MISO: Monsoon Intraseasonal Oscillation
Quite an underreported important dynamic many forget to bring in during monsoon news when we talk about how monsoon is influenced along with MJO, Somalian jet, Tropical Easterly jet(TEJ). In this article, we venture out on knowing what is MISO and how it actually influences our South- West monsoon.
So what is actually MISO? Monsoon Intraseasonal Oscillation (MISO) is a progress of monsoon currents in the tropical region especially Asia. Also known as Boreal Summer Intra-Seasonal Oscillation (BSISO) has northward as well as eastward movement. Along with MJO, this also acts as an energy enhancer for monsoon to reach all over India starting from Southern parts of the country and slowly climbing upwards latitude to help monsoon reach the country in a progressive way. This oscillation is generally active during May- September primarily acts as monsoon enricher.
(PICTURE 1)
From the above picture, we can clearly see how MISO progresses across the country starting with Southern parts of India and gradually covers each part of the nation. MISO is controlled by East Arabian Sea and West Bay of Bengal branches. Now that we have seen what MISO actually is, we should know the differences between MISO and MJO. MISO which is a northward and eastward propagating wave travels across the country from South eventually moves above in latitude. MJO, uniformly eastward propagating wave travels the world across the equator every 30 days. Unlike MISO which climbs up latitude, MJO moves only around the equator however both influence South- West monsoon in their own unique ways. For visualization of classification between MISO and MJO refer the below image.
(PICTURE 2)
MJO which can be quite easily predicted thanks to its uniform travelling propagation across the world, MISO is much more complex. It combines air-sea coupling along with inter- tropical convergence zone (ITCZ) movement thus it is not easy to predict MISO phases for prediction of monsoon. MISO plays a very crucial role in movement of seasonal currents (monsoon swayer) which along with position of monsoon trough decides active and break monsoon phases. he way that the MISO affects rainfall and drought patterns is important to the economies and livelihoods of the people that live in South and Southeast Asia. MISO represent a very large signal and hence potentially predictable.
MISO influence on monsoon:
Miso and its effect on our monsoon, the miso is the key factor that helps our monsoon, this northward propagation of miso helps activating monsoon in various parts of country this shifts the convection from our basin to west pacify this event happens every 10-15 days the warm sst anomalies indicate active monsoon, cold anomalies indicate break period thus it's movement helps in keeping the monsoon active over India (SSR)
The Monsoon Intraseasonal Oscillation (MISO) is a process that occurs several times each year from May-October in the atmosphere over the tropical Indian Ocean, the western tropical Pacific Ocean, and the surrounding land areas. MISO events alternate between periods of wetter-than-average and drier-than-average conditions, a cycle that lasts longer than typical weather systems do (1-2 weeks), but shorter than a season (90 days). The way that the MISO affects rainfall and drought patterns is important to the economies and livelihoods of the people that live in South and Southeast Asia.