scholarly journals The Varied Impacts of El Niño–Southern Oscillation on Pacific Island Climates

2014 ◽  
Vol 27 (11) ◽  
pp. 4015-4036 ◽  
Author(s):  
Bradley F. Murphy ◽  
Scott B. Power ◽  
Simon McGree
Keyword(s):  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Convergence Zone ◽  
Pacific Island ◽  
Pacific Island Countries ◽  
Convergence Zones ◽  
Sst Anomalies

Abstract El Niño–Southern Oscillation (ENSO) drives interannual climate variability in many tropical Pacific island countries, but different El Niño events might be expected to produce varying rainfall impacts. To investigate these possible variations, El Niño events were divided into three categories based on where the largest September–February sea surface temperature (SST) anomalies occur: warm pool El Niño (WPE), cold tongue El Niño (CTE), and mixed El Niño (ME), between the other two. Large-scale SST and wind patterns for each type of El Niño show distinct and significant differences, as well as shifts in rainfall patterns in the main convergence zones. As a result, November to April rainfall in many Pacific island countries is significantly different among the El Niño types. In western equatorial Pacific islands, CTE events are associated with drier than normal conditions whereas ME and WPE events are associated with significantly wetter than normal conditions. This is due to the South Pacific convergence zone and intertropical convergence zone moving equatorward and merging in CTE events. Rainfall in the convergence zones is enhanced during ME and WPE and the displacement is smaller. La Niña events also show robust impacts that most closely mirror those of ME events. In the northwest and southwest Pacific strong CTE events have much larger impacts on rainfall than ME and WPE, as SST anomalies and correspondingly large-scale surface wind and rainfall changes are largest in CTE. While variations in rainfall exist between different types of El Niño and the significant impacts on Pacific countries of each event are different, the two extreme CTE events have produced the most atypical impacts.

scholarly journals Large-Scale Mode Impacts on the Sea Level over the Red Sea and Gulf of Aden

2019 ◽  
Vol 11 (19) ◽  
pp. 2224 ◽  
Author(s):  
Kamal A. Alawad ◽  
Abdullah M. Al-Subhi ◽  
Mohammed A. Alsaafani ◽  
Turki M. Alraddadi ◽  
Monica Ionita ◽  
...  
Keyword(s):  
Sea Level ◽  
Red Sea ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Positive Phase ◽  
El Nino Southern Oscillation ◽  
Gulf Of Aden ◽  
The Impact

Falling between seasonal cycle variability and the impact of local drivers, the sea level in the Red Sea and Gulf of Aden has been given less consideration, especially with large-scale modes. With multiple decades of satellite altimetry observations combined with good spatial resolution, the time has come for diagnosis of the impact of large-scale modes on the sea level in those important semi-enclosed basins. While the annual cycle of sea level appeared as a dominant cycle using spectral analysis, the semi-annual one was also found, although much weaker. The first empirical orthogonal function mode explained, on average, about 65% of the total variance throughout the seasons, while their principal components clearly captured the strong La Niña event (1999–2001) in all seasons. The sea level showed a strong positive relation with positive phase El Niño Southern Oscillation in all seasons and a strong negative relation with East Atlantic/West Russia during winter and spring over the study period (1993–2017). We show that the unusually stronger easterly winds that are displaced north of the equator generate an upwelling area near the Sumatra coast and they drive both warm surface and deep-water masses toward the West Indian Ocean and Arabian Sea, rising sea level over the Red Sea and Gulf of Aden. This process could explain the increase of sea level in the basin during the positive phase of El Niño Southern Oscillation events.

scholarly journals Tropical Cyclone Climatology of the South Pacific Ocean and Its Relationship to El Niño–Southern Oscillation

2012 ◽  
Vol 25 (18) ◽  
pp. 6108-6122 ◽  
Author(s):  
Andrew J. Dowdy ◽  
Lixin Qi ◽  
David Jones ◽  
Hamish Ramsay ◽  
Robert Fawcett ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
El Niño ◽  
Large Scale ◽  
Critical Line ◽  
El Nino ◽  
Southern Oscillation ◽  
South Pacific ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The South

Abstract Climatological features of tropical cyclones in the South Pacific Ocean have been analyzed based on a new archive for the Southern Hemisphere. A vortex tracking and statistics package is used to examine features such as climatological maps of system intensity and the change in intensity with time, average tropical cyclone system movement, and system density. An examination is presented of the spatial variability of these features, as well as changes in relation to phase changes of the El Niño–Southern Oscillation phenomenon. A critical line is defined in this study based on maps of cyclone intensity to describe the statistical geographic boundary for cyclone intensification. During El Niño events, the critical line shifts equatorward, while during La Niña events the critical line is generally displaced poleward. Regional variability in tropical cyclone activity associated with El Niño–Southern Oscillation phases is examined in relation to the variability of large-scale atmospheric or oceanic variables associated with tropical cyclone activity. Maps of the difference fields between different phases of El Niño–Southern Oscillation are examined for sea surface temperature, vertical wind shear, lower-tropospheric vorticity, and midtropospheric relative humidity. Results are also examined in relation to the South Pacific convergence zone. The common region where each of the large-scale variables showed favorable conditions for cyclogenesis coincided with the location of maximum observed cyclogenesis for El Niño events as well as for La Niña years.

scholarly journals Effects of large scale dynamic phenomena of the summer atmospheric circulation over the Aegean basin

2020 ◽  
Author(s):  
Ιωάννης Λογοθέτης
Keyword(s):  
Atmospheric Circulation ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Representative Concentration Pathways ◽  
Historical Scenario ◽  
Dynamic Phenomena

Η παρούσα διδακτορική διατριβή στοχεύει στη μελέτη των επιδράσεων δυναμικών φαινομένων μεγάλης κλίμακας στην ατμοσφαιρική κυκλοφορία της ανατολικής Μεσογείου εστιάζοντας στη λεκάνη του Αιγαίου κατά τη θερινή περίοδο (Μάιος - Σεπτέμβριος). Στο πλαίσιο της παρούσας έρευνας γίνεται μελέτη φαινομένων τηλεσύνδεσης που επιδρούν στην ατμοσφαιρική κυκλοφορία της ανατολικής Μεσογείου. Η ανάλυση γίνεται με δεδομένα από προσομοιώσεις Μοντέλων Γήινου Συστήματος (ESMs) που είναι διαθέσιμα στο πλαίσιο της πέμπτης φάσης του προγράμματος Σύγκρισης Συζευγμένων Μοντέλων (CMIP5), το οποίο δρα υποστηρικτικά για το Πόρισμα της Διακυβερνητικής Επιτροπής για τις Κλιματικές Αλλαγές (IPCC, AR5). Στο πλαίσιο του Πορίσματος του IPCC έχει αναπτυχθεί σειρά σεναρίων τα οποία χρησιμοποιούνται για την μελέτη του κλίματος. Η μελέτη εστιάζεται: (α) στην ιστορική περίοδο (historical scenario simulatiuons) για το παρόν-παρελθόν (1900-2005) και (β) προσομοιώσεις των Αντιπροσωπευτικών Συγκεντρώσεων (Representative Concentration Pathways, RCPc) για το μέλλον (2006-2100). Επίσης γίνεται χρήση δεδομένων επανανάλυσης (reanlysis data) από το Ευρωπαϊκό Κέντρο Μεσοπρόθεσμων Μετεωρολογικών Προγνώσεων (ECMWF) για το παρόν (ERA-Interim) και το παρελθόν (ERA20C), καθώς και δεδομένων παρατηρήσεων (observations) ανάλογα με τη διαθεσιμότητα. Στόχοι της διατριβής είναι η συμβολή στην κατανόηση της ατμοσφαιρικής κυκλοφορίας στην ανατολική Μεσόγειο, του φαινομένου των Ετησιών ανέμων και της τηλεσύνδεσης της Νότιας Κύμανσης (El- Niño Southern Oscillation; ENSO) με τον Ινδικό καλοκαιρινό Μουσώνα και την κυκλοφορία της ανατολικής Μεσογείου. Τα αποτελέσματα της διδακτορικής διατριβής έδειξαν ότι οι Ετησίες στην κατώτερη και η καθοδική κυκλοφορία στην μέση τροπόσφαιρα είναι τα κύρια χαρακτηριστικά της θερινής ατμοσφαιρικής κυκλοφορία στην ανατολική Μεσόγειο. Στην περιοχή του Ινδικού μουσώνα το κύριο χαρακτηριστικό της κυκλοφορίας είναι οι ανοδικές κινήσεις με την μέγιστη ένταση να εντοπίζεται στο τμήμα του δυτικού Ινδικού καλοκαιρινού Μουσώνα και στον κόλπο της Βεγγάλης. Οι ανοδικές κινήσεις πάνω από τον Ινδικό Μουσώνα, η καθοδική κυκλοφορία στην ανατολική Μεσόγειο και οι Ετησίες άνεμοι παρουσιάζουν ταυτόχρονα μέγιστο την περίοδο Ιουλίου-Αυγούστου. Στην περιοχή της ανατολικής Μεσογείου η βαθμίδα της πίεσης που δημιουργείται από την διαφορά των πιέσεων μεταξύ ενός κέντρου υψηλών πιέσεων στα βόρεια Βαλκάνια και ενός χαμηλού στην νοτιοανατολική Μεσόγειο είναι υπεύθυνη για την πνοή του συστήματος των Ετησιών ανέμων κατά την θερινή περίοδο στο Αιγαίο. Η ανάλυση έδειξε ότι τα μοντέλα είναι ικανά να προσομοιώσουν την εποχική εξέλιξη και συχνότητα των Ετησιών αν και υποεκτιμούν την ταχύτητα του ανέμου. Επιπλέον, η μελέτη επιβεβαιώνει την επίδραση του Ινδικού Μουσώνα στην κατώτερη, μέση και ανώτερη τροποσφαιρική κυκλοφορία της ανατολικής Μεσογείου. Επιπρόσθετα, η ανάλυση έδειξε την επίδραση του ENSO στον Ινδικό καλοκαιρινό Μουσώνα και στο κέντρο χαμηλών πιέσεων που εντοπίζεται στην νότιοανατολική Μεσόγειο ως τμήμα της επέκτασης ενός θερμικού χαμηλού που εκτείνεται από τον δυτικό Ινδικό μουσώνα μέχρι την νοτιοανατολική Μεσόγειο κατά τους καλοκαιρινούς μήνες. Οι εκτιμήσεις για την τελευταία περίοδο του εικοστού πρώτου αιώνα (2070-2100), με βάση το ακραίο σενάριο (RCP8.5), έδειξαν εξασθένηση της κυκλοφορίας μεγάλης κλίμακας και ενίσχυση της βροχόπτωσης στην περιοχή του Ινδικού Μουσώνα. Όπως στο παρελθόν έτσι και στο μέλλον η βαθμίδα της πίεσης στο Αιγαίο φαίνεται πως οδηγεί στην πνοή των Ετησιών ανέμων. Τέλος, η ανάλυση δεν έδειξε ξεκάθαρες μεταβολές για το σύστημα των Ετησιών.

scholarly journals The Impact of El Niño–Southern Oscillation (ENSO) on Temperature: A Case Study in Kuching, Sarawak

2021 ◽  
Vol 6 (1) ◽  
pp. 289-297
Author(s):  
Ricky Anak Kemarau ◽  
Oliver Valentine Eboy
Keyword(s):  
El Niño ◽  
Urban Areas ◽  
Large Scale ◽  
Building Materials ◽  
El Nino ◽  
Southern Oscillation ◽  
Meteorological Data ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The Impact

The El Niño–Southern Oscillation (ENSO) event is a climate event that has an impact on the world climate. The effects of ENSO are often associated with prolonged droughts and floods since 1980 following global climate change. In addition to causing flooding and drought. Indirectly, the occurrence of ENSO causes health problems, environmental destruction, affecting economic activities such as agriculture and fisheries. Many studies on ENSO have been conducted. However, there is still a lack of research on the effect of ENSO on temperature in local knowledge areas, especially urban areas because the urban environment especially building materials that can absorb and release heat. In addition, previous studies have focused on large-scale areas. Beside that there still gap to understand and increase knowledge about the effect of ENSO on local temperatures, especially in urban areas. This study uses meteorological data and Oceanic Nino Index (ONI) from 1988 to 2019. This study found that the occurrence of ENSO has an effect on the value of daily temperature but differs based on the value of the ONI index. In addition, this study uses linear regression in predicting the effect of ENSO on temperature. The results of this study are useful to those responsible for understanding the impact of ENSO on temperature in urban areas to provide infrastructure in reducing the impact of ENSO as well as adjustment measures during the occurrence of ENSO.

scholarly journals Differences in Atmospheric Circulation between the Development of Weak and Strong Warm Events in the Southern Oscillation

2007 ◽  
Vol 20 (10) ◽  
pp. 2191-2209 ◽  
Author(s):  
David J. Stephens ◽  
Michael J. Meuleners ◽  
Harry van Loon ◽  
Malcolm H. Lamond ◽  
Nicola P. Telcik
Keyword(s):  
High Pressure ◽  
El Niño ◽  
Large Scale ◽  
Rossby Waves ◽  
El Nino ◽  
Southern Oscillation ◽  
Surface Wind ◽  
South Pacific ◽  
The Pacific ◽  
Sst Anomalies

Abstract In this study temporal and spatial aspects of El Niño (warm event) development are explored by comparing composite sequences of sea level pressure (SLP), surface wind, and sea surface temperature (SST) anomalies leading into strong and weak events. El Niño strength is found to be related to the magnitude and spatial extent of large-scale SLP anomalies that move in a low-frequency mode. In association with this, it is also intricately linked to the amplitude and wavelength of the Rossby waves in the southern midlatitudes. The primary signature of the Southern Oscillation is a more pronounced standing wave of pressure anomalies between southeastern Australia and the central South Pacific leading into stronger events. A strong reversal in the strength of the annual cycle between these two regions causes a stronger (weaker) SLP gradient that drives southwesterly (northwesterly) wind stress forcing toward (away from) the western equatorial Pacific in austral winter–spring of year 0 (−1). Thus, pressure variations in the southwest Pacific preconditions the equatorial environment to a particular phase of ENSO and establishes the setting for greater tropical–extratropical interactions to occur in stronger events. Maximum warming in the Niño-3 region occurs between April and July (0) when a strong South Pacific trough most influences the trade winds at both ends of the Pacific. Cool SST anomalies that form to the east of high pressure anomalies over Indo–Australia assist an eastward propogation of high pressure into the Pacific midlatitudes and the demise of El Niño. Strong events have a more pronounced eastward propogation of SST and SLP anomalies and a much more noticeable enhancement of winter hemisphere Rossby waves from May–July (−1) to November–January (+1). Weak events require an enhanced South Pacific trough to develop but have much less support from the North Pacific. They also appear more variable in their development and more difficult to predict with lead time.

scholarly journals Differential Responses of Emergent Intertidal Coral Reef Fauna to a Large-Scale El-Niño Southern Oscillation Event: Sponge and Coral Resilience

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e93209 ◽  
Author(s):  
Francisco Kelmo ◽  
James J. Bell ◽  
Simone Souza Moraes ◽  
Rilza da Costa Tourinho Gomes ◽  
Eduardo Mariano-Neto ◽  
...  
Keyword(s):  
Coral Reef ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Differential Responses ◽  
Reef Fauna

scholarly journals Volcanic Eruptions, Large-Scale Modes in the Northern Hemisphere, and the El Niño–Southern Oscillation

2008 ◽  
Vol 21 (5) ◽  
pp. 910-922 ◽  
Author(s):  
Bo Christiansen
Keyword(s):  
Northern Hemisphere ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Volcanic Eruptions ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The Pacific ◽  
The Impact

Abstract The author analyzes the impact of 13 major stratospheric aerosol producing volcanic eruptions since 1870 on the large-scale variability modes of sea level pressure in the Northern Hemisphere winter. The paper focuses on the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) to address the question about the physical nature of these modes. The hypothesis that the phase of the El Niño–Southern Oscillation (ENSO) may control the geographical extent of the dominant mode in the Northern Hemisphere is also investigated, as well as the related possibility that the impact of the eruptions may be different according to the phase of ENSO. The author finds that both the AO and the NAO are excited in the first winter after the eruptions with statistical significance at the 95% level. Both the signal and the significance are larger for the NAO than for the AO. The excitation of the AO and the NAO is connected with the excitation of a secondary mode, which resembles an augmented Pacific–North American pattern. This mode has opposite polarity in the Atlantic and the Pacific and interferes negatively with the AO in the Pacific and positively in the Atlantic in the first winter after the eruptions, giving the superposition a strong NAO resemblance. Some evidence is found that the correlations between the Atlantic and the Pacific are stronger in the negative ENSO phase than in the positive phase, although this difference is not statistically significant when all data since 1870 are considered. The author does not find any evidence that the impact of the volcanic eruptions is more hemispheric in the negative than in the positive ENSO phase.

scholarly journals Modulation of the Northern Winter Stratospheric El Niño–Southern Oscillation Teleconnection by the PDO

2019 ◽  
Vol 32 (18) ◽  
pp. 5761-5783 ◽  
Author(s):  
Jian Rao ◽  
Chaim I. Garfinkel ◽  
Rongcai Ren
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
El Nino Southern Oscillation ◽  
Atmospheric Response ◽  
La Nina ◽  
The Pacific ◽  
Sst Anomalies

Using the CMIP5 multimodel ensemble (MME) historical experiments, the modulation of the stratospheric El Niño–Southern Oscillation (ENSO) teleconnection by the Pacific decadal oscillation (PDO) is investigated in this study. El Niño (La Niña) significantly impacts the extratropical stratosphere mainly during the positive (negative) PDO in the MME. Although the composite tropical ENSO SST intensities are similar during the positive and negative PDO in models, the Pacific–North American (PNA) responses are only significant when the PDO and ENSO are in phase. The local SST anomalies in the North Pacific can constructively (destructively) interfere with the tropical ENSO forcing to influence the extratropical eddy height anomalies when the PDO and ENSO are in (out of) phase. The difference between the positive and negative PDO in El Niño or La Niña winters filters out the tropical SST forcing, permitting the deduction of the extratropical SST contribution to the atmospheric response. The composite shows that the cold (warm) SST anomalies in the central North Pacific associated with the positive (negative) PDO have a similar impact to that of the warm (cold) SST anomalies in the tropical Pacific, exhibiting a positive (negative) PNA-like response, enhancing (weakening) the upward propagation of waves over the western coast of North America. The composite difference between the positive and negative PDO in El Niño or La Niña winters, as well as in eastern Pacific ENSO or central Pacific ENSO winters, presents a highly consistent atmospheric response pattern, which may imply a linear interference of the PDO’s impact with ENSO’s.

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