Why Southwest Monsoon Of 2020 Going To Be Normal?
The monsoon is active during the month of July, August and September. This year Pacific sea condition is neutral during the coming monsoon season as per international models. Rather it is inclined towards La-Nina condition particularly during July, August and September. This is the first link with Indian Summer Monsoon which is to be observed. Below are some of the factors which might influence the activity of monsoon all over India in the year 2020.
La-Nina
La-Nina condition is connected to good Indian Summer Monsoon, so this year the Pacific sea is favorable. Overall ENSO will be neutral but models are suggesting weak La Nina condition can develop in late 2020.
Indian Ocean Dipole (IOD) This Year
Indian Ocean Dipole plays a major role in the activity of monsoon. A positive IOD (warm red area in Arabian sea) is favourable for good monsoon over India with less rain over North Australia, Indonesia and Malaysia.
For negative IOD (cold blue area in the Arabian sea) it’s less rain over the Indian region and more in the Australian region.
During the months of July, August and September in 2020, the value of the IOD index is reaching below – 0.8 (minus 0.8) as per the models. It means Negative IOD is unfavorable for Monsoon.
Last year El Nino persisted over the Pacific sea but due to strong positive IOD, India received good monsoon rain. Monsoon started in the month of June with a lazy phase. It continued until late July. Though June month was deficient by 30 percent later it picked up and received the highest (130% of normal) cumulative rainfall during August, September.
Mascarene High & MJO
Apart from these three conditions, some more factors are there affecting the monsoon. These are a high-pressure area in Southern Hemisphere which is Mascarene High and Median Julian Oscillation.
The strength of monsoon depends on the strength of cross-equatorial flow curving from Somalia islands towards the Indian region. The source of this flow is the high-pressure area located between 25°S-35°S and 40°E-90°E near the Mascarene Islands in the southern Indian Ocean. This powerhouse high pressure is called Mascarene High. A stronger high pressure will produce stronger winds or monsoon currents.
image source: downtoearth.org
Conclusion of Monsoon over India:
On the basis of the present state of various parameters studied, Southwest Monsoon rainfall over India as the whole country will be normal. The southern parts of India will get below normal rainfall however central and India i.e. Vidarbha, Telangana, Madhya Pradesh and Uttar Pradesh will get above normal rainfall.
This is a preliminary interpretation as per the data available. As time progresses, more parameters will be studied and discussed to get a clear picture of Monsoon 2020. Welcome to the quest …….!
