CloudCb Escreveu:De que maneira esse gradiente no Índico nos afeta?
Se foi a primeira vez que observou isso meus parabéns.
Você está vendo uma clássica configuração de IOD positiva.
Alguns trechos introdutórios para IOD via wiki (apenas introdução)
Water temperatures around the Mentawai Islands dropped about 4° Celsius during the height of a positive phase of the Indian Ocean Dipole in November 1997. During these events unusually strong winds from the east push warm surface water towards Africa, allowing cold water to upwell along the Sumatran coast. In this image blue areas are colder than normal, while red areas are warmer than normal.
The IOD involves an aperiodic oscillation of sea-surface temperatures, between "positive", "neutral" and "negative" phases. A positive phase sees greater-than-average sea-surface temperatures and greater precipitation in the western Indian Ocean region, with a corresponding cooling of waters in the eastern Indian Ocean—which tends to cause droughts in adjacent land areas of Indonesia and Australia. The negative phase of the IOD brings about the opposite conditions, with warmer water and greater precipitation in the eastern Indian Ocean, and cooler and drier conditions in the west.
The IOD also affects the strength of monsoons over the Indian subcontinent. A significant positive IOD occurred in 1997–98, with another in 2006. The IOD is one aspect of the general cycle of global climate, interacting with similar phenomena like the El Niño-Southern Oscillation (ENSO) in the Pacific Ocean.
The IOD phenomenon was first identified by climate researchers in 1999.
An average of four each positive-negative IOD events occur during each 30-year period with each event lasting around six months. However, there have been 12 positive IODs since 1980 and no negative events from 1992 until a strong negative event in late 2010. The occurrence of consecutive positive IOD events is extremely rare with only two such events recorded, 1913–1914 and the three consecutive events from 2006 to 2008 which preceded the Black Saturday bushfires. Modelling suggests that consecutive positive events could be expected to occur twice over a 1,000-year period. The positive IOD in 2007 evolved together with La Niña, which is a very rare phenomenon that has happened only once in the available historical records (in 1967). A strong negative IOD developed in October 2010, which, coupled with a strong and concurrent La Niña, caused the 2010–2011 Queensland floods and the 2011 Victorian floods.
In 2008, Nerilie Abram used coral records from the eastern and western Indian Ocean to construct a coral Dipole Mode Index extending back to 1846 AD. This extended perspective on IOD behaviour suggested that positive IOD events increased in strength and frequency during the 20th century.