TY  - JOUR
AU  - Jensen, E. J.
AU  - Pan, Laura L.
AU  - Honomichl, Shawn
AU  - Diskin, Glenn S.
AU  - Krämer, Martina
AU  - Spelten, Nicole
AU  - Günther, Gebhard
AU  - Hurst, Dale F.
AU  - Fujiwara, Masatomo
AU  - Vömel, Holger
AU  - Selkirk, Henry B.
AU  - Suzuki, Junko
AU  - Schwartz, Michael J.
AU  - Smith, Jessica B.
TI  - Assessment of Observational Evidence for Direct Convective Hydration of the Lower Stratosphere
JO  - Journal of geophysical research / D Atmospheres
VL  - 125
IS  - 15
SN  - 2169-8996
CY  - Hoboken, NJ
PB  - Wiley
M1  - FZJ-2020-03047
SP  - e2020JD032793
PY  - 2020
AB  - In situ and remote sensing observations of water vapor are analyzed to assess the evidence for direct convective hydration of the lower stratosphere. We have examined several hundred balloon‐borne and airborne in situ measurements of lower stratospheric humidity in the tropics and northern midlatitudes. We find that the tropical lower stratospheric H2O enhancements above the background occur quite infrequently, and the height of the enhancements is within about 1 km of the cold‐point tropopause. Following Schwartz et al. (2013, https://doi.org/10.1002/grl.50421), we examine the anomalously high (above 8 ppmv) water vapor mixing ratios retrieved by the Aura Microwave Limb Sounder (MLS) at 100‐ and 82‐hPa pressure levels, and we determine their vertical location relative to the local tropopause based on both Global Forecast System (GFS) operational analysis and the ERA5 reanalysis temperature data. We find that essentially all of the >8‐ppmv MLS water vapor measurements over the extratropical North American monsoon region are above the relatively low lapse‐rate tropopause in the region, and most are above the local cold‐point tropopause. Over the Asian monsoon region, most (80/90%) of the high H2O values occur below the relatively high‐altitude local lapse‐rate/cold‐point tropopause. Anomalously high MLS water vapor retrievals at 100 and 82 hPa almost never occur in the deep tropics. We show that this result is consistent with the in situ observations given the broad vertical averaging kernel of the MLS measurement. The available evidence suggests that direct hydration of the lower stratosphere is important over North America during the monsoon season but likely has limited impact in the tropics.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000562078700007
DO  - DOI:10.1029/2020JD032793
UR  - https://juser.fz-juelich.de/record/878794
ER  -