Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 18, 4425-4437, 2018
https://doi.org/10.5194/acp-18-4425-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
03 Apr 2018
Effects of convective ice evaporation on interannual variability of tropical tropopause layer water vapor
Hao Ye, Andrew E. Dessler, and Wandi Yu Department of Atmospheric Sciences, Texas A&M University, College Station, TX, USA
Abstract. Water vapor interannual variability in the tropical tropopause layer (TTL) is investigated using satellite observations and model simulations. We break down the influences of the Brewer–Dobson circulation (BDC), the quasi-biennial oscillation (QBO), and the tropospheric temperature (ΔT) on TTL water vapor as a function of latitude and longitude using a two-dimensional multivariate linear regression. This allows us to examine the spatial distribution of the impact of each process on TTL water vapor. In agreement with expectations, we find that the impacts from the BDC and QBO act on TTL water vapor by changing TTL temperature. For ΔT, we find that TTL temperatures alone cannot explain the influence. We hypothesize a moistening role for the evaporation of convective ice from increased deep convection as the troposphere warms. Tests using a chemistry–climate model, the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM), support this hypothesis.
Citation: Ye, H., Dessler, A. E., and Yu, W.: Effects of convective ice evaporation on interannual variability of tropical tropopause layer water vapor, Atmos. Chem. Phys., 18, 4425-4437, https://doi.org/10.5194/acp-18-4425-2018, 2018.
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Short summary
The deep convection in tropics can inject cloud ice into tropical tropopause layer (TTL), which moistens and increases water vapor there. We primarily study the spatial distribution of impacts from several physical processes on TTL water vapor from observations and trajectory model simulations. The analysis shows the potential moistening impact from evaporation of cloud ice on TTL water vapor. A chemistry–climate model is used to confirm the impact from evaporation of convective ice.
The deep convection in tropics can inject cloud ice into tropical tropopause layer (TTL), which...
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