–time Fourier analysis is applied to the NCEP–NCAR zonal wind at 850 hPa (U850) to separate the different components of the ITV in the tropical troposphere, which is then used to define indices of wave activity, and document the spatial pattern of the waves. It is shown that the ITV characteristics are altered during CP El Niño compared to the typical seasonal dependence of the ITV–ENSO relationship. In particular, while EP El Niño is characterized by enhanced MJO and equatorial Rossby (ER) wave activity during spring–summer prior to the ENSO peak, during CP El Niño, the ITV activity is increased during the mature and decaying phases. It is suggested that ITV is more propitious to the triggering of the EP event; while during the CP event, it contributes mostly to the persistence of positive SST anomalies. The oceanic response of these ITV anomalous patterns is further investigated in the Simple Ocean Data Assimilation (SODA) reanalysis by documenting the seasonal evolution of the intraseasonal equatorial oceanic Kelvin wave (IEKW) activity during the two flavors of El Niño. It is shown that anomalous westerlies associated with ITV may generate the corresponding response in the ocean in the form of anomalous IEKW activity.

scholarly journals Evolution of the Madden–Julian Oscillation in Two Types of El Niño

2016 ◽  
Vol 29 (5) ◽  
pp. 1919-1934 ◽  
Author(s):  
Xiong Chen ◽  
Jian Ling ◽  
Chongyin Li
Keyword(s):  
El Niño ◽  
El Nino ◽  
Moisture Flux ◽  
Early Summer ◽  
Western Pacific ◽  
Madden Julian Oscillation ◽  
Central Pacific ◽  
Cp El Niño ◽  
Ep El Niño ◽  
The Western Pacific

Abstract Evolution characteristics of the Madden–Julian oscillation (MJO) during the eastern Pacific (EP) and central Pacific (CP) types of El Niño have been investigated. MJO activities are strengthened over the western Pacific during the predeveloping and developing phases of EP El Niño, but suppressed during the mature and decaying phases. In contrast, MJO activities do not show a clear relationship with CP El Niño before their occurrence over the western Pacific, but they increase over the central Pacific during the mature and decaying phases of CP El Niño. Lag correlation analyses further confirm that MJO activities over the western Pacific in boreal spring and early summer are closely related to EP El Niño up to 2–11 months later, but not for CP El Niño. EP El Niño tends to weaken the MJO and lead to a much shorter range of its eastward propagation. Anomalous descending motions over the Maritime Continent and western Pacific related to El Niño can suppress convection and moisture flux convergence there and weaken MJO activities over these regions during the mature phase of both types of El Niño. MJO activities over the western Pacific are much weaker in EP El Niño due to the stronger anomalous descending motions. Furthermore, the MJO propagates more continuously and farther eastward during CP El Niño because of robust moisture convergence over the central Pacific, which provides adequate moisture for the development of MJO convection.

scholarly journals Pengaruh Central Pacific dan eastern Pacific El Nino terhadap variabilitas curah hujan di Sulawesi

2018 ◽  
Vol 15 (2) ◽  
pp. 73
Author(s):  
Budi Prasetyo ◽  
Nikita Pusparini
Keyword(s):  
Data Assimilation ◽  
El Niño ◽  
El Nino ◽  
Climate Prediction ◽  
Eastern Pacific ◽  
Central Pacific ◽  
Eastern Pacific El Niño ◽  
Ocean Data Assimilation ◽  
Ep El Niño ◽  
Climate Prediction Center

Pulau Sulawesi dipengaruhi oleh fenomena Central Pacific (CP) dan Eastern Pacific (EP) El Niño. Curah hujan Sulawesi mencakup ketiga pola hujan yang ada di Indonesia yaitu Monsunal, equatorial, dan lokal. Variabilitas ketiga pola curah hujan tersebut akan memberikan respon yang berbeda terhadap pengaruh dari kedua tipe El Niño tersebut. Maka, Kajian ini akan membahas pengaruh dari kedua tipe El Niño  terhadap curah hujan Sulawesi. Penelitian ini Menggunakan data curah hujan bulanan berasal dari Climate Prediction Center (CPC) National Oceanic and Atmospheric Administration (NOAA), Suhu Permukaan Laut (SPL) bulanan dari System Ocean Data Assimilation (SODA) versi 2.2.4 dan oceanic Niño Indeks (ONI) dengan periode  Januari 1950 hingga Desember 2010 (60 tahun). Perhitungan statistik sederhana berupa perata-rataan, korelasi, dan analisa komposit digunakan dalam kajian ini. Penentuan tipe El Niño menggunakan tiga buah indeks yang berbeda. Hasilnya diperoleh bahwa Curah hujan Sulawesi berkurang saat kedua tipe El Niño. Penurunan curah hujan akibat EP El Niño berkisar antara 5 – 20 mm sedangkan akibat CP El Niño berkisar antara 2-12 mm. Wilayah Sulawesi dengan pola curah hujan monsunal merupakan wilayah yang mengalami penurunan curah hujan terbesar akibat kedua tipe El Niño tersebut, kemudian diikuti dengan pola curah hujan equatorial dan terakhir Lokal.

scholarly journals Profil Vertikal Suhu Laut Banda Terkait Kejadian El Niño di Pasifik Timur dan Pasifik Tengah

2019 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Budi Prasetyo ◽  
Nikita Pusparini ◽  
Ivonne Milichristi Radjawanne
Keyword(s):  
Surface Layer ◽  
El Niño ◽  
El Nino ◽  
Maximum Temperature ◽  
Temperature Decrease ◽  
Central Pacific ◽  
Sea Temperature ◽  
Near Surface ◽  
Cp El Niño ◽  
Ep El Niño

<strong>Vertical Profile of Banda Sea Temperature Related to El Niño Events in the East Pacific and Central Pacific</strong>.Eastern Pacific (EP) and Central Pacific El Niño have different characteristics such as mechanism, evolution, impact to Sea Surface Temperature (SST), and rainfall. The character of two types of El Nino affect the temperature of the sea, on the near-surface as well as in deeper layer, in other regions including Banda Sea. This study is aimed to understand the response of Banda Sea vertical sea temperature profile to both El Niño types using sea temperature data from Simple Ocean Data Assimilation (SODA) v.2.2.4 from January 1950 until December 2010 (60 years), Oceanic Nino Index (ONI), and mixed layer depth (MLD) from SODA3. Eastern Pacific El Niño and CP El Niño cooled Banda Sea about -1.5°C and 0.9°C, respectively. The maximum cooling due to both El Niño occurred in the thermocline layer (at the depth of 90 to 120m). The maximum temperature decrease during EP El Niño occurred at the depth of 90 to 120 m, while during CP El Niño the maximum temperature decrease was at 140 to 160 m and 160 to 200m in western and eastern Banda Sea, respectively. The temperature of the near-surface layer responded rapidly to CP El Niño while in the deep layer the temperature responded more to EP El Niño. The Banda deep sea layer was cooling after both types of El Niño extinct while the temperature of near-surface layer was increasing when CP El Niño extinct.

scholarly journals Interdecadal Relationship between the Mean State and El Niño Types*

2013 ◽  
Vol 26 (2) ◽  
pp. 361-379 ◽  
Author(s):  
Pei-Hsuan Chung ◽  
Tim Li
Keyword(s):  
El Niño ◽  
El Nino ◽  
Atmospheric Precipitation ◽  
Frequent Occurrence ◽  
Central Pacific ◽  
Cp El Niño ◽  
Budget Analysis ◽  
Ep El Niño ◽  
The Mean ◽  
Mean State

Abstract The interdecadal change of the mean state and two types of El Niño was investigated based on the analysis of observational data from 1980 to 2010. It was found that easterly trades and sea surface temperature (SST) gradients across the equatorial Pacific undergo a regime change in 1998/99, with enhanced trades and a significant cooling (warming) over tropical eastern (western) Pacific in the later period. Accompanying this mean state change is more frequent occurrence of central Pacific (CP) El Niño during 1999–2010. The diagnosis of air–sea feedback strength showed that atmospheric precipitation and wind responses to CP El Niño are greater than those to the eastern Pacific (EP) El Niño for given a unit SST anomaly (SSTA) forcing. The oceanic response to the same wind forcing, however, is greater in the EP El Niño than in the CP El Niño. A mixed layer heat budget analysis reveals that zonal advection (thermocline change induced vertical advection) primarily contributes to the CP (EP) El Niño growth. The role of the mean SST zonal gradient in El Niño selection was investigated through idealized numerical experiments. With the increase of the background zonal SST gradient, the anomalous wind and convection response to a specified EP or CP SSTA shift to the west. Such a difference results in a bifurcation of maximum SSTA tendency, as shown from a simple ocean model. The numerical results support the notion that a shift to the La Niño–like interdecadal mean state is responsible for more frequent occurrence of CP-type El Niño.

scholarly journals On the Relationship between the North Pacific Climate Variability and the Central Pacific El Niño

2015 ◽  
Vol 28 (2) ◽  
pp. 663-677 ◽  
Author(s):  
Sang-Wook Yeh ◽  
Xin Wang ◽  
Chunzai Wang ◽  
Boris Dewitte
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Atmospheric Variability ◽  
Central Pacific ◽  
Cp El Niño ◽  
The North ◽  
Pacific Climate Variability ◽  
The Relationship ◽  
The North Pacific

Abstract This study examined connections between the North Pacific climate variability and occurrence of the central Pacific (CP) El Niño for the period from 1950 to 2012. A composite analysis indicated that the relationship between the North Pacific sea surface temperature (SST), along with its overlying atmospheric circulation, and the CP El Niño during the developing and mature phases was changed when the occurrence frequency of the CP El Niño significantly increased after 1990. Empirical orthogonal function (EOF) and singular value decomposition (SVD) analyses of variability in the tropical Pacific and its relationship to the North Pacific show that the North Pacific anomalous SST and the atmospheric variability are more closely associated with the occurrence of the CP El Niño after 1990 than before 1990. There were noticeable differences in terms of the atmospheric variability conditions over the North Pacific, such as the North Pacific Oscillation (NPO)-like atmospheric variability during the spring and its associated SST anomalies during the following winter before 1990 and after 1990. In addition, combined EOF analysis also indicated that the NPO-like atmospheric circulation becomes more effective at playing a role in initiating El Niño after 1990. Consequently, such a change might have been associated with the frequent occurrence of the CP El Niño after 1990.

scholarly journals Global Monsoon Precipitation: Trends, Leading Modes, and Associated Drought and Heat Wave in the Northern Hemisphere

2018 ◽  
Vol 31 (17) ◽  
pp. 6947-6966 ◽  
Author(s):  
Kaiqiang Deng ◽  
Song Yang ◽  
Mingfang Ting ◽  
Yaheng Tan ◽  
Shan He
Keyword(s):  
Northern Hemisphere ◽  
El Niño ◽  
El Nino ◽  
Boreal Summer ◽  
Soil Conditions ◽  
Monsoon Precipitation ◽  
Central Pacific ◽  
Global Monsoon ◽  
Cp El Niño ◽  
Ep El Niño

Global monsoon precipitation (GMP) brings the majority of water for the local agriculture and ecosystem. The Northern Hemisphere (NH) GMP shows an upward trend over the past decades, while the trend in the Southern Hemisphere (SH) GMP is weak and insignificant. The first three singular value decomposition modes between NH GMP and global SST during boreal summer reflect, in order, the Atlantic multidecadal oscillation (AMO), eastern Pacific (EP) El Niño, and central Pacific (CP) El Niño, when the AMO dominates the NH climate and contributes to the increased trend. However, the first three modes between SH GMP and global SST during boreal winter are revealed as EP El Niño, the AMO, and CP El Niño, when the EP El Niño becomes the most significant driver of the SH GMP, and the AMO-induced rainfall anomalies may cancel out each other within the SH global monsoon domain and thus result in a weak trend. The intensification of NH GMP is proposed to favor the occurrences of droughts and heat waves (HWs) in the midlatitudes through a monsoon–desert-like mechanism. That is, the diabatic heating associated with the monsoonal rainfall may drive large-scale circulation anomalies and trigger intensified subsidence in remote regions. The anomalous descending motions over the midlatitudes are usually accompanied by clear skies, which result in less precipitation and more downward solar radiation, and thus drier and hotter soil conditions that favor the occurrences of droughts and HWs. In comparison, the SH GMP may exert much smaller impacts on the NH extremes in spring and summer, probably because the winter signals associated with SH GMP cannot sufficiently persist into the following seasons.

scholarly journals Different Evolutions of the Philippine Sea Anticyclone between the Eastern and Central Pacific El Niño: Possible Effects of Indian Ocean SST

2012 ◽  
Vol 25 (22) ◽  
pp. 7867-7883 ◽  
Author(s):  
Yuan Yuan ◽  
Song Yang ◽  
Zuqiang Zhang
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
The Philippines ◽  
Northern Indian Ocean ◽  
Central Pacific ◽  
Low Level ◽  
Cp El Niño ◽  
Anomalous Anticyclone ◽  
Ep El Niño

Abstract The authors examine different evolution features of the low-level anticyclone over the tropical northwestern Pacific between eastern Pacific (EP) El Niño events and central Pacific (CP) El Niño events. During EP El Niño, the low-level anticyclone shows an eastward movement from the northern Indian Ocean to the east of the Philippines. During CP El Niño, however, the anticyclone is mostly confined to the west of the Philippines. It is weaker, exhibits a shorter lifetime, and lacks eastward movement compared to the Philippine Sea anticyclone (PSAC) during EP El Niño. Investigation into the possible impact of Indian Ocean (IO) sea surface temperature (SST) on the evolution of the low-level anticyclone during EP and CP El Niño indicates that both SST and low-level atmospheric circulation over the IO are related more strongly with EP El Niño than with CP El Niño. The IO SST tends to exert a more prominent influence on PSAC during EP El Niño than during CP El Niño. During the developing summer and autumn of EP El Niño, the anomalous anticyclone over the northern Indian Ocean excited by positive IO dipole may contribute to an early development of the PSAC. During the winter and decaying spring, the anomalous anticyclone to the east of the Philippines instigated by the IO basin-wide warming mode also favors a larger persistence of the PSAC. During CP El Niño, however, IO SST shows a negligible impact on the evolution of the anticyclone.

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 Attenuation of Central Pacific El Niño Amplitude by North Pacific Sea Surface Temperature Anomalies

2020 ◽  
Vol 33 (15) ◽  
pp. 6673-6688 ◽  
Author(s):  
Kang Xu ◽  
Chi-Yung Tam ◽  
Boqi Liu ◽  
Sheng Chen ◽  
Xiaoyi Yang ◽  
...  
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Sea Surface ◽  
Central Pacific ◽  
Cp El Niño ◽  
The North ◽  
Sea Surface Temperature Anomalies ◽  
Ep El Niño ◽  
The North Pacific

AbstractThere exists a pronounced asymmetry between the amplitudes of central Pacific (CP) and eastern Pacific (EP) El Niño sea surface temperature anomalies (SSTA). The present study examines such an asymmetry and its relationship with the North Pacific SSTA. Results indicate that the weaker CP El Niño amplitude can be attributed to the weaker anomalous zonal wind response to the east–west equatorial SSTA gradient during its growing phase compared with EP El Niño. Furthermore, the occurrence of CP El Niño is closely associated with southwesterly surface wind anomalies in the subtropical North Pacific, as well as ocean warming reminiscent of the North Pacific Gyre Oscillation (NPGO) pattern in its vicinity. Both the observations as well as the pacemaker experiments with a coupled global climate model suggest that the anomalous low-level southwesterlies, induced by the North Pacific Oscillation (NPO)-like atmospheric variability, can enhance anomalously positive SST signals and extend them southwestward to the central equatorial Pacific via the wind–evaporation–SST feedback. This will further attenuate the atmospheric response to zonal SSTA gradient, and hence weaken the amplitude of CP El Niño. Therefore, anomalous low-level southwesterlies over the subtropical North Pacific can effectively act as a conduit for tropical–subtropical air–sea interaction in that region, and can play an important role in limiting the intensity of CP El Niño.

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.

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