Pricing rainfall derivatives in the equatorial Pacific

2020 ◽  
Vol 80 (4) ◽  
pp. 589-608
Author(s):  
Sergio Cabrales ◽  
Jesus Solano ◽  
Carlos Valencia ◽  
Rafael Bautista
Keyword(s):  
El Niño ◽  
Linear Models ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Daily Rainfall ◽  
Equatorial Pacific ◽  
Gamma Model ◽  
Content Type ◽  
International Research Institute

PurposeIn the equatorial Pacific, rainfall is affected by global climate phenomena, such as El Niño Southern Oscillation (ENSO). However, current publicly available methodologies for valuing weather derivatives do not account for the influence of ENSO. The purpose of this paper is to develop a complete framework suitable for valuing rainfall derivatives in the equatorial Pacific.Design/methodology/approachIn this paper, we implement a Markov chain for the occurrence of rain and a gamma model for the conditional quantities using vector generalized linear models (VGLM). The ENSO forecast probabilities reported by the International Research Institute for Climate and Society (IRI) are included as independent variables using different alternatives. We then employ the Esscher transform to price rainfall derivatives.FindingsThe methodology is applied and calibrated using the historical rainfall data collected at the El Dorado airport weather station in Bogotá. All the estimated coefficients turn out to be significant. The results prove more accurate than those of Markovian gamma models based on purely statistical descriptions of the daily rainfall probabilities.Originality/valueThis procedure introduces the novelty of incorporating variables related to the climatic phenomena, which are the forecast probabilities regularly published for the occurrence of El Niño and La Niña.

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 The El Niño: A Meteorological Risk Factor for Vector-borne Diseases

2021 ◽  
Author(s):  
Avi Patel ◽  
Keyword(s):  
El Niño ◽  
Neglected Tropical Diseases ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Economic Loss ◽  
Tropical Diseases ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Climate Crisis

The El Niño Southern Oscillation (ENSO) has been ravaging numerous coastal and inland communities with excessive flooding and drought conditions, causing immense economic loss, and the incidence of many neglected tropical diseases. Affecting over 60 million people directly, El Niño remains one of the greatest enigmas to human health, and combined with the ever-escalating global climate crisis, El Niño events are only projected to increase in magnitude in the coming years (WHO, 2016).

scholarly journals The Impact of Obliquity Change on El Niño Southern Oscillation (ENSO) and La Niña Climate Episodes

2022 ◽  
Author(s):  
Paul C. Rivera
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Global Climate Model ◽  
La Niña ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
La Nina ◽  
The Impact

An alternative physical mechanism is proposed to describe the occurrence of the episodic El Nino Southern Oscillation (ENSO) and La Nina climatic phenomena. This is based on the earthquake-perturbed obliquity change (EPOCH) model previously discovered as a major cause of the global climate change problem. Massive quakes impart a very strong oceanic force that can move the moon which in turn pulls the earth’s axis and change the planetary obliquity. Analysis of the annual geomagnetic north-pole shift and global seismic data revealed this previously undiscovered force. Using a higher obliquity in the global climate model EdGCM and constant greenhouse gas forcing showed that the seismic-induced polar motion and associated enhanced obliquity could be the major mechanism governing the mysterious climate anomalies attributed to El Nino and La Nina cycles.

scholarly journals THE SOUTHERN OSCILLATION, EQUATORIAL PACIFIC ANOMALIES AND EL NIÑO

1975 ◽  
Vol 15 (4) ◽  
pp. 327-353
Author(s):  
WILLIAM H. QUINN ◽  
DAVID O. ZOPF
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Equatorial Pacific ◽  
Easter Island ◽  
El Sistema

Ciertos índices de presión (diferencias en presión atmosférica a nivel del mar entre Easter Island y Darwin, Australia y entre la Isla Juan Fernández y Darwin) delineados como promedios consecutivos de 12 meses, fueron previamente utilizados para caracterizar la oscilación del sur y para monitorear y predecir cambios significativos oceánicos-atmosféricos en el Pacífico Ecuatorial, incluyendo las ocurrencias de El Niño. El valor de utilizar índices de presión adicionales para estos propósitos se explora aquí. Ya que el interés primario son los cambios sobre el Pacífico, Darwin se usa para representar el centro ecuatorial indonesio de baja presión, pero localidades adicionales (Totegegie, Rapa y Tahiti) se usaron a lo largo de la cresta subtropical del Pacífico Sur. En general, hay una consistencia marcada entre las tendencias de los diversos índices; sin embargo, en algunas ocasiones, los puntos de inflexión pueden ser apreciados con varios meses de anticipación cuando se usa una posición de la cresta en lugar de otra y la amplitud de los picos y vaguadas en los índices es a menudo mucho mayor cuando se usa un sitio particular de la cresta. Promedios consecutivos de 3 y 6 meses de los índices que retienen tanto el ciclo anual regular como la fluctuación irregular interanual, son usados aquí para mostrar la importancia de relaciones de fase entre estas 2 fluctuaciones en la determinación de la intensidad de desarrollos anómalos. En el caso poco común de El Niño en 1972, los picos de las 2 fluctuaciones estaban en fase al inicio de 1971 y sus vaguadas estaban en fase a mediados de 1972, de modo que una caída de 14 mb en los promedios consecutivos de 3 meses del índice Darwin oriental, ocurrió sobre un periodo de 18 meses. Esto indica un marcado debilitamiento del sistema de vientos alisios del sureste, que nosotros creemos que es un factor causal del evento severo de 1972. En el evento subsecuente de 1975, el periodo de la oscilación austral se acortó, y aunque las cimas de las 2 fluctuaciones estaban en fase, las vaguadas no lo estaban; por consiguiente, el grado de relajación estaba limitado y resultó un evento débil. Se presenta evidencia adicional para apoyar una relación estrecha entre el sistema de alisios del sureste, modificado por la oscilación austral, y las condiciones anómalas oceanográficas y meteorológicas en el Pacífico ecuatorial.

scholarly journals The impact of the 2015/2016 El Niño on global photosynthesis using satellite remote sensing

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170409 ◽  
Author(s):  
Xiangzhong Luo ◽  
Trevor F. Keenan ◽  
Joshua B. Fisher ◽  
Juan-Carlos Jiménez-Muñoz ◽  
Jing M. Chen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Carbon Cycle ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Carbon Sink ◽  
Global Climate ◽  
Prognostic Models ◽  
Positive Anomaly ◽  
The Impact

The El Niño-Southern Oscillation exerts a large influence on global climate regimes and on the global carbon cycle. Although El Niño is known to be associated with a reduction of the global total land carbon sink, results based on prognostic models or measurements disagree over the relative contribution of photosynthesis to the reduced sink. Here, we provide an independent remote sensing-based analysis on the impact of the 2015–2016 El Niño on global photosynthesis using six global satellite-based photosynthesis products and a global solar-induced fluorescence (SIF) dataset. An ensemble of satellite-based photosynthesis products showed a negative anomaly of −0.7 ± 1.2 PgC in 2015, but a slight positive anomaly of 0.05 ± 0.89 PgC in 2016, which when combined with observations of the growth rate of atmospheric carbon dioxide concentrations suggests that the reduction of the land residual sink was likely dominated by photosynthesis in 2015 but by respiration in 2016. The six satellite-based products unanimously identified a major photosynthesis reduction of −1.1 ± 0.52 PgC from savannahs in 2015 and 2016, followed by a highly uncertain reduction of −0.22 ± 0.98 PgC from rainforests. Vegetation in the Northern Hemisphere enhanced photosynthesis before and after the peak El Niño, especially in grasslands (0.33 ± 0.13 PgC). The patterns of satellite-based photosynthesis ensemble mean were corroborated by SIF, except in rainforests and South America, where the anomalies of satellite-based photosynthesis products also diverged the most. We found the inter-model variation of photosynthesis estimates was strongly related to the discrepancy between moisture forcings for models. These results highlight the importance of considering multiple photosynthesis proxies when assessing responses to climatic anomalies. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

El Niño and the Nomads: Global Climate, Local Environment, and the Crisis of Pastoralism in Late Ottoman Kurdistan

2020 ◽  
Vol 63 (3) ◽  
pp. 316-356
Author(s):  
Zozan Pehlivan
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Local Environment ◽  
Premature Death ◽  
Social Consequences ◽  
Late Nineteenth Century ◽  
Severe Drought ◽  
Climatic Fluctuations

Abstract This article explores the impacts of environmental crises on pastoral nomads in Ottoman Kurdistan/Armenia in the late nineteenth-century. It demonstrates that the climatic fluctuations characterizing these environmental crises were synchronized with global climatic oscillations, specifically the El Niño Southern Oscillation. Recurrent episodes of severe drought and cold dramatically affected these groups, who were unable to withstand extreme changes in temperature and precipitation. Back-to-back drought episodes created a shortage of water, dried up pastures and damaged forage, while severe cold resulted in high rates of premature death among herd animals. These climatic events thus had devastating economic and social consequences.

scholarly journals Dynamics for El Niño-La Niña asymmetry constrain equatorial-Pacific warming pattern

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Michiya Hayashi ◽  
Fei-Fei Jin ◽  
Malte F. Stuecker
Keyword(s):  
El Niño ◽  
Climate Models ◽  
El Nino ◽  
Southern Oscillation ◽  
Equatorial Pacific ◽  
La Niña ◽  
Nonlinear Dynamical ◽  
La Nina ◽  
Warming Pattern ◽  
Enso Asymmetry

Abstract The El Niño-Southern Oscillation (ENSO) results from the instability of and also modulates the strength of the tropical-Pacific cold tongue. While climate models reproduce observed ENSO amplitude relatively well, the majority still simulates its asymmetry between warm (El Niño) and cold (La Niña) phases very poorly. The causes of this major deficiency and consequences thereof are so far not well understood. Analysing both reanalyses and climate models, we here show that simulated ENSO asymmetry is largely proportional to subsurface nonlinear dynamical heating (NDH) along the equatorial Pacific thermocline. Most climate models suffer from too-weak NDH and too-weak linear dynamical ocean-atmosphere coupling. Nevertheless, a sizeable subset (about 1/3) having relatively realistic NDH shows that El Niño-likeness of the equatorial-Pacific warming pattern is linearly related to ENSO amplitude change in response to greenhouse warming. Therefore, better simulating the dynamics of ENSO asymmetry potentially reduces uncertainty in future projections.

scholarly journals Seasonal Modulations of El Niño–Related Atmospheric Variability: Indo–Western Pacific Ocean Feedback

2017 ◽  
Vol 30 (9) ◽  
pp. 3461-3472 ◽  
Author(s):  
Shang-Ping Xie ◽  
Zhen-Qiang Zhou
Keyword(s):  
Pacific Ocean ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
North Indian Ocean ◽  
Equatorial Pacific ◽  
Western Pacific ◽  
Northwest Pacific ◽  
Western Pacific Ocean ◽  
Combination Mode

The spatial structure of atmospheric anomalies associated with El Niño–Southern Oscillation varies with season because of the seasonal variations in sea surface temperature (SST) anomaly pattern and in the climatological basic state. The latter effect is demonstrated using an atmospheric model forced with a time-invariant pattern of El Niño warming over the equatorial Pacific. The seasonal modulation is most pronounced over the north Indian Ocean to northwest Pacific where the monsoonal winds vary from northeasterly in winter to southwesterly in summer. Specifically, the constant El Niño run captures the abrupt transition from a summer cyclonic to winter anticyclonic anomalous circulation over the northwest Pacific, in support of the combination mode idea that emphasizes nonlinear interactions of equatorial Pacific SST forcing and the climatological seasonal cycle. In post–El Niño summers when equatorial Pacific warming has dissipated, SST anomalies over the Indo–northwest Pacific Oceans dominate and anchor the coherent persisting anomalous anticyclonic circulation. A conceptual model is presented that incorporates the combination mode in the existing framework of regional Indo–western Pacific Ocean coupling.

No consistent ENSO response to volcanic forcing over the last millennium

Science ◽  
2020 ◽  
Vol 367 (6485) ◽  
pp. 1477-1481 ◽  
Author(s):  
Sylvia G. Dee ◽  
Kim M. Cobb ◽  
Julien Emile-Geay ◽  
Toby R. Ault ◽  
R. Lawrence Edwards ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Explosive Volcanism ◽  
Forced Response ◽  
Last Millennium ◽  
Superposed Epoch Analysis ◽  
Volcanic Forcing

The El Niño–Southern Oscillation (ENSO) shapes global climate patterns yet its sensitivity to external climate forcing remains uncertain. Modeling studies suggest that ENSO is sensitive to sulfate aerosol forcing associated with explosive volcanism but observational support for this effect remains ambiguous. Here, we used absolutely dated fossil corals from the central tropical Pacific to gauge ENSO’s response to large volcanic eruptions of the last millennium. Superposed epoch analysis reveals a weak tendency for an El Niño–like response in the year after an eruption, but this response is not statistically significant, nor does it appear after the outsized 1257 Samalas eruption. Our results suggest that those models showing a strong ENSO response to volcanic forcing may overestimate the size of the forced response relative to natural ENSO variability.

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