From UPSC perspective, the following things are important :
Prelims level : Northern Limit of Monsoon (NLM)
Mains level : Indian Monsoon
The Northern Limit of Monsoon (NLM) continues to pass through Diu, Surat, Nandurbar, Bhopal, Nowgong, Hamirpur, Barabanki, Bareilly, Saharanpur, Ambala & Amritsar.
Try this question from CS Mains 2017:
Q.What characteristics can be assigned to monsoon climate that succeeds in feeding more than 50 percent of the won population residing in Monsoon Asia?
What is the Northern Limit of Monsoon?
- NLM, is the northernmost boundary of India up to which monsoon rains have advanced on any given day.
- So, it is a way of tracking the progress of monsoon clouds as they move over India’s landmass.
- The India Meteorological Department (IMD) adds that the monsoon “advances northwards, usually in surges, and covers the entire country around July 15″.
What are the Eastern and Western Arms?
- It is the mountains of southern India that split the south-western winds, giving the Indian monsoon its ‘two arms.
- The western arm of the monsoon is deflected northwards, by the Western Ghats, to (Mumbai) and then on to Pakistan.
- The eastern arm travels up through the Bay of Bengal to (Kolkata) and Assam and is deflected north-westwards by the Himalayas.