May 29, 2017
Large anomalies in lower stratospheric water vapour and ice during the 2015-2016 El Niño
by
,
Nature Geoscience
- 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