scholarly journals Impacts of canonical and Modoki El Niño on tropical Atlantic SST

2014 ◽  
Vol 119 (2) ◽  
pp. 777-789 ◽  
Author(s):  
Dillon J. Amaya ◽  
Gregory R. Foltz
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Atlantic

scholarly journals Spurious North Tropical Atlantic precursors to El Niño

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Zhang ◽  
Feng Jiang ◽  
Malte F. Stuecker ◽  
Fei-Fei Jin ◽  
Axel Timmermann
Keyword(s):  
El Niño ◽  
Cross Correlation ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Tropical Atlantic ◽  
The North ◽  
Sst Variability ◽  
Primary Driver ◽  
North Tropical Atlantic

AbstractThe El Niño-Southern Oscillation (ENSO), the primary driver of year-to-year global climate variability, is known to influence the North Tropical Atlantic (NTA) sea surface temperature (SST), especially during boreal spring season. Focusing on statistical lead-lag relationships, previous studies have proposed that interannual NTA SST variability can also feed back on ENSO in a predictable manner. However, these studies did not properly account for ENSO’s autocorrelation and the fact that the SST in the Atlantic and Pacific, as well as their interaction are seasonally modulated. This can lead to misinterpretations of causality and the spurious identification of Atlantic precursors for ENSO. Revisiting this issue under consideration of seasonality, time-varying ENSO frequency, and greenhouse warming, we demonstrate that the cross-correlation characteristics between NTA SST and ENSO, are consistent with a one-way Pacific to Atlantic forcing, even though the interpretation of lead-lag relationships may suggest otherwise.

scholarly journals Local Coupled Equatorial Variability versus Remote ENSO Forcing in an Intermediate Coupled Model of the Tropical Atlantic

2006 ◽  
Vol 19 (20) ◽  
pp. 5227-5252 ◽  
Author(s):  
Serena Illig ◽  
Boris Dewitte
Keyword(s):  
Mixed Layer ◽  
El Niño ◽  
Time Scale ◽  
El Nino ◽  
Coupled Model ◽  
Tropical Atlantic ◽  
Equatorial Atlantic ◽  
Layer Model ◽  
Intermediate Coupled Model ◽  
Mixed Layer Model

Abstract The relative roles played by the remote El Niño–Southern Oscillation (ENSO) forcing and the local air–sea interactions in the tropical Atlantic are investigated using an intermediate coupled model (ICM) of the tropical Atlantic. The oceanic component of the ICM consists of a six-baroclinic mode ocean model and a simple mixed layer model that has been validated from observations. The atmospheric component is a global atmospheric general circulation model developed at the University of California, Los Angeles (UCLA). In a forced context, the ICM realistically simulates both the sea surface temperature anomaly (SSTA) variability in the equatorial band, and the relaxation of the Atlantic northeast trade winds and the intensification of the equatorial westerlies in boreal spring that usually follows an El Niño event. The results of coupled experiments with or without Pacific ENSO forcing and with or without explicit air–sea interactions in the equatorial Atlantic indicate that the background energy in the equatorial Atlantic is provided by ENSO. However, the time scale of the variability and the magnitude of some peculiar events cannot be explained solely by ENSO remote forcing. It is demonstrated that the peak of SSTA variability in the 1–3-yr band as observed in the equatorial Atlantic is due to the local air–sea interactions and is not a linear response to ENSO. Seasonal phase locking in boreal summer is also the result of the local coupling. The analysis of the intrinsic sustainable modes indicates that the Atlantic El Niño is qualitatively a noise-driven stable system. Such a system can produce coherent interdecadal variability that is not forced by the Pacific or extraequatorial variability. It is shown that when a simple slab mixed layer model is embedded into the system to simulate the northern tropical Atlantic (NTA) SST variability, the warming over NTA following El Niño events have characteristics (location and peak phase) that depend on air–sea interaction in the equatorial Atlantic. In the model, the interaction between the equatorial mode and NTA can produce a dipolelike structure of the SSTA variability that evolves at a decadal time scale. The results herein illustrate the complexity of the tropical Atlantic ocean–atmosphere system, whose predictability jointly depends on ENSO and the connections between the Atlantic modes of variability.

scholarly journals Application of remote sensing to the study of the pelagic spiny lobster larval transport in the Tropical Atlantic

2009 ◽  
Vol 57 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Camila Aguirre Góes Rudorff ◽  
João Antônio Lorenzzetti ◽  
Douglas F. M. Gherardi ◽  
Jorge Eduardo Lins-Oliveira
Keyword(s):  
Diffusion Model ◽  
Satellite Data ◽  
El Niño ◽  
El Nino ◽  
Spiny Lobster ◽  
Ocean Dynamics ◽  
Tropical Atlantic ◽  
Geostrophic Current ◽  
Advection Diffusion ◽  
Larval Dispersion

The connectivity of marine populations via larval dispersal is crucial for the maintenance of fisheries production and biodiversity. Because larval dispersion takes place on different spatial scales, global operational satellite data can be successfully used to investigate the connectivity of marine populations on different spatial and temporal scales. In fact, satellite data have long been used for the study of the large and mesoscale biological processes associated with ocean dynamics. This paper presents simulations of spiny lobster larvae transport in the Tropical Atlantic using the geostrophic currents, generated by altimetry that feeds an advection/diffusion model. Simulations were conducted over the Tropical Atlantic (20ºN to 15ºS), considering four larvae release areas: the Cape Verde Archipelago, the Ivory Coast, Ascension Island and Fernando de Noronha Archipelago. We used mean geostrophic current (MGC) calculated from 2001 to 2005 to represent the mean circulation of the Tropical Atlantic. We also ran the model for the El Niño geostrophic current regime (ENGC) using part of the MGC data, representing the El Niño 2002/2003 event. Results suggest that the intensification of the mesoscale ocean processes associated with El Niño events promotes the connectivity between populations, increasing the chances of a genetic flux among different stocks. We concluded that the altimetry geostrophic current data together with a relatively simple advection/diffusion model can provide useful information about the physical dynamics necessary to conduct studies on larval dispersion.

Interannual Variability of Tropical Atlantic-to-Pacific Moisture Transport Linked to ENSO, Atlantic Niño, and Freshwater Budget in the Northwestern Tropical Atlantic

2021 ◽  
pp. 1-61
Author(s):  
Jun-Chao Yang ◽  
Yu Zhang ◽  
Ingo Richter ◽  
Xiaopei Lin
Keyword(s):  
Interannual Variability ◽  
Central America ◽  
North American ◽  
El Niño ◽  
Moisture Transport ◽  
El Nino ◽  
Late Summer ◽  
Tropical Atlantic ◽  
Freshwater Budget ◽  
Sst Gradient

AbstractMoisture transport from the Atlantic to Pacific is important for basin-scale freshwater budget and the formation of meridional ocean circulation. Although the climatological tropical Atlantic-to-Pacific moisture transport (TAPMORT) has been well investigated, few studies have focused on its variability. Here we investigate the interannual variability of TAPMORT based on the atmospheric reanalysis data sets. The TAPMORT interannual variability is dominated by the variations of trans-basin winds across Central America, and peaks in late boreal summer and late boreal winter. 1) In late summer, a developing El Niño and a mature Atlantic Niña set up an interbasin sea-surface temperature (SST) gradient that strengthens the low-level jet across Central America and therefore TAPMORT (with weakened TAPMORT for opposite signed events). This process typically occurs from July to September, with a peak in August. 2) In late winter, the strengthened southern North American center of the Pacific-North American-like pattern intensifies the TAPMORT variations. Although atmospheric interannual variability dominates these variations, extreme El Niño events are also important for the teleconnections. This process shows a single peak in February, in contrast to the persistent peak in late summer. We further demonstrate that the persistent TAPMORT variability in late summer dominates the moisture divergence over the northwestern tropical Atlantic and modulates freshwater flux there. Thus, our study improves the understanding of how TAPMORT interannual variability and the related interbasin SST gradient regulate the northwestern tropical Atlantic freshwater budget and the related salinity variability.

scholarly journals Observation of ENSO linked changes in the tropical Atlantic cloud vertical distribution using 14 years of MODIS observations

2019 ◽  
Author(s):  
Nils Madenach ◽  
Cintia Carbajal Henken ◽  
René Preusker ◽  
Odran Sourdeval ◽  
Jürgen Fischer
Keyword(s):  
Vertical Distribution ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Phase 1 ◽  
Tropical Atlantic ◽  
Phase 2 ◽  
High Cloud ◽  
La Nina ◽  
Linear Decrease

Abstract. 14 years (September 2002 to September 2016) of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) monthly mean cloud data is analyzed to identify possible changes of the cloud vertical distribution over the Tropical Atlantic Ocean (TAO). For the analysis multiple linear regression techniques are used. Within the investigated period, no significant trend in the domain-averaged cloud vertical distribution was found. In terms of linear changes, two major phases (before and after November 2011) in the time-series of the TAO domain-average Cloud Top Height (CTH) and High Cloud Fraction (HCF) can be distinguished. While phase 1 is dominated by a significant linear increase, phase 2 is characterized by a strong, significant linear decrease. The observed trends were mainly caused by the El Niño Southern Oscillation (ENSO). The increase in CTH and HCF in phase 1, was attributed to the transition from El Niño (2002) to La Niña (2011) conditions. The strong decrease in phase 2, was caused by the opposite transition from a La Niña (2011) to a major El Niño event (2016). A comparison with the large scale vertical motion ω at 500 hPa obtained from ERA-Interim ECMWF Re-Analyses and the Nino3.4-Index indicates that the changes in HCF are induced by ENSO linked changes in the large scale vertical upward movements over regions with strong large scale ascent. A first comparison with the DARDAR data set, which combines CloudSat radar and CALIPSO lidar measurements, shows qualitatively good agreements for the interannual variability of the high cloud amount and its linear decrease in phase 2.

scholarly journals Analysis and quantification of ENSO-linked changes in the tropical Atlantic cloud vertical distribution using 14 years of MODIS observations

2019 ◽  
Vol 19 (21) ◽  
pp. 13535-13546
Author(s):  
Nils Madenach ◽  
Cintia Carbajal Henken ◽  
René Preusker ◽  
Odran Sourdeval ◽  
Jürgen Fischer
Keyword(s):  
Time Series ◽  
Vertical Distribution ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Cloud Amount ◽  
Cloud Fraction ◽  
Tropical Atlantic ◽  
High Cloud

Abstract. A total of 14 years (September 2002 to September 2016) of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) monthly mean cloud data are used to quantify possible changes in the cloud vertical distribution over the tropical Atlantic. For the analysis multiple linear regression techniques are used. For the investigated time period significant linear changes were found in the domain-averaged cloud-top height (CTH) (−178 m per decade), the high-cloud fraction (HCF) (−0.0006 per decade), and the low-cloud amount (0.001 per decade). The interannual variability of the time series (especially CTH and HCF) is highly influenced by the El Niño–Southern Oscillation (ENSO). Separating the time series into two phases, we quantified the linear change associated with the transition from more La Niña-like conditions to a phase with El Niño conditions (Phase 2) and vice versa (Phase 1). The transition from negative to positive ENSO conditions was related to a decrease in total cloud fraction (TCF) (−0.018 per decade; not significant) due to a reduction in the high-cloud amount (−0.024 per decade; significant). Observed anomalies in the mean CTH were found to be mainly caused by changes in HCF rather than by anomalies in the height of cloud tops themselves. Using the large-scale vertical motion ω at 500 hPa (from ERA-Interim ECMWF reanalysis data), the observed anomalies were linked to ENSO-induced changes in the atmospheric large-scale dynamics. The most significant and largest changes were found in regions with strong large-scale upward movements near the Equator. Despite the fact that with passive imagers such as MODIS it is not possible to vertically resolve clouds, this study shows the great potential for large-scale analysis of possible changes in the cloud vertical distribution due to the changing climate by using vertically resolved cloud cover and linking those changes to large-scale dynamics using other observations or model data.

scholarly journals On the Inconsistent Relationship between Pacific and Atlantic Niños*

2012 ◽  
Vol 25 (12) ◽  
pp. 4294-4303 ◽  
Author(s):  
Joke F. Lübbecke ◽  
Michael J. McPhaden
Keyword(s):  
Wind Stress ◽  
El Niño ◽  
El Nino ◽  
Boreal Summer ◽  
Western Boundary ◽  
Tropical Atlantic ◽  
Cold Tongue ◽  
Trade Winds ◽  
Boreal Spring ◽  
Northern Tropical Atlantic

Abstract The tropical Atlantic wind response to El Niño forcing is robust, with weakened northeast trade winds north of the equator and strengthened southeast trade winds along and south of the equator. However, the relationship between sea surface temperature (SST) anomalies in the eastern equatorial Pacific and Atlantic is inconsistent, with El Niño events followed sometimes by warm and other times by cold boreal summer anomalies in the Atlantic cold tongue region. Using observational data and a hindcast simulation of the Nucleus for European Modeling of the Ocean (NEMO) global model at 0.5° resolution (NEMO-ORCA05), this inconsistent SST relationship is shown to be at least partly attributable to a delayed negative feedback in the tropical Atlantic that is active in years with a warm or neutral response in the eastern equatorial Atlantic. In these years, the boreal spring warming in the northern tropical Atlantic that is a typical response to El Niño is pronounced, setting up a strong meridional SST gradient. This leads to a negative wind stress curl anomaly to the north of the equator that generates downwelling Rossby waves. When these waves reach the western boundary, they are reflected into downwelling equatorial Kelvin waves that reach the cold tongue region in late boreal summer to counteract the initial cooling that is due to the boreal winter wind stress response to El Niño. In contrast, this initial cooling persists or is amplified in years in which the boreal spring northern tropical Atlantic warming is weak or absent either because of a positive North Atlantic Oscillation (NAO) phase or an early termination of the Pacific El Niño event.

scholarly journals ASSESSING CARBON SEQUESTRADED IN BRAZILIAN NORTHEASTERN BIOMES UNDER ENSO EVENTS

Gaia Scientia ◽  
2019 ◽  
Vol 13 (4) ◽  
Author(s):  
Robson de Sousa Nascimento ◽  
José Ivaldo Barbosa de Brito ◽  
Valéria Peixoto Borges
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Net Primary Production ◽  
Amazon Rainforest ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Tropical Atlantic ◽  
Enso Events ◽  
Caatinga Biome

The goal of the present study it was to know the behavior of the Net Primary Production (NPP) in years that have occurred El Niño Southern Oscillation (ENSO) and during the temperature anomalies of the surface of the Sea (SST) in the Tropical Atlantic, that is Atlantic Dipole. The results showed that the Amazon Rainforest, Atlantic Forest, and the Cerrado were not enough affected by the occurrence of El Niño Southern Oscillation and Atlantic Dipole. However, the Caatinga biome has shown to be quite sensitive to these events and patterns, especially in years of occurrence of El Niño, which contributed to a reduction in NPP; while in years of El Niña and negative dipole, the NPP achieved the highest values. The amount of rainfall in the previous year to the El Niño Southern Oscillation episodes showed influence on the amount of carbon sequestered by biomes in the year of study.

scholarly journals On the influences of the El Niño, La niña and Atlantic Dipole Paterni on the Amazonian Rainfall during 1960-1998

2000 ◽  
Vol 30 (2) ◽  
pp. 305-318 ◽  
Author(s):  
Everaldo B de SOUZA ◽  
Mary T KAYANO ◽  
Julio TOTA ◽  
Luciano PEZZI ◽  
Gilberto FISCH ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Austral Summer ◽  
La Niña ◽  
Tropical Atlantic ◽  
La Nina ◽  
Precipitation Anomalies ◽  
Dipole Pattern ◽  
Sst Anomalies

The influence of the large-scale climatic variability dominant modes in the Pacific and in the Atlantic on Amazonian rainfall is investigated. The composite technique of the Amazon precipitation anomalies is used in this work. The basis years for these composites arc those in the period 1960-1998 with occurrences of extremes in the Southern Oscillation (El Niño or La Niña) and the north/south warm (or cold) sea surface temperature (SST) anomalies dipole pattern in the tropical Atlantic. Warm (cold) dipole means positive (negative) anomalies in the tropical North Atlantic and negative (positive) anomalies in the tropical South Atlantic. Austral summer and autumn composites for extremes in the Southern Oscillation (El Niño or La Niña) and independently for north/south dipole pattern (warm or cold) of the SST anomalies in the tropical Atlantic present values (magnitude and sign) consistent with those found in previous works on the relationship between Amazon rainfall variations and the SST anomalies in the tropical Pacific and Atlantic. However, austral summer and autumn composites for the years with simultaneous occurrences of El Niño and warm north/south dipole of the SST anomalies in the tropical Atlantic show negative precipitation anomalies extending eastward over the center-eastern Amazon. This result indicates the important role played by the tropical Atlantic in the Amazon anomalous rainfall distribution.

Sign in / Sign up

Export Citation Format

Share Document