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@PHDTHESIS{BartolomGarca:905740,
author = {Bartolomé García, Irene},
title = {{C}irrus clouds in the extratropical tropopause and
lowermost stratosphere region},
volume = {566},
school = {Bergische Universität Wuppertal},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2022-00964},
isbn = {978-3-95806-610-6},
series = {Schriften des Forschungszentrums Jülich Reihe. Energie
$\&$ Umwelt / Energy $\&$ Environment},
pages = {iii, 155 S.},
year = {2022},
note = {Bergische Universität Wuppertal, Diss., 2021},
abstract = {Cirrus clouds play a fundamental role in the radiative
balance of the Earth and have an important impact on the
climate. Their net effect depends on their physical
characteristics, i.e., altitude, vertical extent, optical
thickness and particle size. Quantifying the properties of
ice crystals from the observations is a very challenging
task. Consequently, models used for climate projections lack
observational constrains when predicting the processes
related to the evolution of cirrus and their properties. The
aim of this thesis was to gain a deeper understanding of
cirrus macro-physical properties (cloud top and bottom
height, vertical extent, position with respect to the
tropopause) and of the micro-physical properties (ice water
content (IWC), particle size). For this purpose, data
measured by GLORIA (Gimballed Limb Observation for Radiance
Imaging of the Atmosphere) during the WISE (Wave-driven
ISentropic Exchange) campaign were analyzed. GLORIA is an
airborne limb remote sensor that measures radiance in the
thermal infrared region (700 cm$^{−1}$ to
1400cm$^{−1}$). Two identification methods were used to
detect clouds in the measurements. One method is based on
the cloud index (CI) and the other method, on the use of the
extinction coefficient in the spectral range 832cm$^{−1}$
to 834cm$^{−1}$. Between 13 – 27\% of the total number
of observations presented a cloud top located above the
tropopause(TP). However, no cirrus layers were found
unambiguously above the TP (i.e., both cloud top and cloud
bottom above the TP). To estimate the micro-physical
properties a combination of two approaches was used. The IWC
was then integrated to obtain the ice water path (IWP). The
IWP was compared to the ERA5-based dataset, giving
satisfactory results (qualitatively) and highlighting that
the ERA5 reanalysis does not reproduce most of the very thin
clouds close to the tropopause. Quantitatively, the
retrieved IWP was smaller than the ERA5-based IWP, pointing
to the need of reducing uncertainties to obtain a more
accurate product. Additionally, observed cloudy regions
close to the TP were selected as case studies to simulate
with CLaMS-Ice (Chemical Lagrangian Model of the
Stratosphere). The model was able to sucessfully form clouds
in the region of interest.},
cin = {IEK-7},
cid = {I:(DE-Juel1)IEK-7-20101013},
pnm = {2112 - Climate Feedbacks (POF4-211)},
pid = {G:(DE-HGF)POF4-2112},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
url = {https://juser.fz-juelich.de/record/905740},
}