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3254686 
Journal Article 
Convective transport of water vapor into the lower stratosphere observed during double-tropopause events 
Homeyer, CR; Pan, LL; Dorsi, SW; Avallone, LM; Weinheimer, AJ; O'Brien, AS; Digangi, JP; Zondlo, MA; Ryerson, TB; Diskin, GS; Campos, TL 
2014 
Yes 
Journal of Geophysical Research: Atmospheres
ISSN: 2169-897X
EISSN: 2169-8996 
119 
18 
10941-10958 
WOS:000344052800021 
We present in situ observations of convectively injected
water vapor in the lower stratosphere from instruments aboard two aircraft operated during the
Deep Convective Clouds and Chemistry experiment. Water vapor mixing ratios in the injected air
are observed to be 60-225 ppmv at altitudes 1-2 km above the tropopause (350-370 K potential
temperature), well above observed background mixing ratios of 5-10 ppmv in the lower
stratosphere. Radar observations of the responsible convective systems show deep overshooting at
altitudes up to 4 km above the lapse rate tropopause and above the flight ceilings of the
aircraft. Backward trajectories from the in situ observations show that convectively injected
water vapor is observed from three distinct types of systems: isolated convection, a convective
line, and a leading line-trailing stratiform mesoscale convective system. Significant transport
of additional tropospheric or boundary layer trace gases is observed only for the leading line-
trailing stratiform case. In addition, all observations of convective injection are found to
occur within large-scale double-tropopause events from poleward Rossby wave breaking. Based on
this relationship, we present a hypothesis on the role of the large-scale lower stratosphere
during convective overshooting. In particular, the reduced lower stratosphere stability
associated with double-tropopause environments may facilitate deeper levels of overshooting and
convective injection.