“This is the ninth special monsoon article of 2011 and it will follow the second last monsoon article of the current year”
La-Nina brings flooding to India during monsoon
During the middle of this year, many reports from the United States and Japan started circulating the world web that suggested that Indian monsoon-friendly La-Nina may return during the end of this year. There is no doubt that the scientists at the Regional Institute for global Change (RIGC) based in Tokyo had predicted the La-Nina conditions but the US National Weather Service were the first to suggest that La-Nina could return this year as well. Last year, La-Nina brought death and destruction to almost every part of the world from hurricanes to drought, the whole world was left shocked by the destruction in every part of the globe. La-Nina increased the hurricane activity in North Atlantic Ocean while the opposite in Pacific Ocean, severe flooding in Pakistan and North-west India and the list goes on and on.
La-Nina is an Indian monsoon-friendly, though without direct cause-effect relationship unlike its brother El-Nino which brought severe drought in India and Pakistan since the great drought of early 21st century and again in 2009. For the people of Indian Sub-continent La-Nina is regarded as a phenomena that brings rainfall while El-Nino only brings high pressures. In the other part of the world it is the complete opposite as climatic conditions vary from place to place just like human thinking.
El-Nino/La-Nina – South Oscillation
Both these phenomena are famous for having irregularity, it is thought that they happen every 5 year respectively but this study is not supported by other scientist. Overall there are two types of this phenomena;
- El-Nino is a spanish word which means boy, it may also refer to a Christ child, because of the periodic warming in the Pacific near South America that happens around Christmas. It causes extreme weather (such as floods and droughts) in many regions of the world. It causes drought in India, Pakistan, Bangladesh and many countries of the world, while it causes wet conditions and floods in other part of the world. It has a deep effect on the Indian monsoon. It forms due to the warming of Pacific Ocean thus the number of typhoons are increased in Pacific ocean while Atlantic ocean usually becomes calm due to intense wind shear. El-Nino is also said to increase malaria disease in India.
- La-Nina is a spanish word which means girl. La-Nina is the complete opposite of El-Nino. It causes wet conditions and floods in the Sub-continent while drought and dry weather over other parts of the world. It happens due to the cooling of Pacific ocean.
La-Nina returning this year again?
It is only the Americans and Japanese that point finger towards La-Nina. Americans are less confident but the Japanese were much more confident.
Japanese Outlook for La-Nina
Japanese scientists have already said that La Nina conditions may already be happening. Scientists at the Regional Institute for global Change (RIGC) based in Tokyo have been saying this for quite some time. Dr Jing-Jia Luo, Senior Scientist at RIGC, said that
“The La Nina condition is currently on the way back. This condition is forecast to persist until early next year.”
La Nina would bring cool to wet conditions over southern Africa, Australia, and Brazil during the southern hemisphere summer.
Americans Outlook for La-Nina
Few days back the US National Weather Services too had officially changed its outlook for the Pacific into a “La Nina watch”.
The National Weather Service has forecasted that there is 50% chance of La-Nina returning while 50% chance of no La-Nina at all.
Nielsen Gammon working at the National Weather Service had this to say;
“It’s also important to remember the large computer models used by the weather service are predicting a weak to moderate. Not nearly as strong as the forecasts were saying at this time last year.”
All the super computers used the U.S do not show any sign of cooling of the Pacific. Last year’s strong La-Nina caused severe drought in the state of Texas in the United States, for the Americans it’s a bad news.
La-Nina coming with a positive Indian Ocean Dipole (IOD)?
Pakistan Weather Portal (PWP) did mention that there has been some news about the returning of La-Nina with +IOD as of now that news stays in contact but only the Japanese scientist agree on that. Like ENSO, there are two types of Indian Ocean Dipoloe. IOD is an irregular phenomenon in which the western equatorial of the Indian Ocean becomes warmer while the eastern equatorial cooler.It affects the Sub continent, Australia, Indonesia and many other surrounding countries. There are two phases of Indian Ocean Dipole; 1. Positive IOD 2. Negative IOD
- Positive Indian Ocean Dipole (+IOD) causes sea temperatures to rise in the western Indian Ocean with heavy precipitation in Sub-continent while it makes the sea temperatures cooler in the eastern Indian Ocean with drought or very little to no precipitation in Australia and Indonesia.
- Negative Indian Ocean Dipole (-IOD) causes cooler sea temperatures in western Indian Ocean with no rainfall in the Sub-continent while eastern Indian Ocean becomes warmer with heavy precipitation.
But if positive Indian Ocean Dipole (IOD) happens it is likely to be a weak one. It is forecasted by those same Japanese that it may form in next few months.
Whats for monsoon then?
There has been no strong weather system this year that could have the potential to bring widespread heavy rainfall to any part of the Sub-continent except for the deep depression BOB 02 during June in India and a strong low pressure during mid-August in Pakistan. Overall if we see the timings of the “expected” formation of La-Nina and weak +IOD, it shows that monsoon might be unaffected because the peak intensity of monsoon is from late July till early late August and after that monsoon withdraws during the second week of September. The Japanese and Americans have said that La-Nina (weak to moderate) may return after August (during Autumn), so it seems that the La-Nina will miss out the south-west monsoon if it forms. But the north-east monsoon might be affected by La-Nina which does not happen in Pakistan, but if La-Nina happens.
Monsoon Special articles for 2011
You can read special monsoon article of current year (2011) by Pakistan Weather Portal (PWP), here;
- Monsoon 2011 and Cyclones – Sub-continent’s coastal threat?-Part 3
- Monsoon and its Dangers – How many people will die this year?- Part4
- When will Monsoon start over Pakistan? – In Detail!-Part 5
- Monsoon 2011: Backlash of the floods? – History of Pakistan floods in Detail-Part 6
- Monsoon rain of July 28, 2010 – Dark day, but more was ahead!-Part 7
- Much awaited monsoon showers lashes Karachi!-Part 8
- Little girl may return for Monsoon: La-Nina episode!-Part 9
- Heavy downpour in Karachi!-Part 10