scholarly journals Inter-annual variability of the Pelagic-Benthic coupling in the upwelling system off central Chile

2006 ◽  
Vol 6 ◽  
pp. 127-132 ◽  
Author(s):  
M. Graco ◽  
D. Gutiérrez ◽  
L. Farías
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Coastal Region ◽  
Euphotic Zone ◽  
Carbon Fluxes ◽  
Water Interface ◽  
Central Chile ◽  
Upwelling System ◽  
Benthic Coupling

Abstract. The coastal region of central Chile (36° S) is one of the most productive coastal systems, characterized by a marked seasonality in the upwelling regime, that brings subsurface waters rich in nutrient and poor in oxygen (ESSW) into the euphotic zone. This oceanographic condition depends basically on the equatorward wind strength and is modified on different time scales, with the El Niño-Southern Oscillation (ENSO) phenomenon as the main source of interannual variability in the Pacific Ocean. Here we present an effort to integrate physical and biogeochemical variability associated with in situ information and experiments at coastal stations off central Chile (36° S) in order to improve the knowledge on the pelagic-benthic coupling in this upwelling system during the warm ENSO phase or El Niño. Carbon fluxes exported from the water column to the sediments and the ammonium exchange across the sediment-water interface are discussed together with oceanographic and benthic conditions. All measurements and estimations were carried out from May 1997 until April 2001 at two stations, one located inside Concepción Bay (~28 m depth), and the other on the continental shelf at ~36° S (~88 m depth). The results show that the pelagic and benthic systems are strongly coupled off central Chile (36° S). Oceanographic variability associated with upwelling events (seasonal scale) and an El Niño event (interannual scale) was observed. The carbon fluxes exported to the sediments, the benthic conditions (i.e., quantity and quality of the sediment organic matter), and the ammonium exchange across the sediment-water interface, responded to the seasonal regime of upwelling during non El Niño years as well as to the ENSO related oceanographic variability.

scholarly journals A first shallow firn-core record from Glaciar La Ollada, Cerro Mercedario, central Argentine Andes

2006 ◽  
Vol 43 ◽  
pp. 14-22 ◽  
Author(s):  
David Bolius ◽  
Margit Schwikowski ◽  
Theo Jenk ◽  
Heinz W. Gäggeler ◽  
Gino Casassa ◽  
...  
Keyword(s):  
El Niño ◽  
Southern Oscillation Index ◽  
El Nino ◽  
Southern Oscillation ◽  
Winter Precipitation ◽  
Time Span ◽  
Paleoclimate Reconstruction ◽  
Central Chile ◽  
Annual Layer ◽  
Firn Core

AbstractIn January 2003, shallow firn cores were recovered from Glaciar Esmeralda on Cerro del Plomo (33°14’S, 70°13’W; 5300 ma.s.l.), central Chile, and from Glaciar La Ollada on Cerro Mercedario (31°58’S, 70°07’W; 6070 ma.s.l.), Argentina, in order to find a suitable archive for paleoclimate reconstruction in a region strongly influenced by the El Nino-Southern Oscillation. In the area between 28°S and 35°S, the amount of winter precipitation is significantly correlated to the Southern Oscillation Index, with higher values during El Nino years. Glaciochemical analysis indicates that the paleo-record at Glaciar La Ollada is well preserved, whereas at Glaciar Esmeralda the record is strongly influenced by meltwater formation and percolation. A preliminary dating of the Mercedario core by annual-layer counting results in a time-span of 17 years (1986-2002), yielding an average annual net accumulation of 0.45 m w.e.

scholarly journals Effects of June winds on rainfall in the coastal region of Kenya

2009 ◽  
Vol 9 (30) ◽  
pp. 1824-1844
Author(s):  
Simon Muti ◽  
◽  
W Ng'etich ◽  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Indian Subcontinent ◽  
Rainfall Variability ◽  
Coastal Region ◽  
La Niña ◽  
Circulation System ◽  
Eastern Region ◽  
La Nina

Although the equatorial Eastern region of Africa is adjacent to the Indian Ocean, it tends to exhibit a drier climate rather than one characterized by abundant tropical rains. A number of studies on rainfall variability in the East African region have tended to suggest a stronger influence of local factors in controlling rainfall amounts and their characteristics rather than the global wind circulation system. A climatic phenomenon that is locally termed “June winds” is unique to East Africa’s coastal region. The study mainly involved analysing rainfall anomalies and means of 39- year meteorological data from the region and data from earlier studies about the region. The results indicate that June winds occur annually after the onset of long rains between the months of May and June. They impart subsidence, drying and cloud free conditions, altering the climatological properties in the areas they traverse. The attainment of peak June wind velocities causes a characteristic depression in rainfall probability and amounts on their course, similar to the ‘Ganges depression’ of temperatures in the Indian subcontinent, which in turn affects available soil moisture for crop growth. The results also reveal existence of years of “above-normal rains” (herein referred to as El Niño years) and years of “below-normal rains” (herein referred to as La Niña years) which are associated and modulated by El Niño southern oscillation. They also reveal that drought years tend to occur in succession and that the June winds tend to be suppressed or absent during El Niño years, but strongly associate with La Niña years. The study suggests that the frequency and therefore the ratio of La Niña years to El Niño years have been increasing. The study also suggests possibility of developing a decision support system for farmers in resource use and allocation based predicted time of occurrence of the June winds.

Soil Moisture Variability Intensifies and Prolongs Eastern Amazon Temperature and Carbon Cycle Response to El Niño–Southern Oscillation

2019 ◽  
Vol 32 (4) ◽  
pp. 1273-1292 ◽  
Author(s):  
Paul A. Levine ◽  
James T. Randerson ◽  
Yang Chen ◽  
Michael S. Pritchard ◽  
Min Xu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Carbon Cycle ◽  
El Niño ◽  
Indirect Effects ◽  
El Nino ◽  
Southern Oscillation ◽  
Carbon Fluxes ◽  
Soil Moisture Variability ◽  
Sst Anomalies ◽  
Moisture Variability

El Niño–Southern Oscillation (ENSO) is an important driver of climate and carbon cycle variability in the Amazon. Sea surface temperature (SST) anomalies in the equatorial Pacific drive teleconnections with temperature directly through changes in atmospheric circulation. These circulation changes also impact precipitation and, consequently, soil moisture, enabling additional indirect effects on temperature through land–atmosphere coupling. To separate the direct influence of ENSO SST anomalies from the indirect effects of soil moisture, a mechanism-denial experiment was performed to decouple their variability in the Energy Exascale Earth System Model (E3SM) forced with observed SSTs from 1982 to 2016. Soil moisture variability was found to amplify and extend the effects of SST forcing on eastern Amazon temperature and carbon fluxes in E3SM. During the wet season, the direct, circulation-driven effect of ENSO SST anomalies dominated temperature and carbon cycle variability throughout the Amazon. During the following dry season, after ENSO SST anomalies had dissipated, soil moisture variability became the dominant driver in the east, explaining 67%–82% of the temperature difference between El Niño and La Niña years, and 85%–91% of the difference in carbon fluxes. These results highlight the need to consider the interdependence between temperature and hydrology when attributing the relative contributions of these factors to interannual variability in the terrestrial carbon cycle. Specifically, when offline models are forced with observations or reanalysis, the contribution of temperature may be overestimated when its own variability is modulated by hydrology via land–atmosphere coupling.

VARIABILIDAD CLIMÁTICA, CAMBIO CLIMÁTICO Y PESQUERÍAS EN EL ECUADOR.

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Johnny Chavarría Viteri ◽  
Dennis Tomalá Solano
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Pacific Decadal Oscillation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Current Action ◽  
Palabras Clave

La variabilidad climática es la norma que ha modulado la vida en el planeta. Este trabajo demuestra que las pesquerías y acuicultura costera ecuatorianas no son la excepción, puesto que tales actividades están fuertemente influenciadas por la variabilidad ENSO (El Niño-Oscilación del Sur) y PDO (Oscilación Decadal del Pacífico), planteándose que la señal del cambio climático debe contribuir a esta influencia. Se destaca también que, en el análisis de los efectos de la variabilidad climática sobre los recursos pesqueros, el esfuerzo extractivo también debe ser considerado. Por su parte, la acción actual de la PDO está afectando la señal del cambio climático, encontrándose actualmente en fases opuestas. Se espera que estas señales entren en fase a finales de esta década, y principalmente durante la década de los 20 y consecuentemente se evidencien con mayor fuerza los efectos del Cambio Climático. Palabras Clave: Variabilidad Climática, Cambio Climático, ENSO, PDO, Pesquerías, Ecuador. ABSTRACT Climate variability is the standard that has modulated life in the planet. This work shows that the Ecuadorian  fisheries and aquaculture are not the exception, since such activities are strongly influenced by ENSO variability (El Niño - Southern Oscillation) and PDO (Pacific Decadal Oscillation), considering that the signal of climate change should contribute to this influence. It also emphasizes that in the analysis of the effects of climate variability on the fishing resources, the extractive effort must also be considered. For its part, the current action of the PDO is affecting the signal of climate change, now found on opposite phases. It is hoped that these signals come into phase at the end of this decade, and especially during the decade of the 20’s and more strongly evidencing the effects of climate change. Keywords: Climate variability, climate change, ENSO (El Niño - Southern Oscillation) and PDO  (Pacific Decadal Oscillation); fisheries, Ecuador. Recibido: mayo, 2012Aprobado: agosto, 2012

Rendimento de grãos de soja e de milho, no Rio Grande do Sul, não difere entre eventos El Niño Oscilação Sul

Agrometeoros ◽  
2018 ◽  
Vol 26 (1) ◽  
Author(s):  
Ronaldo Matzenauer ◽  
Bernadete Radin ◽  
Alberto Cargnelutti Filho
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rio Grande ◽  
La Niña ◽  
Rio Grande Do Sul ◽  
La Nina ◽  
Significant Difference ◽  
Income Data ◽  
The Relationship

O objetivo deste trabalho foi avaliar a relação entre o fenômeno El Niño Oscilação Sul - ENOS e o rendimento de grãos de soja e de milho no Rio Grande do Sul e verificar a hipótese de que os eventos El Niño são favoráveis e os eventos La Niña são prejudiciais ao rendimento de grãos das culturas. Foram utilizados dados de rendimento de grãos dos anos agrícolas de 1974/75 a 2016/17, e relacionados com as ocorrências de eventos ENOS. Foram analisados os dados de rendimento observados na colheita e os dados estimados com a remoção da tendência tecnológica. Os resultados mostraram que não houve diferença significativa do rendimento médio de grãos de soja e de milho na comparação entre os eventos ENOS. Palavras-chave: El Niño, La Niña, safras agrícolas. Abstract – The objective of this work was to evaluate the relationship between the El Niño Southern Oscillation (ENSO) phenomenon with the grain yield of soybean and maize in Rio Grande do Sul state, Brazil and to verify the hypothesis that the El Niño events are favorable and the La Niña events are harmful to the culture’s grain yields. Were used data from the agricultural years of 1974/75 to 2016/17, and related to the occurrence of ENOS events. We analyzed income data observed at harvest and estimated data with technological tendency was removed. The results showed that there was no significant difference in the average yield of soybeans and corn in the comparison between events.

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