scholarly journals Can small pelagic fish landings be used as predictors of high-frequency oceanographic fluctuations in the 1–2 El Niño region?

2016 ◽  
Vol 42 ◽  
pp. 61-72 ◽  
Author(s):  
Franklin Isaac Ormaza-González ◽  
Alejandra Mora-Cervetto ◽  
Raquel María Bermúdez-Martínez ◽  
Mario Armando Hurtado-Domínguez ◽  
Manuel Raúl Peralta-Bravo ◽  
...  
Keyword(s):  
Linear Correlation ◽  
El Niño ◽  
El Nino ◽  
Pelagic Fish ◽  
La Niña ◽  
Negative Slope ◽  
South American ◽  
Small Pelagic Fish ◽  
La Nina

Abstract. A group of small pelagic fish captured between 1981 and 2012 within El Niño area 1–2 by the Ecuadorian fleet was correlated with the oceanographic Multivariate ENSO Index (MEI), and the Oceanographic El Niño Index (ONI) referred to El Niño region 3–4. For the period 1981–2012, total landings correlated poorly with the indexes, but during 2000–2012 (cold PDO) they proved to have a 14–29 % association with both indexes; the negative slope of the curves suggested higher landing during cold events (La Niña) and also indicated a tendency to decrease at extreme values ( >  0.5 and  < −1.0). Round herring (Etrumeus teres) fourth-quarter (Q4) landings were related to the MEI in a nonlinear analysis by up to 80 %. During moderate or strong La Niña events landings noticeably increased. Bullet tuna (Auxis spp.) catches showed a negative gradient from cold to warm episodes with an R2 of 0.149. For Chilean jack mackerel (Trachurus murphyi) irregular landings between 2003 and 2007 were observed and were poorly correlated (R2 < 0.1) with ONI or MEI. Anchovy (Engraulis ringens) captured in Ecuadorian waters since 2000 had an R2 of 0.302 and 0.156 for MEI and ONI, respectively, but showed a higher correlation with the cold Pacific Decadal Oscillation (PDO). South American pilchard (Sardinops sagax) was higher than −0.5 for the ONI and MEI, and landings dramatically decreased; however, Q4 landings correlated with ONI and MEI, with R2 of 0.109 and 0.225, respectively (n = 3). Linear correlation of Q4 indexes against the following year's Q1 landings had a linkage of up to 22 %; this species could therefore be considered a predictor of El Niño. Chub mackerel (Scomber japonicus) landings did not have a significant linear correlation with the indexes for 1981–2012 and therefore could not be considered a valid predictor. Chuhueco (Cetengraulis mysticetus) is a local species with high landings during El Niño years and, conversely, remarkably low landings during La Niña years. Additionally, chuhueco availability and landings were negatively affected by cold PDOs. Pacific thread herring (Opisthonema spp.) showed a 24 and 36 % relationship between landings (Q1) and the MEI and ONI (Q4). Therefore, results suggest that the South American pilchard and Pacific thread herring could be considered good species to use as predictors of El Niño in region 1–2 (Ecuador), especially when average Q4 MEI ∕ ONI is used against the next trimester Q1 landing. All species were prone to lower landings and/or fishing availability during strong–extreme events (ONI/MEI,  >  1.0 and  <  −1.0), and were also shown to be affected by the PDO. In the long term, landings decreased under warm PDO and vice versa, and therefore PDO fluctuations could be used to help manage these fisheries and to help the industry in long-term planning.

Sub-monthly variability of the South American summer precipitation under El Niño and La Niña backgrounds during the 1998-2012 period

2018 ◽  
Vol 38 (5) ◽  
pp. 2153-2166 ◽  
Author(s):  
Alexandra Amaro de Lima ◽  
Rita Valéria Andreoli ◽  
Mary Toshie Kayano
Keyword(s):  
El Niño ◽  
El Nino ◽  
Summer Precipitation ◽  
La Niña ◽  
South American ◽  
The South ◽  
La Nina

scholarly journals An Investigation of the Southern Ocean Surface Temperature Variability Using Long-Term Optimum Interpolation SST Data

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Megha Maheshwari ◽  
Rajkumar Kamaljit Singh ◽  
Sandip Rashmikant Oza ◽  
Raj Kumar
Keyword(s):  
Southern Ocean ◽  
El Niño ◽  
El Nino ◽  
Linear Trend ◽  
Critical Role ◽  
La Niña ◽  
Optimum Interpolation ◽  
La Nina ◽  
Sst Anomaly

An attempt is made to understand the long-term variability of SST using NOAA optimum interpolation SST data for the period (1982–2011) in the Southern Ocean. This dataset has been used (i) to study the interannual variability in SST anomaly and (ii) to carry out regression analysis to compute linear trend in the annual averaged Southern Ocean SST. It is observed that summer season exhibits more variability than winter. Moreover, El Nino/La Nina events apparently play a critical role in the variability of Southern Ocean SST. Thus, higher SST anomalies were observed in El Nino years (e.g., 1983), while cooler anomalies were seen during La Nina years (e.g., 1985). In addition, the eastern and western sides of Antarctica experience episodes of warm and cold SST. Western parts of the Southern Ocean experienced higher anomalies during 1992, 1993, and 1994, while the eastern part experienced positive anomalies in 1997, 1998, 2002, and 2003. The paper also highlights the different regions of the Southern Ocean showing statistically significant positive/negative trends in the variability of interannual average SST. However, in general, the Southern Ocean as a whole is showing a weak interannual cooling trend in SST.

scholarly journals VARIATION IN THE SURFACE CURRENTS IN THE PANAMA BIGHT DURING EL NIÑO AND LA NIÑA EVENTS FROM 1993 TO 2007

2016 ◽  
Vol 40 ◽  
Author(s):  
Andrea Corredor Acosta ◽  
Alberto Acosta ◽  
Phillipe Gaspar ◽  
Beatriz Calmettes
Keyword(s):  
El Niño ◽  
El Nino ◽  
Anticyclonic Eddy ◽  
La Niña ◽  
Moderate Intensity ◽  
South American ◽  
Surface Currents ◽  
The South ◽  
La Nina ◽  
Oceanic Currents

Climatic anomalies have changed the ocean circulation pattern and thus the demographic connectivity. However, in many geographical regions there is insufficient evidence of this change. Therefore, comparisons were made between neutral years and years of El Niño and La Niña with moderate intensity, for the North Equatorial Counter Current (NECC), the South Equatorial Current (SEC), the Coastal Current (CoaC) and the main anticyclonic eddy in the Panama Bight. Daily dynamics topography data of the Maps of Absolute Dynamic Topography (MADT) provided by AVISO and daily wind stress data provide by the European Centre for Medium Range Weather (ECMWF) were used to calculate the speed of surface currents (multi-year, quarterly average), during months with the highest number of eggs and larvae released by the species with a pelagic phase (Sept-Nov). It was found that the speed magnitude for the three oceanic currents was statistically different among the compared events, except for the anticyclonic eddy; obtaining higher values of speed for neutral years in relation to years with El Niño or La Niña for the NECC, for the SEC higher values for La Niña years, followed by neutral years and a moderate El Niño years; for the CoaC higher velocity for neutral and La Niña years but the lowest for El Niño years; and a tendency of higher values in La Niña years for the anticyclonic eddy. Additionally, the number of eddies increased in moderate El Niño years. The results suggest that the decreased velocity of the NECC and the potential barriers created by the cyclonic eddies and the anticyclonic eddy near the South American coast could diminish the passive dispersal of larvae and the potential functional connectivity between the Western, Central and Eastern Tropical Pacific. Therefore, there are implications at the evolutionary, biogeographic, and ecologic levels (dispersion rates and population rescue effect). In contrast, during La Niña the SEC could favor teleplanktonic larval transport to the Central Pacific, material which is exported from the South American coast by CoaC, aided by the anticyclonic eddy. In conclusion, anomalous climatic events alter the velocity of oceanic currents in the Panama Bight; consequently these could change the functional potential connectivity from September to November.

scholarly journals Long-Term Variation in Survival of A Neotropical Freshwater Turtle: Habitat and Climatic Influences

Diversity ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 97 ◽  
Author(s):  
Mario F. Garcés-Restrepo ◽  
John L. Carr ◽  
Alan Giraldo
Keyword(s):  
El Niño ◽  
Transition Probabilities ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Freshwater Turtle ◽  
Freshwater Turtles ◽  
La Nina ◽  
Enso Phases

Few long-term demographic studies have been conducted on freshwater turtles of South America, despite the need for this type of inquiry to investigate natural variation and strengthen conservation efforts for these species. In this study, we examined the variation in demography of the Chocoan River Turtle (Rhinoclemmys nasuta) based on a population from an island locality in the Colombian Pacific region between 2005 and 2017. We calculated survival, recapture, and transition probabilities, and the effects of stream substrate and El Niño–Southern Oscillation (ENSO) phases (El Niño, Neutral, La Niña) on these variables using a multi-state model. We found differences in survival probabilities between ENSO phases, likely as a consequence of an increase in flood events. In addition, we found support for survival being greater in muddy streams than rocky streams, possibly because it is easier to escape or hide in mud substrates. Recapture probabilities varied by life stages; differences in the probability of recapture between size classes were associated with the high fidelity to territories by adults. The present increases in frequency and severity of El Niño and La Niña may exacerbate the consequences of climatic regimes on natural populations of turtles by increasing the mortality caused by drastic phenomena such as floods.

Decadal and Century-Long Changes in Storminess at Long-Term Ecological Research Sites

2003 ◽  
Author(s):  
Bruce P. Hayden ◽  
Nils R. Hayden
Keyword(s):  
United States ◽  
El Niño ◽  
El Nino ◽  
La Niña ◽  
Jet Stream ◽  
Ecological Research ◽  
La Nina ◽  
Extratropical Storms ◽  
Long Term Ecological Research

Ecological disturbances at Long-Term Ecological Research (LTER) sites are often the result of extreme meteorological events. Among the events of significance are tropical storms, including hurricanes, and extratropical cyclones. Extratropical storms are low-pressure systems of the middle and high latitudes with their attendant cold and warm fronts. These fronts are associated with strong, horizontal thermal gradients in surface temperatures, strong winds, and a vigorous jet stream aloft. These storms and their attendant fronts generate most of the annual precipitation in the continental United States and provide the lifting mechanisms for thunderstorms that, on occasion, spawn tornadoes. Off the United States West and East Coasts, extratropical storms generate winds, wind waves, wind tides, and long-shore currents that rework coastal sediments, alter landscape morphology, and change the regional patterns of coastal erosion and accretion (Dolan et al. 1988). Although extratropical storms do not match hurricanes in either precipitation intensity or in the strength of the winds generated, they are much larger in size and have a more extensive geographic impact. On occasion, extratropical storms will intensify at an extraordinary rate of 1 millibar (mb) per hour for 24 hours or more. Such storms are classed as “bomb” and are comparable to hurricanes. Extratropical storms occur in all months of the year but are most frequent and more intense in winter when the north-south temperature contrast is large and dynamic support for storm intensification from the stronger jet stream aloft is great. In this chapter, we will explore the history of storminess for those LTER sites in the continental United States at which more than a century of data on storms and their storm tracks are readily available. Specifically, we will look at the record of changes in storminess at both the regional and national scales. During the 1990s, significant storms along the U.S. West Coast and droughts and fires in Florida in an El Niño year led to a hypothesis that El Niño and La Niña conditions were associated with a modulation in the frequency of storms. In addition, it has been suggested that the frequency of El Niño and La Niña events and, by inference, storminess, has increased during the past century.

scholarly journals Long-Term Trends in Root-Zone Soil Moisture across CONUS Connected to ENSO

2020 ◽  
Vol 12 (12) ◽  
pp. 2037
Author(s):  
Kenneth J. Tobin ◽  
Roberto Torres ◽  
Marvin E. Bennett ◽  
Jianzhi Dong ◽  
Wade T. Crow
Keyword(s):  
Soil Moisture ◽  
El Niño ◽  
Root Zone ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Kendall Test ◽  
La Niña ◽  
La Nina

Root zone soil moisture (RZSM) is one of the least-monitored variables within the hydrologic cycle. Given the importance of RZSM to agriculture, more effort is needed to understand the potential impacts of the El Niño southern oscillation (ENSO), Pacific decadal oscillation (PDO), and Atlantic multidecadal oscillation (AMO) on this critical variable. This study focused on the CONtiguous United States (CONUS) RZSM (0 to 40 cm depth) over nearly three decades (1992 to 2018). Basic trend analysis with the Mann–Kendall test and wavelet transform coherence (WTC) was utilized. The RZSM product examined was Soil MERGE (SMERGE 2.0). More CONUS pixels exhibited drying (56 to 75%) versus wetting (25 to 44%) trends between 1992 and 2018. Seasonal wetting trends were observed particularly during winter in the Southwest and Northwest regions associated with El Nino and La Nina episodes, respectively. The noted long-term RZSM trends are more clearly attributable to oceanic-atmospheric teleconnections than global climate change. The most significant result was the strong drying trend in central CONUS reflected a shift to La Nina and cool PDO conditions during the 2000s, further amplified by a change to positive AMO corresponding with this period.

scholarly journals Nonlinear Zonal Wind Response to ENSO in the CMIP5 Models: Roles of the Zonal and Meridional Shift of the ITCZ/SPCZ and the Simulated Climatological Precipitation*

2015 ◽  
Vol 28 (21) ◽  
pp. 8556-8573 ◽  
Author(s):  
Kit-Yan Choi ◽  
Gabriel A. Vecchi ◽  
Andrew T. Wittenberg
Keyword(s):  
Zonal Wind ◽  
Linear Correlation ◽  
El Niño ◽  
El Nino ◽  
Dominant Role ◽  
La Niña ◽  
Cmip5 Models ◽  
Central Pacific ◽  
La Nina ◽  
Wind Response

Abstract The observed equatorial Pacific zonal wind response during El Niño tends to be stronger than during La Niña. Most global coupled climate models in phase 5 of CMIP (CMIP5) exhibit such nonlinearity, although weaker than observed. The wind response nonlinearity can be reproduced by driving a linear shallow water atmospheric model with a model’s or the observed precipitation anomalies, which can be decomposed into two main components: the zonal and meridional redistribution of the climatological precipitation. Both redistributions contribute comparably to the total rainfall anomalies, whereas the zonal redistribution plays the dominant role in the zonal wind response. The meridional redistribution component plays an indirect role in the nonlinear wind response by limiting the zonal redistribution during La Niña and thus enhancing the nonlinearity in the wind response significantly. During La Niña, the poleward movement of the ITCZ/SPCZ reduces the equatorial zonal-mean precipitation available for the zonal redistribution and its resulting zonal wind response. Conversely, during El Niño, the equatorward movement of the ITCZ and SPCZ do not limit the zonal redistribution of precipitation. The linear equatorial zonal wind response to ENSO is found to have a significant linear correlation with the equatorial central Pacific climatological precipitation and SST among the CMIP5 models. However, no linear correlation is found between the nonlinear equatorial zonal wind response and the climatological precipitation.

scholarly journals Long-term potential nonlinear predictability of El Niño–La Niña events

2016 ◽  
Vol 49 (1-2) ◽  
pp. 131-141 ◽  
Author(s):  
H. F. Astudillo ◽  
R. Abarca-del-Río ◽  
F. A. Borotto
Keyword(s):  
El Niño ◽  
El Nino ◽  
La Niña ◽  
La Nina ◽  
Nonlinear Predictability

scholarly journals EFFECT OF LONG TERM TIDAL CONSTITUENTS ON MEAN SEA LEVEL TREND DURING EL-NINO AND LA-NINA PHENOMENA

2017 ◽  
Vol XLII-4/W5 ◽  
pp. 225-234
Author(s):  
N. H. M. Yusof ◽  
M. R. Mahmud ◽  
M. H. Abdullah
Keyword(s):  
El Niño ◽  
El Nino ◽  
La Niña ◽  
The Moon ◽  
Tidal Constituent ◽  
La Nina ◽  
Tidal Data ◽  
The Difference ◽  
Tidal Constituents

There are many factors that influence the change of the tidal constituent pattern. The factors can be classified as astronomical factors and non- astronomical factors. The astronomical factors involve the gravitational force attraction by the moon and sun. The distance of sun and moon influence the gravitational attractions that are produced by the moon and sun towards earth surface. Non-astronomical factors involved the movements of currents, waves, temperature and so on which is cause by the phenomenon such as El-Nino, La-Nina. This study was conducted to investigate the effect of these phenomena towards the pattern of tidal constituent during the phenomenon on several stations that have been chosen. The difference stations were chose due to the change in the position of celestial body. In addition, tidal data for several stations were processed using the UTM Tidal Analysis and Prediction Software (μ-TAPS). Based on the tidal data that has been processed, the graphs were plotted for the predicted data and observed data to compare the different pattern between the data. The tidal data that has been processed were used to analyse the pattern of tidal constituents based on the changing amplitude of M<sub>2</sub>, S<sub>2</sub>, K<sub>1</sub>, O<sub>1</sub>, S<sub>a</sub>, S<sub>sa</sub>, Mm, Mf and MSf.

Population dynamics of Caulerpa sertularioides (Chlorophyta: Bryopsidales) from Baja California, Mexico, during El Niño and La Niña years

2001 ◽  
Vol 81 (5) ◽  
pp. 721-726 ◽  
Author(s):  
Ricardo Scrosati
Keyword(s):  
El Niño ◽  
Baja California ◽  
Sandy Beach ◽  
El Nino ◽  
La Niña ◽  
Eastern Coast ◽  
Population Abundance ◽  
La Nina ◽  
Gelidium Robustum

This study monitored the abundance of the tropical/subtropical seaweed Caulerpa sertularioides (Chlorophyta: Bryopsidales) from a sandy beach from Balandra Cove, on the south-eastern coast of the Baja California Peninsula, Mexico, between April 1998 and April 2000, including consecutive El Niño and La Niña events. El Niño conditions, indicated by relatively high seawater temperatures, were associated with a high population abundance (April–June 1998), whereas La Niña conditions, indicated by relatively low temperatures, were associated with the absence of C. sertularioides (April–June 1999 and April 2000). Caulerpa sertularioides was present during other times of the year during the study period, but never with the high abundance reached during El Niño conditions. Seaweeds of temperate affinity occurring in Baja California, such as Gelidium robustum (Rhodophyta: Gelidiales) and Macrocystis pyrifera (Phaeophyceae: Laminariales), decreased sharply in abundance during El Niño conditions. Therefore, the biogeographic affinity of seaweeds from Baja California might be helpful in predicting the effects of El Niño and La Niña on their abundance, with implications for resource management and for the prediction of the effects of long-term oceanographic changes on seaweed distribution.

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