This study explores the variability of the Asian summer monsoon anticyclone (ASMA) spatial variability and trends using long-term observational and reanalysis data sets. The decadal variability of the anticyclone is very large at the edges compared with the core region. We propose that the transport process over the Tibetan Plateau and the Indian region is significant in active monsoon, strong monsoon and strong La Niña years. Thus, different phases of the monsoon are important in UTLS analyses.

The Asian Summer Monsoon Anticyclone (ASMA) plays an important role in confining the trace gases and aerosols for a longer period. This study explores the variability of tropopause parameters, trace gases and aerosols and its relation with ENSO and QBO in ASMA. Further, the influence of the Indian summer monsoon activity on the ASMA trace gases and aerosols is studied with respect to active and break spells of monsoon, strong and weak monsoon years and strong La Niña, El Niño years.

The regional extreme mean temperature values increase moderately compared to the historical values at about 1.82 and 2.92 °C in the 50-year period under RCP6.0 and 8.5 scenarios. Comparing the 10- to 50-year return periods, the warm extremes increase at about ~ 3 °C especially over the eastern and western regions of India. The effect of increasing radiative forcing under higher concentration pathways is larger on cold temperatures compared to warm extreme temperatures.