El Niño and World Primary Commodity Prices : Warm Water or Hot Air?

Abstract Altimetric observations of sea surface height anomaly (SSHA) from the TOPEX/Poseidon and ERS satellites, hydrography, and the ECMWF and Florida State University wind products are used to track warm water (≥20°C) as it is exchanged between the equatorial Pacific Ocean and the higher latitudes during 1993–2003. The large El Niño event of 1997–98 resulted in a significant discharge of warm water toward the higher latitudes within the interior of the Pacific Ocean. The exchange of anomalous warm water volume with the Northern Hemisphere appears to be blocked under the intertropical convergence zone, consistent with most current ideas on the time-mean tropical–subtropical exchange. Little of the warm water discharged northward across 5° and 8°N during the 1997–98 El Niño event could be traced as far as 10°N. To the south, however, these anomalous volumes of warm water were visible at least as far as 20°S, primarily in the longitudes around 130°–160°W. In both hemispheres most of the warm water appeared to flow westward before returning to the Tropics during the recharge phase of the El Niño–La Niña cycle. The buildup of warm water in the Tropics before the 1997–98 El Niño is shown to be fed primarily by warm water drawn from the region in the western Pacific within 5°S–15°N. The exchange cycle between the equatorial band and the higher latitudes north of the equator leads the cycle in the south by 6–8 months. These results are found in all three datasets used herein, hydrography, altimetric observations of SSHA, and Sverdrup transports calculated from multiple wind products, which demonstrates the robustness of the results.

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El Nino spells multiple humanitarian crises for Africa

Emerald Expert Briefings ◽

10.1108/oxan-db207392 ◽

2015 ◽

Keyword(s):

El Niño ◽

El Nino ◽

Commodity Prices ◽

Sub Saharan Africa ◽

Weather System ◽

Content Type ◽

Humanitarian Crises ◽

Cocoa Production ◽

Sub Saharan ◽

The Impact

Subject Outlook for El Nino in sub-Saharan Africa. Significance The current El Nino weather system, one of the three strongest since 1950, is causing drought in some areas and flooding in others. Past instances have resulted in significant drops in agricultural production, livestock deaths, infrastructure damage and lost income. Together with likely higher incidence of disease, similar effects could trigger humanitarian crises across sub-Saharan Africa (SSA). Impacts Poor sanitation infrastructure in many major SSA cities will facilitate the spread of water-borne diseases such as cholera. In Southern Africa, strong institutions overseeing intra-regional water sharing will limit prospects for diplomatic disputes over water. Unusual rain and wind patterns in West Africa could curb cocoa production, creating shortages that will push up global prices. Likely lower agricultural output across SSA will compound the impact of low commodity prices on cooling GDP growth.

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On the Physics of the Warm Water Volume and El Niño/La Niña Predictability

Journal of Physical Oceanography ◽

10.1175/jpo-d-18-0144.1 ◽

2019 ◽

Vol 49 (6) ◽

pp. 1541-1560 ◽

Cited By ~ 3

Author(s):

Allan J. Clarke ◽

Xiaolin Zhang

Keyword(s):

El Niño ◽

El Nino ◽

Warm Pool ◽

Equatorial Pacific ◽

La Niña ◽

Warm Water ◽

Water Volume ◽

La Nina ◽

Eastern Equatorial Pacific ◽

Warm Water Volume

AbstractPrevious work has shown that warm water volume (WWV), usually defined as the volume of equatorial Pacific warm water above the 20°C isotherm between 5°S and 5°N, leads El Niño. In contrast to previous discharge–recharge oscillator theory, here it is shown that anomalous zonal flow acceleration right at the equator and the movement of the equatorial warm pool are crucial to understanding WWV–El Niño dynamics and the ability of WWV to predict ENSO. Specifically, after westerly equatorial wind anomalies in a coupled ocean–atmosphere instability push the warm pool eastward during El Niño, the westerly anomalies follow the warmest water south of the equator in the Southern Hemisphere summer in December–February. With the wind forcing that causes El Niño in the eastern Pacific removed, the eastern equatorial Pacific sea level and thermocline anomalies decrease. Through long Rossby wave dynamics this decrease results in an anomalous westward equatorial flow that tends to push the warm pool westward and often results in the generation of a La Niña during March–June. The anomalously negative eastern equatorial Pacific sea level typically does not change as much during La Niña, the negative feedback is not as strong, and El Niños tend to not follow La Niñas the next year. This El Niño/La Niña asymmetry is seen in the WWV/El Niño phase diagram and decreased predictability during “La Niña–like” decades.

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ENSO and sandy beach macrobenthos of the tropical East Pacific: some speculations

Advances in Geosciences ◽

10.5194/adgeo-6-57-2006 ◽

2006 ◽

Vol 6 ◽

pp. 57-61 ◽

Cited By ~ 1

Author(s):

T. Vanagt ◽

E. Beekman ◽

M. Vincx ◽

S. Degraer

Keyword(s):

El Niño ◽

Sandy Beach ◽

El Nino ◽

Water System ◽

La Niña ◽

Warm Water ◽

Enso Cycle ◽

Marine Biota ◽

La Nina ◽

Normal Period

Abstract. The influence of the ENSO cycle on marine fauna and flora has only recently been given the attention it deserves. The very strong 1997–1998 El Niño and its obvious effects on marine biota was a key point in ENSO research, but unfortunately few quantitative data about the 1997–1998 El Niño itself are available. To gather information about the effect of ENSO on the macrobenthos, we performed a bi-weekly transect monitoring on an Ecuadorian sandy beach in 2000–2001, during the strong La Niña following the 1997–1998 El Niño, and in the normal period of 2002–2004. In this paper, intertidal macrofaunal densities at higher taxonomic level are used to compare a La Niña phase with the 'normal' situation. The few existing documents about El Niño and sandy beach macrobenthos, and scattered data from previous and current research, were used to complete the picture. Total macrobenthos densities were 300% lower during the La Niña phase compared with equal months in the normal phase. Especially Crustacea and Mollusca showed a marked increase in densities towards the normal situation (94% and 341% respectively). Polychaeta and Echinodermata, however, showed higher densities during the La Niña phase (22% and 73% respectively). Two possible explanations are proposed. (1) Low densities during the La Niña could be due to the very strong preceding El Niño, suggesting the populations were still recovering. This hypothesis is supported by previous work done in the south of Peru. This is, however, a cold water system, compared to the Ecuadorian warm water system. (2) The second hypothesis states that a La Niña will have a very severe impact on the intertidal macrofauna of a warm water system like the Ecuadorian coast.

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