scholarly journals Studies of El Niño and Interdecadal Variability in Tropical Sea Surface Temperatures Using a Nonnormal Filter

2006 ◽  
Vol 19 (22) ◽  
pp. 5796-5815 ◽  
Author(s):  
Cécile Penland ◽  
Ludmila Matrosova
Keyword(s):  
El Niño ◽  
El Nino ◽  
Equatorial Indian Ocean ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Tropical Atlantic ◽  
The North ◽  
Surface Temperatures ◽  
Parabolic Structure ◽  
Tropical Sea

Abstract A dynamically based filter is used to separate tropical sea surface temperatures (SSTs) into three components: the evolving El Niño signal, the global tropical trend, and the background. The components thus isolated are not independent. On the contrary, this procedure allows us to see the importance of the interdecadal signal to the predictability of El Niño. The data filtered in this way reveal El Niño signals in the equatorial Indian Ocean and in the north tropical Atlantic Ocean that are remarkably similar. A signature of El Niño in the south tropical Atlantic leads Niño-3.4 SST anomalies by about 9 months. The time series of a global tropical trend is found to have a very smooth parabolic structure. In unfiltered data, this trend conspires with El Niño to obscure a meridional tropical Atlantic dipole, which is significant in the filtered background SST data.

North Australian Sea Surface Temperatures and the El Niño–Southern Oscillation in the CMIP5 Models

2012 ◽  
Vol 25 (18) ◽  
pp. 6375-6382 ◽  
Author(s):  
Jennifer L. Catto ◽  
Neville Nicholls ◽  
Christian Jakob
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Sea Surface ◽  
Cmip5 Models ◽  
Sea Surface Temperatures ◽  
The North ◽  
La Nina ◽  
Surface Temperatures

Abstract Aspects of the climate of Australia are linked to interannual variability of the sea surface temperatures (SSTs) to the north of the country. SST anomalies in this region have been shown to exhibit strong, seasonally varying links to ENSO and tropical Pacific SSTs. Previously, the models participating in phase 3 of the Coupled Model Intercomparison Project (CMIP3) have been evaluated and found to vary in their abilities to represent both the seasonal cycle of correlations between the Niño-3.4 and north Australian SSTs and the evolution of SSTs during composite El Niño and La Niña events. In this study, the new suite of models participating in the CMIP5 is evaluated using the same method. In the multimodel mean, the representation of the links is slightly improved, but generally the models do not capture the strength of the negative correlations during the second half of the year. The models also still struggle to capture the SST evolution in the north Australian region during El Niño and La Niña events.

scholarly journals Low-Frequency Variability of the Indian Monsoon–ENSO Relationship and the Tropical Atlantic: The “Weakening” of the 1980s and 1990s

2007 ◽  
Vol 20 (16) ◽  
pp. 4255-4266 ◽  
Author(s):  
F. Kucharski ◽  
A. Bracco ◽  
J. H. Yoo ◽  
F. Molteni
Keyword(s):  
Twentieth Century ◽  
El Niño ◽  
Indian Monsoon ◽  
El Nino ◽  
Ocean Model ◽  
Sea Surface ◽  
Boreal Summer ◽  
Sea Surface Temperatures ◽  
Tropical Atlantic ◽  
Surface Temperatures

Abstract The Indian monsoon–El Niño–Southern Oscillation (ENSO) relationship, according to which a drier than normal monsoon season precedes peak El Niño conditions, weakened significantly during the last two decades of the twentieth century. In this work an ensemble of integrations of an atmospheric general circulation model (AGCM) coupled to an ocean model in the Indian Basin and forced with observed sea surface temperatures (SSTs) elsewhere is used to investigate the causes of such a weakening. The observed interdecadal variability of the ENSO–monsoon relationship during the period 1950–99 is realistically simulated by the model and a dominant portion of the variability is associated with changes in the tropical Atlantic SSTs in boreal summer. In correspondence to ENSO, the tropical Atlantic SSTs display negative anomalies south of the equator in the last quarter of the twentieth century and weakly positive anomalies in the previous period. Those anomalies in turn produce heating anomalies, which excite a Rossby wave response in the Indian Ocean in both the model and the reanalysis data, impacting the time-mean monsoon circulation. The proposed mechanism of remote response of the Indian rainfall to tropical Atlantic sea surface temperatures is further tested forcing the AGCM coupled to the ocean model in the Indian Basin with climatological SSTs in the Atlantic Ocean and observed anomalies elsewhere. In this second ensemble the ENSO–monsoon relationship is characterized by a stable and strong anticorrelation through the whole second half of the twentieth century.

The Influence of ENSO on the Generation of Decadal Variability in the North Pacific*

2007 ◽  
Vol 20 (4) ◽  
pp. 667-680 ◽  
Author(s):  
Soon-Il An ◽  
Jong-Seong Kug ◽  
Axel Timmermann ◽  
In-Sik Kang ◽  
Oliver Timm
Keyword(s):  
El Niño ◽  
North Pacific ◽  
Decadal Variability ◽  
El Nino ◽  
Sea Surface ◽  
Diagnostic Study ◽  
Sea Surface Temperatures ◽  
The North ◽  
Surface Temperatures ◽  
The North Pacific

Abstract This diagnostic study explores the generation of decadal variability in the North Pacific resulting from the asymmetry of the El Niño–Southern Oscillation phenomenon and the nonlinearity of the atmospheric tropical–extratropical teleconnection. Nonlinear regression analysis of the North Pacific sea surface temperatures and atmospheric fields with respect to the ENSO index reveals that the main teleconnection centers shift between El Niño and La Niña years. This asymmetry in the ENSO response, together with the skewed probabilistic distribution of ENSO itself, may contribute to the generation of the long-term decadal variability of sea surface temperatures in the extratropical North Pacific. It is argued that this hypothesis may explain the significant variance of the observed Pacific decadal oscillation in the extratropics.

tamh tm iedor sphere -1 el 9a8 ti 0vse , lyc li s m im a p te le models. Much more detailed than in the Australian region (Simpson and Downey 1975; run. Rather they are models than simp allysofomuuscehdm ro ourte in eelxypesn in si cvee th to e V ha osicbe ee anndfoH rc uendt 198 recasting El Nino behav­ tures for the p w er iitohd4o ). bsT1eh rv e BMRC climate model iour (e.g., sea surface temperatures in the east simulated by the model ha 9s49e -d 9 1 se , aasnud rf ac th eet em ra p in efraal ­ lfeoqrueactaosrti al r Pacific), they could, in theory, be used to ob been compared with the coupling o ai fnftahleloacnedantetmoptehrea tu artemoosvpehre re la nidn . th Tehseew te asse rv ru end ra fiinvfea ll t i ( m Fr eesd , er w ik istehne th teal. s1a9m9e5 ). seTahesm ur o fa dceelmmo od deellss , ( hPoowweevrere , tis less than perfect. Improved ocean ph m er p ic e ra ctoun re d s it io bnust . s T li h ghtly different starting atmos­ these coupled mode alls . . 1995) are being developed for ialg lu rseterm ate esnttw he it h ‘ noobisseer ’ veind iffe ed rtahier ence betw nfa m ll, o w de e l . neTeoenge th t e ed to av mru uns O era cghep se aarsto ne pro onfalthperebd le ic m ti own it ihstthheeduisfef ic oufltcy oupled models in all five runs as an ‘ens coupled models has in sitmhue la attim ng osrp ai hnefrailclA of u st p ra rleicainpp it raetc io ip n i tat sihoon, w em abtls le’. eoam st e The en o ve srkin ll sem o rt ihne bl sei ave rn Amuusl rag t a ra ti lnegsgoennte he ia. (Ni ra l sp su a c ti caelsssca in le ssiimmuploartt in an gtaftomrousspeh rs e , ridcesvpairtieab th il e it iyr Fur T th h e es resoau tm th o , stphheem ri odels are less successful. sea cshuo rf l a ls ce1t9e9m6p ) e . ra M tu ordeealneoxmpaelriiemsehnatvsewailtohngspheicsitfo ie ry djtohb er e o fo f re si m pr uolbaa ti bnlgyc th cemSoOdIel ( eFx ig pe urrieme3n .3 ts ) . do ThaegSoO od I an be predicted without the need

Droughts ◽  
2016 ◽  
pp. 77-77
Keyword(s):  
El Niño ◽  
Climate Model ◽  
El Nino ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Coupled Models ◽  
Coupled Mode ◽  
Australian Region ◽  
Surface Temperatures

Tropical temperature in the Maastrichtian Danish Basin: Data from coccolith Δ47 and δ18O

Geology ◽  
2019 ◽  
Vol 47 (11) ◽  
pp. 1074-1078 ◽  
Author(s):  
Mattia Tagliavento ◽  
Cédric M. John ◽  
Lars Stemmerik
Keyword(s):  
Sea Surface ◽  
Polar Regions ◽  
Sea Surface Temperatures ◽  
Ice Caps ◽  
Greenhouse Climate ◽  
The North ◽  
Surface Temperatures ◽  
Higher Temperature ◽  
Clumped Isotope ◽  
Tropical Sea

Abstract The Cretaceous Earth, with its greenhouse climate and absence of major ice caps in the polar regions, represents an extreme scenario for modeling future warming. Despite considerable efforts, we are just at the verge of fully understanding the conditions of a warm Earth, and better, more extensive proxy evidence is needed to solve existing discrepancies between the applied temperature proxies. In particular, the Maastrichtian temperature trends are controversial, since data indicate cooling in the South Atlantic and contemporary warming of the North Atlantic. The “heat piracy” hypothesis involves northward heat transport to midlatitudes via oceanic currents and is used to explain the contrasting polar cooling/warming patterns. Here, we present Δ47 and δ18O data from nine coccolith-enriched samples from a shallow core taken from the Danish Basin (Chalk Sea), representing a key location at the northern mid-latitudes. Based on Δ47 data of coccolith-enriched material, sea-surface temperatures for the late Campanian–Maastrichtian ranged from 24 °C to 30 °C, with an average of 25.9 °C ± 2 °C. This is 4–6 °C higher than estimates based on Δ47 of bulk samples and 8–10 °C higher than reported temperatures based on bulk δ18O data from the same core. However, these higher temperature estimates are lower, but overall in line with estimates of Late Cretaceous tropical sea-surface temperatures from TEX86 (tetraether index of 86 carbons), when considering latitudinal differences. The study highlights the potential of clumped isotope paleothermometry on coccoliths as a valid, reliable proxy with which to reconstruct sea-surface temperatures.

scholarly journals Evidence of local sea surface temperatures overriding the southeast Australian rainfall response to the 1997-1998 El Niño

2015 ◽  
Vol 42 (21) ◽  
pp. 9449-9456 ◽  
Author(s):  
Peter van Rensch ◽  
Ailie J. E. Gallant ◽  
Wenju Cai ◽  
Neville Nicholls
Keyword(s):  
El Niño ◽  
El Nino ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Australian Rainfall
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