Trends in Associated Atmospheric Parameters
Trends in the environmental parameters, namely SST, vertical wind shear (VWS), low-level vorticity at 850 hPa (VOR850) and mid-tropospheric humidity at 500 hPa (RH500) have been analysed for BOB and AS by Mohapatra et al. (2015) from the time series of area averaged seasonal and annual mean values of the parameters during the period 1951-2010. It has been shown that there is a significant increasing trend in the SST and a significant decreasing trend in the RH500 during all the three seasons (pre-monsoon, monsoon and post-monsoon seasons) over both BOB and AS. The vertical wind shear has decreased significantly over AS during the pre-monsoon season, over both BOB and AS during the monsoon season and over AS and southern parts of BOB during the post-monsoon season. It has increased over the northern parts of BOB. The low-level cyclonic vorticity has increased over the BOB during the pre-monsoon season and over northern parts of the BOB during the post-monsoon season in the recent decades.