What is Indian Ocean Dipole (IOD)?

June 4, 2015 4:52 PM |

IOD and MonsoonThe Indian Ocean Dipole (IOD) is defined by the difference in the sea surface temperature between the two equatorial areas of the Indian Ocean – a western pole near the Arabian Sea (in western Indian Ocean) and an eastern pole closer to the Bay of Bengal (in eastern Indian Ocean). The IOD affects the climate of Southeast Asia, Australia and other countries that surround the Indian Ocean Basin. The Indian Monsoon is invariably influenced by the IOD.

IOD is simply the periodic oscillation of sea surface temperatures, from ‘positive’ to ‘neutral’ and then ‘negative’ phases. If the sea surface temperature of the western end rises above normal (0.4°C) and becomes warmer than the eastern end, it leads to a positive IOD. This condition is favourable for the Indian Monsoon as it causes a kind of barrier in the eastern Indian Ocean and all the southwesterly winds blow towards the Indian sub-continent.

Accordingly, the waters in the eastern Indian Ocean cools down, which tends to cause droughts in adjacent land areas of Indonesia and Australia.

Conversely, during a negative IOD period the waters of the tropical eastern Indian Ocean is warmer than water in the tropical western Indian Ocean. This results in increased rainfall over parts of southern Australia.

Difference between El Nino and IOD

The Indian Ocean Dipole (IOD) and the El Nino are independent climatic phenomena but often co-occur. Both IOD and El Nino result in change of global wind patterns. To know about the change of wind patterns, click here.

However the cycle of IOD is shorter, while El Nino condition could last for even two years. IOD commences in the month of May and end with the withdrawal of Southwest Monsoon in the Indian sub-continent.

To know about the Impact of El Nino on Indian Monsoon, click here.

For latest updates on Monsoon 2015, click here.

Image credit - The Hindu

 

 





For accurate weather forecast and updates, download Skymet Weather (Android App | iOS App) App.

Weather Forecast

Other Latest Stories



Weather on Twitter
#DelhiPollution has become hazardous and will continue to get worse with no relief until Nov 15. Stay safe folks.… t.co/Ri9iafVPkx
Tuesday, November 12 11:38Reply
According to Skymet #Weather, we can expect #rains to commence over #Chennai by November 14 and would most likely t… t.co/SC9rItqFlv
Tuesday, November 12 11:30Reply
RT @SkymetAQI: With PM 2.5 over 600, Faridabad Sector 49 has HAZARDOUS air quality. Track #AirQuality and #AirPollution of your location, d…
Tuesday, November 12 11:18Reply
RT @SkymetAQI: With PM 2.5 touching 600, Pandara Road India Gate has HAZARDOUS air quality. Track #AirQuality and #AirPollution of your loc…
Tuesday, November 12 11:18Reply
RT @SkymetAQI: With PM 2.5 touching 600, New Delhi Railway Station has HAZARDOUS air quality. Track #AirQuality and #AirPollution of your l…
Tuesday, November 12 11:18Reply
RT @SkymetAQI: With PM 2.5 crossing 400 mark all over, Rohini has HAZARDOUS air quality. Track #AirQuality and #AirPollution of your locati…
Tuesday, November 12 11:18Reply
#Nakri will weaken further as it travels across #Laos, #SouthChinaSea and #Thailand. As per weathermen, we can expe… t.co/6NuGkqWtYB
Tuesday, November 12 11:15Reply
Remnants of #CycloneNakri will help in reviving #NortheastMonsoon, which has been subdued for the last few days. Du… t.co/e1mCkRt5CG
Tuesday, November 12 11:00Reply
Prolonged dry spell over #Chennai is finally coming to an end very soon. The much awaited rainy spells can be attri… t.co/88PnzR2dPj
Tuesday, November 12 10:45Reply
जम्मू कश्मीर और लद्दाख में कुछ स्थानों पर हल्की बारिश या बर्फबारी के आसार। गुजरात, राजस्थान, केरल, कर्नाटक और तमिल… t.co/mi07klCFZr
Tuesday, November 12 10:30Reply


latest news

Skymet weather

Download the Skymet App

Our app is available for download so give it a try