scholarly journals Coastal upwelling along the southwest coast of India – ENSO modulation

2008 ◽  
Vol 26 (6) ◽  
pp. 1331-1334 ◽  
Author(s):  
K. Muni Krishna
Keyword(s):  
Coastal Upwelling ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Trade Winds ◽  
Southwest Coast Of India ◽  
Southwest Coast ◽  
Enso Events ◽  
The Pacific ◽  
Basin Scale ◽  
Using Data

Abstract. An index of El Niño Southern Oscillation (ENSO) in the Pacific during pre monsoon season is shown to account for a significant part of the variability of coastal Sea Surface Temperature (SST) anomalies measured a few months later within the wind driven southwest coast of India coastal upwelling region 7° N–14° N. This teleconnection is thought to result from an atmospheric bridge between the Pacific and north Indian Oceans, leading to warm (cold) ENSO events being associated with relaxation (intensification) of the Indian trade winds and of the wind-induced coastal upwelling. This ENSO related modulation of the wind-driven coastal upwelling appears to contribute to the connection observed at the basin-scale between ENSO and SST in the Arabian Sea. The ability to use this teleconnection to give warning of large changes in the southwest coast of India coastal upwelling few months in advance is successfully tested using data from 1998 and 1999 ENSO events.

scholarly journals Coastal upwelling along the southwest coast of India – ENSO modulation

2008 ◽  
Vol 5 (1) ◽  
pp. 123-134 ◽  
Author(s):  
K. Muni Krishna ◽  
V. Kovačević ◽  
M. Gačić
Keyword(s):  
Coastal Upwelling ◽  
Southern Oscillation ◽  
Trade Winds ◽  
Southwest Coast Of India ◽  
Southwest Coast ◽  
Enso Events ◽  
The Pacific ◽  
Basin Scale ◽  
Coastal Sea ◽  
Using Data

Abstract. An index of El Niño Southern Oscillation (ENSO) in the Pacific during pre monsoon is shown to account for a significant part of the variability of coastal Sea Surface Temperature (SST) anomalies measured a few months later within the wind driven southwest coast of India coastal upwelling region 7° N–14° N. This teleconnection is thought to result from an atmospheric bridge between the Pacific and north Indian Oceans, leading to warm (cold) ENSO events being associated with relaxation (intensification) of the Indian trade winds and of the wind-induced coastal upwelling. This ENSO related modulation of the wind-driven coastal upwelling appears to contribute to the connection observed at the basin-scale between ENSO and SST in the Arabian Sea. The ability to use this teleconnection to give warning of large changes in the southwest coast of India coastal upwelling few months in advance is successfully tested using data from 1998 and 1999 ENSO events.

scholarly journals A re-examination of ENSO/ anti-ENSO events and simultaneous performance of the Indian summer monsoon

MAUSAM ◽  
2021 ◽  
Vol 47 (1) ◽  
pp. 59-66
Author(s):  
J. CHATTOPADHYAY ◽  
R. BHATLA
Keyword(s):  
Monsoon Rainfall ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Strong Association ◽  
Enso Events ◽  
The Pacific ◽  
Degree Of Confidence ◽  
High Degree ◽  
The Relationship ◽  
Very High

The relationship between ENSO/anti-ENSO events in the Pacific basin and simultaneous all India monsoon has been re-examined for the period 1901-1990 using Southern Oscillation Index (SOI). The result shows that there is fairly strong association between ENSO events and dry monsoon years. There exists a weak teleconnection between anti-ENSO events and wet monsoon indicating that anti-ENSO events have only a moderate impact on the Indian monsoon rainfall. Developing ENSO (anti-ENSO) episodes during the monsoon season indicates non-occurrence of simultaneous floods (droughts) with a very high degree of confidence 70 (50) percent of the droughts (floods) during the above period have occurred during ENSO (anti-ENSO) events indicating that extreme monsoon activities in the form of droughts (floods) might be important factors for the occurrence of simultaneous ENSO/anti-ENSO events.

Occurrence of a multi-species diatom bloom dominated by Proboscia alata (Brightwell) Sandstorm along the southwest coast of India

2013 ◽  
Vol 42 (1) ◽  
Author(s):  
Lathika Cicily ◽  
K. Padmakumar ◽  
C. Asha Devi ◽  
V. Sanjeevan
Keyword(s):  
Cell Density ◽  
Coastal Waters ◽  
Monsoon Season ◽  
Late Summer ◽  
Nutrient Concentrations ◽  
Diatom Bloom ◽  
Southwest Coast Of India ◽  
Southwest Coast ◽  
Toxic Species ◽  
A Cell

AbstractThe present communication reports on the occurrence of a multi-species diatom bloom in the upwelled waters along the southwest coast of India. During the late summer monsoon season (September 2009) a multi-species diatom bloom with a pale green discoloration of the sea surface was observed in the coastal waters of southwest coast of India. The bloom spread over an area of approximately 15 km2 along the coastal waters off Kannur (Lat. 11°59.471 N, Long. 75°03.446 E). Total diatom cell density of the bloom area was 16 × 104 cells l−1. Proboscia (=Rhizosolenia) alata (Brightwell) Sandstrom constituted 90% of the total phytoplankton population. Other phytoplankton groups that contributed to the bloom population included Chaetoceros spp., Pseudo-nitzschia spp., Rhizosolenia spp., Coscinodiscus sp., Leptocylindrus danicus, Thalassiosira sp., and Bacteriosira sp. Among these Pseudo-nitzschia multiseries, a toxic species with the ability to produce potent neurotoxin domoic acid, was observed with a cell density of 4 × 103 cells l−1. Surface chlorophyll a concentration of the bloom region was 14.1 μg l−1. Nutrient concentrations of the bloom area were 0.01 μmol l−1 for NO2-N, 0.1 μmol l−1 for NO3-N, 0.83 μmol l−1 for PO4-P and 11.44 μmol l−1 for SiO4.

scholarly journals LINEARIZATION OF RELATIVE HUMIDITY OVER THE PACIFIC OCEAN ON THE EQUATORIAL LINE

2019 ◽  
Vol 16 (33) ◽  
pp. 630-640
Author(s):  
C. M. DÍEZ ◽  
C. J. SOLANO
Keyword(s):  
Pacific Ocean ◽  
Relative Humidity ◽  
Earth Science ◽  
Southern Oscillation ◽  
Correlation Coefficients ◽  
East Side ◽  
The West ◽  
Enso Events ◽  
The Pacific ◽  
The Pacific Ocean

The atmosphere system is ruled by the interaction of many meteorological parameters, causing a dependency between them, i.e., moisture and temperature, both suitable in front of any anomaly, such as storms, hurricanes, El Niño-Southern Oscillation (ENSO) events. So, understanding perturbations of the variation of moistness along the time may provide an indicator of any oceanographic phenomenon. Annual relative humidity data around the Equatorial line of the Pacific Ocean were processed and analyzed to comprehend the time evolution of each dataset, appreciate anomalies, trends, histograms, and propose a way to predict anomalous episodes such ENSO events, observing abnormality of lag correlation coefficients between every pair of buoys. Datasets were taken from the Tropical Atmosphere Ocean / Triangle Trans-Ocean Network (TAO/TRITON) project, array directed by Pacific Environmental Laboratory (PMEL) of the National Oceanic and Atmospheric Administration (NOAA), and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). All the datasets were processed, and the code was elaborated by the author or adapted from Mathworks Inc. Even occurrences of relative humidity in the east side of the Pacific Ocean seem to oscillate harmonically, while occurrences in the west side, do not, because of the size of their amplitudes of oscillations. This fact can be seen in the histograms that show Peak shapes in the east side of the ocean, and Gaussians in the west; lag correlation functions show that no one pair of buoys synchronize fluctuations, but western buoys are affected in front of ENSO events, especially between 1997-98. Definitely, lag correlations in western buoys are determined to detect ENSO events.

On the influence of ENSO complexity on Pan-Pacific coastal wave extremes

2021 ◽  
Vol 118 (47) ◽  
pp. e2115599118
Author(s):  
Julien Boucharel ◽  
Rafael Almar ◽  
Elodie Kestenare ◽  
Fei-Fei Jin
Keyword(s):  
Southern Oscillation ◽  
Wave Activity ◽  
Spatial Behavior ◽  
Coastal Hazards ◽  
Climate Control ◽  
Enso Events ◽  
The Pacific ◽  
Coastal Impacts ◽  
Climate Mode

Wind-generated waves are dominant drivers of coastal dynamics and vulnerability, which have considerable impacts on littoral ecosystems and socioeconomic activities. It is therefore paramount to improve coastal hazards predictions through the better understanding of connections between wave activity and climate variability. In the Pacific, the dominant climate mode is El Niño Southern Oscillation (ENSO), which has known a renaissance of scientific interest leading to great theoretical advances in the past decade. Yet studies on ENSO’s coastal impacts still rely on the oversimplified picture of the canonical dipole across the Pacific. Here, we consider the full ENSO variety to delineate its essential teleconnection pathways to tropical and extratropical storminess. These robust seasonally modulated relationships allow us to develop a mathematical model of coastal wave modulation essentially driven by ENSO’s complex temporal and spatial behavior. Accounting for this nonlinear climate control on Pan-Pacific wave activity leads to a much better characterization of waves’ seasonal to interannual variability (+25% in explained variance) and intensity of extremes (+60% for strong ENSO events), therefore paving the way for significantly more accurate forecasts than formerly possible with the previous baseline understanding of ENSO’s influence on coastal hazards.

scholarly journals Coccolithophore response to climate and surface hydrography in Santa Barbara Basin, California, AD 1917–2004

2009 ◽  
Vol 6 (10) ◽  
pp. 2025-2039 ◽  
Author(s):  
M. Grelaud ◽  
A. Schimmelmann ◽  
L. Beaufort
Keyword(s):  
Southern Oscillation ◽  
California Current ◽  
Santa Barbara ◽  
Santa Barbara Basin ◽  
Enso Events ◽  
The Pacific ◽  
Hydrographic Conditions ◽  
Shell Carbonate ◽  
Relative Abundances ◽  
Counter Current

Abstract. The varved sedimentary AD 1917–2004 record from the depositional center of the Santa Barbara Basin (SBB, California) was analyzed with monthly to triannual resolution to yield relative abundances of six coccolithophore species representing at least 96% of the coccolithophore assemblage. Seasonal/annual relative abundances respond to climatic and surface hydrographic conditions in the SBB, whereby (i) the three species G. oceanica, H. carteri and F. profunda are characteristic of the strength of the northward flowing warm California Counter Current, (ii) the two species G. ericsonii and G. muellerae are associated with the cold equatorward flowing California Current, (iii) and E. huxleyi appears to be endemic to the SBB. Spectral analyses on relative abundances of these species show that all are influenced by the El Niño Southern Oscillation (ENSO) and/or by the Pacific Decadal Oscillation (PDO). Increased relative abundances of G. oceanica and H. carteri are associated with warm ENSO events, G. muellerae responds to warm PDO events and the abundance of G. ericsonii increases during cold PDO events. Morphometric parameters measured on E. huxleyi, G. muellerae and G. oceanica indicate increasing coccolithophore shell carbonate mass from ~1917 until 2004 concomitant with rising pCO2 and sea surface temperature in the region of the SBB.

Environment: the key to understanding the South African chokka squid (Loligo vulgaris reynaudii) life cycle and fishery?

1994 ◽  
Vol 6 (2) ◽  
pp. 249-258 ◽  
Author(s):  
M.J. Roberts ◽  
W.H.H. Sauer
Keyword(s):  
Life Cycle ◽  
Coastal Upwelling ◽  
Environmental Variability ◽  
Southern Oscillation ◽  
The South ◽  
Enso Events ◽  
Loligo Vulgaris ◽  
Large Fluctuations ◽  
High Turbidity ◽  
Physical And Chemical

This paper explores effects of environmental variability on the life cycle of the chokka squid, Loligo vulgaris reynaudii in South Africa, particularly the effect of physical and chemical influences on adult distribution, and the availability of spawning aggregations to the local jig fishery. The following hypotheses are presented: 1) temperature, dissolved oxygen and currents have a direct effect on the demersal distribution of adult chokka on the feeding grounds, but this is restricted to the west coast where environmental conditions are more extreme relative to the south coast, 2) chokka catches increase in proportion to the extent of coastal upwelling, 3) spawning behavior along the inshore regions (<50m) is strongly influenced by turbidity near the seabed. High turbidity forces the spawning popuation to lay their eggs in deeper waters, and are thus not available to the jig fishery. 4) El Niño – Southern Oscillation (ENSO) events are linked with large fluctuations in the availability of spawning squid aggregations to the inshore jig fishery.

Impact of the Quasi-Biennial Oscillation on the boreal winter tropospheric circulation in CMIP5/6 models

2020 ◽  
Author(s):  
Jian Rao ◽  
Chaim Garfinkel ◽  
Ian White ◽  
Chen Schwartz
Keyword(s):  
Pacific Ocean ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Buoyancy Frequency ◽  
Maritime Continent ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Enso Events ◽  
The Pacific ◽  
Biennial Oscillation

&lt;p&gt;Using 17 CMIP5/6 models with a spontaneously-generated quasi-biennial oscillation (QBO)-like phenomenon, this study explores and evaluates three dynamical pathways for impacts of the QBO on the troposphere: (i) the Holtan-Tan (HT) effect on the stratospheric polar vortex and the northern annular mode (NAM), (ii) the subtropical zonal wind downward arching over the Pacific, and (iii) changes in local convection over the Maritime Continent and Indo-Pacific Ocean. More than half of the models can reproduce at least one of the three pathways, but few models can reproduce all of the three routes. Firstly, most models are able to simulate a weakened polar vortex during easterly QBO (EQBO) winters, in agreement with the observed HT effect. However, the weakened polar vortex response during EQBO winters is underestimated or not present at all in other models, and hence the QBO &amp;#8594; vortex &amp;#8594; tropospheric NAM/AO chain is not simulated. For the second pathway associated with the downward arching of the QBO winds, seven models incorrectly or poorly simulate the extratropical easterly anomaly center over 20&amp;#8211;40&amp;#176;N in the Pacific sector during EQBO, and hence the negative relative vorticity anomalies poleward of the easterly center is not resolved in those models, leading to an underestimated or incorrectly modelled height response over North Pacific. However the other ten do capture this effect. The third pathway is only observed in the Indo-Pacific Ocean, where the strong climatological deep convection and the warm pool are situated. Nine models can simulate the convection anomalies associated with the QBO over the Maritime Continent, which is likely caused by the near-tropopause low buoyancy frequency anomalies. No robust relationship between the QBO and El Ni&amp;#241;o&amp;#8211;Southern Oscillation (ENSO) events can be established using the ERA-Interim reanalysis, and nine models consistently confirm little modulation of the ocean basin-wide Walker circulation and ENSO events by the QBO.&lt;/p&gt;

scholarly journals PDO–ENSO Effects in the Climate of Mexico

2006 ◽  
Vol 19 (24) ◽  
pp. 6433-6438 ◽  
Author(s):  
Edgar G. Pavia ◽  
Federico Graef ◽  
Jorge Reyes
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Climate Anomalies ◽  
Enso Events ◽  
La Nina ◽  
Mean Temperature ◽  
The Pacific

Abstract The role of the Pacific decadal oscillation (PDO) in El Niño–Southern Oscillation (ENSO)-related Mexican climate anomalies during winter and summer is investigated. The precipitation and mean temperature data of approximately 1000 stations throughout Mexico are considered. After sorting ENSO events by warm phase (El Niño) and cold phase (La Niña) and prevailing PDO phase: warm or high (HiPDO) and cold or low (LoPDO), the authors found the following: 1) For precipitation, El Niño favors wet conditions during summers of LoPDO and during winters of HiPDO. 2) For mean temperature, cooler conditions are favored during La Niña summers and during El Niño winters, regardless of the PDO phase; however, warmer conditions are favored by the HiPDO during El Niño summers.

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