scholarly journals Active Role of the ITCZ and WES Feedback in Hampering the Growth of the Expected Full-Fledged El Niño in 2014

SOLA ◽  
2016 ◽  
Vol 12 (0) ◽  
pp. 17-21 ◽  
Author(s):  
Shuhei Maeda ◽  
Yusuke Urabe ◽  
Kazuto Takemura ◽  
Tamaki Yasuda ◽  
Youichi Tanimoto
Keyword(s):  
El Niño ◽  
El Nino ◽  
2012 ◽  
Vol 25 (9) ◽  
pp. 3321-3335 ◽  
Author(s):  
Masamichi Ohba ◽  
Masahiro Watanabe

Warm and cold phases of El Niño–Southern Oscillation (ENSO) exhibit a significant asymmetry in their transition/duration such that El Niño tends to shift rapidly to La Niña after the mature phase, whereas La Niña tends to persist for up to 2 yr. The possible role of sea surface temperature (SST) anomalies in the Indian Ocean (IO) in this ENSO asymmetry is investigated using a coupled general circulation model (CGCM). Decoupled-IO experiments are conducted to assess asymmetric IO feedbacks to the ongoing ENSO evolution in the Pacific. Identical-twin forecast experiments show that a coupling of the IO extends the skillful prediction of the ENSO warm phase by about one year, which was about 8 months in the absence of the IO coupling, in which a significant drop of the prediction skill around the boreal spring (known as the spring prediction barrier) is found. The effect of IO coupling on the predictability of the Pacific SST is significantly weaker in the decay phase of La Niña. Warm IO SST anomalies associated with El Niño enhance surface easterlies over the equatorial western Pacific and hence facilitate the El Niño decay. However, this mechanism cannot be applied to cold IO SST anomalies during La Niña. The result of these CGCM experiments estimates that approximately one-half of the ENSO asymmetry arises from the phase-dependent nature of the Indo-Pacific interbasin coupling.


2021 ◽  
pp. 1-38
Author(s):  
Tao Lian ◽  
Dake Chen

AbstractWhile both intrinsic low-frequency atmosphere–ocean interaction and multiplicative burst-like event affect the development of the El Niño–Southern Oscillation (ENSO), the strong nonlinearity in ENSO dynamics has prevented us from separating their relative contributions. Here we propose an online filtering scheme to estimate the role of the westerly wind bursts (WWBs), a type of aperiodic burst-like atmospheric perturbation over the western-central tropical Pacific, in the genesis of the centennial extreme 1997/98 El Niño using the CESM coupled model. This scheme highlights the deterministic part of ENSO dynamics during model integration, and clearly demonstrates that the strong and long-lasting WWB in March 1997 was essential for generating the 1997/98 El Niño. Without this WWB, the intrinsic low-frequency coupling would have only produced a weak warm event in late 1997 similar to the 2014/15 El Niño.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Abhik ◽  
Pandora Hope ◽  
Harry H. Hendon ◽  
Lindsay B. Hutley ◽  
Stephanie Johnson ◽  
...  

AbstractThis study investigates the underlying climate processes behind the largest recorded mangrove dieback event along the Gulf of Carpentaria coast in northern Australia in late 2015. Using satellite-derived fractional canopy cover (FCC), variation of the mangrove canopies during recent decades are studied, including a severe dieback during 2015–2016. The relationship between mangrove FCC and climate conditions is examined with a focus on the possible role of the 2015–2016 El Niño in altering favorable conditions sustaining the mangroves. The mangrove FCC is shown to be coherent with the low-frequency component of sea level height (SLH) variation related to the El Niño Southern Oscillation (ENSO) cycle in the equatorial Pacific. The SLH drop associated with the 2015–2016 El Niño is identified to be the crucial factor leading to the dieback event. A stronger SLH drop occurred during austral autumn and winter, when the SLH anomalies were about 12% stronger than the previous very strong El Niño events. The persistent SLH drop occurred in the dry season of the year when SLH was seasonally at its lowest, so potentially exposed the mangroves to unprecedented hostile conditions. The influence of other key climate factors is also discussed, and a multiple linear regression model is developed to understand the combined role of the important climate variables on the mangrove FCC variation.


2020 ◽  
Vol 20 (21) ◽  
pp. 13011-13022
Author(s):  
Yuanhong Zhao ◽  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Xin Lin ◽  
Antoine Berchet ◽  
...  

Abstract. Decadal trends and interannual variations in the hydroxyl radical (OH), while poorly constrained at present, are critical for understanding the observed evolution of atmospheric methane (CH4). Through analyzing the OH fields simulated by the model ensemble of the Chemistry–Climate Model Initiative (CCMI), we find (1) the negative OH anomalies during the El Niño years mainly corresponding to the enhanced carbon monoxide (CO) emissions from biomass burning and (2) a positive OH trend during 1980–2010 dominated by the elevated primary production and the reduced loss of OH due to decreasing CO after 2000. Both two-box model inversions and variational 4D inversions suggest that ignoring the negative anomaly of OH during the El Niño years leads to a large overestimation of the increase in global CH4 emissions by up to 10 ± 3 Tg yr−1 to match the observed CH4 increase over these years. Not accounting for the increasing OH trends given by the CCMI models leads to an underestimation of the CH4 emission increase by 23 ± 9 Tg yr−1 from 1986 to 2010. The variational-inversion-estimated CH4 emissions show that the tropical regions contribute most to the uncertainties related to OH. This study highlights the significant impact of climate and chemical feedbacks related to OH on the top-down estimates of the global CH4 budget.


Author(s):  
Martha Elizabeth Rayas Tanaka

Previous studies (Waxman, Senghas and Benveniste, 1997 and Waxman and Guasti 2009) have concluded that there are crosslinguistic differences in the interpretation of adjectives by English, French, Spanish and Italian- monolingual speaking children. Their results show that only Spanish and Italian-speaking children categorized a novel adjective as an object responding in the same way for the categorization of a noun. According to the authors this is due to the Determiner-Adjective syntactic constructions in these languages that refer to the named objects or entities and to other members of that object category (e.g. los pobres). The present study looks more precisely at the interpretation of adjectives by presenting a task in which children had to recognize adjectives as properties of objects and it explores the role of syntax and morphology as informative linguistic sources for their acquisition by using four different linguistic contexts. The results show that English- and Spanish- monolingual speaking children do understand that adjectives refer to properties and not to objects responding in a different way for a categorization of an adjective. Estudios anteriores (Waxman, Senghas and Benveniste, 1997 and Waxman and Guasti 2009) han concluido que existen diferencias croslingüísticas en la interpretación de los adjetivos por parte de los niños monolingües que hablan inglés, francés, español e italiano. Sus resultados muestran que solamente los niños que hablan español e italiano categorizan un adjetivo nuevo como un objeto respondiendo igual que a la categorización de un sustantivo. Los autores explican que esto se debe a las construcciones sintácticas de Articulo-Adjetivo en las lenguas mencionadas que se refieren a los objetos o entidades nombrados y a otros miembros de la categoría del objeto, por ejemplo: los pobres. El presente estudio analiza más precisamente la interpretación de los adjetivos presentando una tarea en el que el niño tiene que reconocer a los adjetivos como propiedades de objetos y explora el papel de la sintaxis y la morfología como recursos informativos lingüísticos para la adquisición de los adjetivos utilizando cuatro diferentes contextos lingüísticos. Los resultados muestran que los niños hablantes monolingües de inglés y español entienden que los adjetivos se refieren a las propiedades y no a los objetos respondiendo en forma diferente sobre la categorización de un adjetivo.


2018 ◽  
Vol 373 (1760) ◽  
pp. 20170407 ◽  
Author(s):  
Paul I. Palmer

The 2015/2016 El Niño was the first major climate variation when there were a range of satellite observations that simultaneously observed land, ocean and atmospheric properties associated with the carbon cycle. These data are beginning to provide new insights into the varied responses of land ecosystems to El Niño, but we are far from fully exploiting the information embodied by these data. Here, we briefly review the atmospheric and terrestrial satellite data that are available to study the carbon cycle. We also outline recommendations for future research, particularly the closer integration of satellite data with forest biometric datasets that provide detailed information about carbon dynamics on a range of timescales. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.


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