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@ARTICLE{Konopka:910157,
author = {Konopka, Paul and Tao, Mengchu and von Hobe, Marc and
Hoffmann, Lars and Kloss, Corinna and Ravegnani, Fabrizio
and Volk, C. Michael and Lauther, Valentin and Zahn, Andreas
and Hoor, Peter and Ploeger, Felix},
title = {{T}ropospheric transport and unresolved convection:
numerical experiments with {CL}a{MS} 2.0/{MESS}y},
journal = {Geoscientific model development},
volume = {15},
number = {19},
issn = {1991-959X},
address = {Katlenburg-Lindau},
publisher = {Copernicus},
reportid = {FZJ-2022-03644},
pages = {7471 - 7487},
year = {2022},
abstract = {Pure Lagrangian, i.e., trajectory-based transport models,
take into account only the resolved advective part of
transport. That means neither mixing processes between the
air parcels (APs) nor unresolved subgrid-scale advective
processes like convection are included. The Chemical
Lagrangian Model of the Stratosphere (CLaMS 1.0) extends
this approach by including mixing between the Lagrangian APs
parameterizing the small-scale isentropic mixing. To improve
model representation of the upper troposphere and lower
stratosphere (UTLS), this approach was extended by taking
into account parameterization of tropospheric mixing and
unresolved convection in the recently published CLaMS 2.0
version. All three transport modes, i.e., isentropic and
tropospheric mixing and the unresolved convection can be
adjusted and optimized within the model. Here, we
investigate the sensitivity of the model representation of
tracers in the UTLS with respect to these three modes.For
this reason, the CLaMS 2.0 version implemented within the
Modular Earth Submodel System (MESSy), CLaMS 2.0/MESSy, is
applied with meteorology based on the ERA-Interim (EI) and
ERA5 (E5) reanalyses with the same horizontal resolution
(1.0×1.0∘) but with 60 and 137 model levels for EI and
E5, respectively. Comparisons with in situ observations are
used to rate the degree of agreement between different model
configurations and observations. Starting from pure
advective runs as a reference and in agreement with CLaMS
1.0, we show that among the three processes considered,
isentropic mixing dominates transport in the UTLS. Both the
observed CO, O3, N2O, and CO2 profiles and CO–O3
correlations are clearly better reproduced in the model with
isentropic mixing. The second most important transport
process considered is convection which is only partially
resolved in the vertical velocity fields provided by the
analysis. This additional pathway of transport from the
planetary boundary layer (PBL) to the main convective
outflow dominates the composition of air in the lower
stratosphere relative to the contribution of the resolved
transport. This transport happens mainly in the tropics and
sub-tropics, and significantly rejuvenates the age of air in
this region. By taking into account tropospheric mixing,
weakest changes in tracer distributions without any clear
improvements were found.},
cin = {IEK-7 / JSC},
ddc = {550},
cid = {I:(DE-Juel1)IEK-7-20101013 / I:(DE-Juel1)JSC-20090406},
pnm = {2112 - Climate Feedbacks (POF4-211) / 5111 -
Domain-Specific Simulation $\&$ Data Life Cycle Labs (SDLs)
and Research Groups (POF4-511)},
pid = {G:(DE-HGF)POF4-2112 / G:(DE-HGF)POF4-5111},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000865444800001},
doi = {10.5194/gmd-15-7471-2022},
url = {https://juser.fz-juelich.de/record/910157},
}