El Niño event of 1982-83 coincided with a drought that may have been the worst for 100 years. The 1982 winter rains (June - September) failed over the south-eastern grain and pasture areas of Australia. In northern New South Wales and southern Queensland, the summer rains (December 1982 - February 1983) also failed.
The American Heritage dictionary defines an anomaly as a deviation from the normal order and as something unusual or irregular. El Niño is an anomaly in terms of changes in sea surface temperatures and in sea level pressure. The 1982-83 El Niño can, therefore, be described as an anomalous anomaly. In addition to being unusual, it is considered by the scientific community to be the most extreme this century.
The sea surface temperatures associated with this El Niño were way above normal in the central and eastern equatorial Pacific (reaching 4 degree Celsius or more above normal in some areas). Those concerned about natural disasters and their socioeconomic impacts also considered it to have been a very extreme event, because of numerous destructive climate anomalies that occurred around the world at the time. In the wake of this particular El Niño event, many world leaders, the public, and the media, for the first time, were forced to pay more consistent attention to this phenomenon.
In 1982, several months prior to the onset of the 1982-83 El Niño, some researchers published an article on what they considered the "typical" El Niño. The canonical El Nino, as they called it, was in fact a composite of the features of several El Niño events that took place from the early 1950s to the late 1970s. Until then, it appeared that El Niño events had generally followed a similar pattern of growth and development from onset to decay. In less than a year, however, that notion was challenged with the occurrence of an unexpected out of phase onset of the 1982-83 event. According to Harrison and Cane,
"The warm event in the Pacific in 1982-83 was unusual in many respects. Rather than exhibiting surface warming first along the northeast coast of South America in the spring, sea surface temperatures first significantly exceeded climatological values along the equator in the eastern central Pacific during late summer."
(Harrison and Cane, 1984, p.21)
In addition, Rasmusson and Arkin (1985), in reviewing what had happened in 1982-83, wrote that the timing of the warming of water in the central Pacific was typical and that the warming along the Peruvian coast followed instead of preceded that warming. In any event, the coastal warming occurred at the normal time of the year.
The 1982-83 El Niño differed in both timing and location from the set of post-World War II events used to compile the characteristics of a "typical" event. For example, anomalously warm sea surface temperatures appeared first in the central Pacific instead of off the coast of Peru. The warm sea surface temperatures moved eastward toward the South American coast, instead of first appearing along the coast and then moving in a westward direction away from it. It emerged later in the year (between June and August) than the expected typical El Niño. The winds along the Peruvian coast did not weaken as expected when the El Niño began, even though a weakening of the westward flowing winds was considered to be a necessary, although not sufficient, condition to spark El Niño's onset.
澳洲代写作业 El Nino In The Galapagos Biology Essay
