What is the current Indian Ocean Dipole?
The Indian Ocean Dipole (IOD) is currently neutral. The latest IOD index value for the week ending 8 May 2022 was +0.13 °C.
How is Indian Ocean Dipole calculated?
The index is calculated as the monthly difference between the western (10°S-10°N, 50°-70°E) and eastern Indian Ocean (10°S-0°, 90°-108°E) sea surface temperature departures from average.
How often does the Indian Ocean Dipole occur?
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.
What causes a positive Indian Ocean Dipole?
Positive event: warmer sea surface temperatures in the western Indian Ocean relative to the east. easterly wind anomalies across the Indian Ocean and less cloudiness to Australia’s northwest. less rainfall over southern Australia and the Top End.
Is it an El Niño year 2020?
The 2020-2021 La Niña event has passed its peak, but impacts on temperatures, precipitation and storm patterns continue, according to a new update from the World Meteorological Organization (WMO).
What is the SOI index?
The Southern Oscillation Index (SOI) tracks the atmospheric part of the El Niño–La Niña climate pattern by comparing surface air pressure anomalies at Darwin, Australia, to pressure anomalies at Tahiti. The anomalies—departures from average conditions—indicate the strength of the Walker Circulation.
What is the ENSO 3.4 index?
The NINO3. 4 index is defined as the average of SST anomalies over the region 5°N – 5°S and 170° – 120°W. NCC classifies the NINO3. 4 temperature anomaly as “warm” if it exceeds 0.8°C, which is about one standard deviation above average.
What is the Indian Ocean Dipole 2021?
The Indian Ocean Dipole (IOD) is an irregular oscillation of sea surface temperatures and related atmospheric circulation in the Indian Ocean (Fig. 1). The IOD has positive and negative phases, which are defined by opposing sea surface temperature anomalies in the western and eastern tropical Indian Ocean (Fig. 2).
How long will Indian Ocean Dipole last?
Indian Ocean Dipole The IOD has three phases: neutral, positive and negative. Events usually start around May or June, peak between August and October and then rapidly decay when the monsoon arrives in the southern hemisphere around the end of spring.
How does Indian Ocean Dipole affect weather?
Positive IODs are associated with an increased chance for dry weather in southern and southeast Australia. The devastating Black Summer bushfires in 2019–20 were linked to an extreme positive IOD, as well as human-caused climate change which exacerbated these conditions.
How does climate change affect the Indian Ocean Dipole?
One scientist says changes in the Indian Ocean Dipole’s behaviour is increasing the risk of more droughts for Australia. Indian Ocean Dipole events have become stronger and more frequent since the 1960s.