Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS)
The Arctic climate is changing; temperature changes in the Arctic are greater than at midlatitudes, and changing atmospheric conditions influence Arctic mixed-phase clouds, which are important for the Arctic surface energy budget. These low-level clouds are frequently observed across the Arctic....
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2017-06-01
|
Series: | Atmospheric Chemistry and Physics |
Online Access: | http://www.atmos-chem-phys.net/17/6693/2017/acp-17-6693-2017.pdf |
id |
doaj-61144130d8e74c5ca065c227b1101043 |
---|---|
record_format |
Article |
spelling |
doaj-61144130d8e74c5ca065c227b11010432020-11-24T23:21:44ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242017-06-01176693670410.5194/acp-17-6693-2017Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS)K. Loewe0A. M. L. Ekman1M. Paukert2M. Paukert3J. Sedlar4M. Tjernström5C. Hoose6Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karslruhe, GermanyDepartment of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, SwedenInstitute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karslruhe, Germanynow at: Pacific Northwest National Laboratory, Richland, Washington, USASwedish Meteorological Hydrological Institute, Norrköping, SwedenDepartment of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, SwedenInstitute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karslruhe, GermanyThe Arctic climate is changing; temperature changes in the Arctic are greater than at midlatitudes, and changing atmospheric conditions influence Arctic mixed-phase clouds, which are important for the Arctic surface energy budget. These low-level clouds are frequently observed across the Arctic. They impact the turbulent and radiative heating of the open water, snow, and sea-ice-covered surfaces and influence the boundary layer structure. Therefore the processes that affect mixed-phase cloud life cycles are extremely important, yet relatively poorly understood. In this study, we present sensitivity studies using semi-idealized large eddy simulations (LESs) to identify processes contributing to the dissipation of Arctic mixed-phase clouds. We found that one potential main contributor to the dissipation of an observed Arctic mixed-phase cloud, during the Arctic Summer Cloud Ocean Study (ASCOS) field campaign, was a low cloud droplet number concentration (CDNC) of about 2 cm<sup>−3</sup>. Introducing a high ice crystal concentration of 10 L<sup>−1</sup> also resulted in cloud dissipation, but such high ice crystal concentrations were deemed unlikely for the present case. Sensitivity studies simulating the advection of dry air above the boundary layer inversion, as well as a modest increase in ice crystal concentration of 1 L<sup>−1</sup>, did not lead to cloud dissipation. As a requirement for small droplet numbers, pristine aerosol conditions in the Arctic environment are therefore considered an important factor determining the lifetime of Arctic mixed-phase clouds.http://www.atmos-chem-phys.net/17/6693/2017/acp-17-6693-2017.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
K. Loewe A. M. L. Ekman M. Paukert M. Paukert J. Sedlar M. Tjernström C. Hoose |
spellingShingle |
K. Loewe A. M. L. Ekman M. Paukert M. Paukert J. Sedlar M. Tjernström C. Hoose Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS) Atmospheric Chemistry and Physics |
author_facet |
K. Loewe A. M. L. Ekman M. Paukert M. Paukert J. Sedlar M. Tjernström C. Hoose |
author_sort |
K. Loewe |
title |
Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS) |
title_short |
Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS) |
title_full |
Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS) |
title_fullStr |
Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS) |
title_full_unstemmed |
Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS) |
title_sort |
modelling micro- and macrophysical contributors to the dissipation of an arctic mixed-phase cloud during the arctic summer cloud ocean study (ascos) |
publisher |
Copernicus Publications |
series |
Atmospheric Chemistry and Physics |
issn |
1680-7316 1680-7324 |
publishDate |
2017-06-01 |
description |
The Arctic climate is changing; temperature changes in the Arctic are greater
than at midlatitudes, and changing atmospheric conditions influence Arctic
mixed-phase clouds, which are important for the Arctic surface energy budget.
These low-level clouds are frequently observed across the Arctic. They impact
the turbulent and radiative heating of the open water, snow, and
sea-ice-covered surfaces and influence the boundary layer structure.
Therefore the processes that affect mixed-phase cloud life cycles are
extremely important, yet relatively poorly understood. In this study, we
present sensitivity studies using semi-idealized large eddy simulations
(LESs) to identify processes contributing to the dissipation of Arctic
mixed-phase clouds. We found that one potential main contributor to the
dissipation of an observed Arctic mixed-phase cloud, during the Arctic Summer
Cloud Ocean Study (ASCOS) field campaign, was a low cloud droplet number
concentration (CDNC) of about 2 cm<sup>−3</sup>. Introducing a high ice
crystal concentration of 10 L<sup>−1</sup> also resulted in cloud
dissipation, but such high ice crystal concentrations were deemed unlikely
for the present case. Sensitivity studies simulating the advection of dry air
above the boundary layer inversion, as well as a modest increase in ice
crystal concentration of 1 L<sup>−1</sup>, did not lead to cloud dissipation.
As a requirement for small droplet numbers, pristine aerosol conditions in
the Arctic environment are therefore considered an important factor
determining the lifetime of Arctic mixed-phase clouds. |
url |
http://www.atmos-chem-phys.net/17/6693/2017/acp-17-6693-2017.pdf |
work_keys_str_mv |
AT kloewe modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos AT amlekman modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos AT mpaukert modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos AT mpaukert modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos AT jsedlar modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos AT mtjernstrom modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos AT choose modellingmicroandmacrophysicalcontributorstothedissipationofanarcticmixedphasecloudduringthearcticsummercloudoceanstudyascos |
_version_ |
1725570193921409024 |