Science Source

Large anomalies in lower stratospheric water vapour and ice during the 2015-2016 El Niño

States that the coldest tropical tropopause temperature regulates the amount of water vapour entering the stratosphere by controlling the amount of dehydration in the rising air
Shows that tropical convective cloud ice and associated cirrus sublimating at unusually high altitudes might also have a role in stratospheric hydration
Notes that the 2015–2016 El Niño produced decadal record water vapour amounts in the tropical Western Pacific, coincident with warm tropopause temperature anomalies
States that in the Central Pacific, convective cloud ice was observed 2 km above the anomalously cold tropopause
Finds that trajectory-based dehydration model based on two reanalysis temperature and wind fields can account for only about 0.5–0.6 ppmv of the ~0.9 ppmv tropical lower stratospheric moistening observed during this event
Finding suggests that unresolved convective dynamics and/or associated sublimation of lofted ice particles also contributed to lower stratospheric moistening
Observations suggest that convective moistening could contribute to future climate change-induced stratospheric water vapour increases