Transport is around the anticyclone and moist air is quasi-confined to the region of the anticyclone. In the final stage the synoptic-scale disturbance often splits the monsoon anticyclone into two parts and the moisture supply stops locally. It also occurs at other longitudes, mainly in association with extratropical cyclones that develop along the North Pacific storm track. Some of the moisture for these events is supplied by transport of moist air from the monsoon anticyclone along upper tropospheric jet streams that lie near the dynamical tropopause. Hence, the role of the Asian monsoon in moistening the upper troposphere and lower stratosphere is not just a local one.
Red colours indicate stratospheric air.
Red and brown colours mark the moistest air. The moisture input into the upper troposphere and lower stratosphere experiences a strong seasonality. The largest values occur in association with the Asian summer monsoon. The seasonal shift of moisture input follows the migration of the monsoon. Moistening also occurs due to the Mexican monsoon, but moisture values are much lower there.