“This is the second article related to the monsoon season of 2012 and it will be followed by many more articles”
The word “monsoon” is derived from Arabic, Hindi and Urdu words of mawsim (موسم) meaning weather, there is also some indications the word is derived from Dutch word of monsun. The Englishmen used to use this word to define a seasonal prevailing wind in the region blowing from the south-west between May and September and bringing heavy rainfalls to British India.
How do Monsoon form?
Before the monsoon season, the land and oceans start to heat up with the consequence that the air over the land warms faster and reaches a higher temperature than the air over the ocean. The hot air over the land tends to rise, creating an area of low pressure. This creates a steady wind blowing toward the land, bringing the moist near-surface air over the oceans with it, thus monsoon season begins.
A monsoon is traditionally defined as a seasonal reversal of wind direction which is accompanied by changes in precipitation. In Asia, the monsoon season runs from May to September, when Southern Hemisphere winds shift direction and blow north and west across the Equator into Asia, bringing moisture from the oceans they pass over on the way.
Factors affecting this year’s monsoon season
The La-Nina which occur in Pacific Ocean have impact on monsoon. In 2010, La Nina was one of the positive factors to have caused good monsoon across the Indian Subcontinent . La-Nina (late 2011 -2012) re-emerged late in November after one of the strongest La-Nina (2010- early 2011) in the weather history. Following are the conditions which could affect monsoon 2012;
- El-Nino (later in the season)
Before the strong La-Nina pattern, El-Nino (2009 – 2010) was dominating the world that transitional period between El-Nino and La-Nina was on the fastest in recent years in 2010. It was actually because of La-Nina that India and Pakistan saw a good monsoon in 2010 and 2011. It is official now that the La-Nina that re-emerged in November has finally fizzled out after decaying rapidly and conditions are moving towatds a neutral phase.
Indian Monsoon 2012 – What could happen?
It may mean that monsoon 2012 would be near normal to below normal as a whole over the sub-continent but having said that there are always some isolated places that experiences above normal rainfall and this year it seems as if it would be West Bengal, Jharkhand, Assam, Utter Pradesh, Madya Pradesh and parts of Bangladesh. It is likely that monsoon rainfalls may develop rapidly during the onset of the season but as summer progresses further a decrease in the overall coverage of rainfall could occur. In August and September, are the two months in which decrease in the rainfall activity is expected.
The setback for the monsoon season of 2012 is that El-Nino might form during late July that has been observed to cause drought-like conditions across India and Pakistan. While the monsoon also faces another emerging threat that is the Indian Ocean Dipole. Unlike last year when there was a slim chance of +IOD, this year there is a chance of a -IOD that means that the pattern of monsoon would be disturbed. This will decide the fate of the monsoon this year.
Monsoon Special articles for 2012
You can read special monsoon article by Pakistan Weather Portal (PWP), here;
- Let it be La-Nina or maybe El-Nino? - Part I
- Monsoon 2012 – What will happen in Pakistan? - Part II
- Pollute the Arabian sea for stronger Hurricanes before the Monsoon season! - Part III
- Total collapse of Monsoon expected in July? - Part IV
- Monsoon advancing into Pakistan: All stages set! - Part V
- El-Nino comeback: Monsoon collapses, Pakistan going into drought! - Part VI
TO BE CONTINUED……