Environmental investigations scientists warn of critical gaps in australias climate science capability. The heat transfer controls weather over both land and sea. Originally described in 1893 as corriente del nino1 a warm regional ocean current. Such events are a consequence of strong and extensive interactions between the ocean and atmosphere. The name enso is a reminder that close interaction between the atmosphere and ocean is an essential part of the. The southern oscillation index soi is a standardized index based on the observed sea level pressure differences between tahiti and darwin, australia.
Southern oscillation index soi teleconnections national. The southern oscillation is the accompanying atmospheric component. They are associated with widespread changes in the climate system that last several months, and can lead to significant socioeconomic impacts affecting infrastructure, agriculture. This type of climatology is fundamental because it teaches. This region of the ocean is normally colder than its equatorial location would suggest, mainly due to the influence of northeasterly trade winds, a cold ocean current flowing up the coast of chile, and to the. Observations of the tropical pacific ocean during a normal year the national oceanographic and atmospheric administration noaa maintains several laboratories.
It is a large scale oceanatmosphere climate interaction that originates in the pacific ocean but spreads across the world. The southern oscillation index soi is a standardized index based on the observed. Climate prediction center southern oscillation index links. Diminished fisheries off south america, drought in western pacific, increased precipitation in southwestern north america, fewer atlantic hurricanes. The future of the worlds climate second edition, 2012. As the name suggests, enso consists of two components. Ensoneutral is favored for the northern hemisphere summer 2020 60% chance. The various cold and warm patches of ocean water act to cool or heat the atmosphere, influencing global climate patterns.
Climate prediction center southern oscillation index. Since enso is one of the most prominent sources of interannual variations in regional patterns of precipitation and temperature, any uncertainty in how it will change implies a corresponding uncertainty in certain regional patterns of climate change. It occurs every 27 years, typically lasting 618 months. Abstract a 116yrsouthern oscillation index record was used in conjunction with environmental data and. Takahashi and mosqueratvasquezinstituto geofisico del peru. This volume provides a brief history of the subject, summarizes the oceanographic and meteorological observations and theories, and discusses the recent. It is a major contributor to australias climate, and affects australias exclusive economic zone eez marine waters to differing degrees around the coast.
It can be explained neither in strictly oceanographic nor strictly meteorological terms. Recent studies have suggested that the enso is a significant source of tidal variability in. The soi is one measure of the largescale fluctuations in air pressure occurring between the western and eastern tropical pacific i. Again, fill in the data tables and use those data to make a plot of the. For example, when the pressure is low in the south pacific high pressure cell and high over indonesia and australia, the pacific trade winds weaken, upwelling of cool water on the pacific. The southern oscillation index soi, which measures enso, is calculated from the difference between the standardised surface air pressures at tahiti and darwin. Enso has a strong and very significant effect on the intensity of the southward flowing leeuwin current, and. Observations of the tropical pacific ocean during a normal year the national oceanographic and atmospheric administration noaa maintains several laboratories around the country for specialized atmospheric and oceanic research.
We have already seen an example of a natural mode of climate variability above in the amo. The pattern can shift back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, precipitation, and winds. National weather service weather forecast office bismarck, nd. The southern oscillation is a seesaw of atmospheric mass pressure between the pacific and indo australian areas. It is a large scale ocean atmosphere climate interaction that originates in the pacific ocean but spreads across the world. Enso represents a coupled mode of the ocean and atmosphere, which is to say that the atmosphere influences the ocean. Enso is a coupled oscillation in the tropical pacific ocean and atmosphere, characterized in the ocean by a shift in the position of the very warm water that makes up the tropical western pacific warm pool. It can be explained in neither strictly oceanographic nor strictly meteorological terms.
1182 775 1433 1535 543 1290 46 452 1315 1535 17 1221 210 929 598 68 802 503 339 591 1435 978 181 1218 370 444 1446 674 1171 602 1453 1162