3.3 Effect of Climatic Drivers in Generating Atmospheric River
The Onset of the Monsoon in the Indian South Continent initiates in May which concentrates in the region during June. To differentiate the monsoon Onset and the formation of AR, the influence of Low-Level Jet (LLJ) in the formation of AR has been investigated. The Wind Speed and Geopotential Height at 500 hPa level have been plotted for 15 June 12 AM timeframe for 2021 and 2022 illustrated in Figure 6. During the Onset of the Monsoon, strong winds from the Indian Ocean move towards the Bay of Bengal during mid-June which supplies the moisture in India and Bangladesh as depicted in Figure 6 (a) for 2021 when AR was not formed. In contrast, a conspicuous high-speed wind jet is observed in 2022 moving across the Northern region of India towards the Pacific Ocean covering Bangladesh and surrounding countries illustrated in Figure 6(b). This jet allows the moisture to move in a short corridor with a high velocity that subsequently created an Atmospheric River on 15 June 2022.