Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact
Warm conveyor belts (WCBs) are dynamically important, strongly ascending and mostly stratiform cloud-forming airstreams in extratropical cyclones. Despite the predominantly stratiform character of the WCB's large-scale cloud band, convective clouds can be embedded in it. This embedded convectio...
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Copernicus Publications
2021
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Online Access: | https://publikationen.bibliothek.kit.edu/1000129005 https://publikationen.bibliothek.kit.edu/1000129005/100592847 https://doi.org/10.5445/IR/1000129005 |
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ftubkarlsruhe:oai:EVASTAR-Karlsruhe.de:1000129005 2023-05-15T17:35:53+02:00 Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact Oertel, Annika Sprenger, Michael Joos, Hanna Boettcher, Maxi Konow, Heike Hagen, Martin Wernli, Heini 2021-01-26 application/pdf https://publikationen.bibliothek.kit.edu/1000129005 https://publikationen.bibliothek.kit.edu/1000129005/100592847 https://doi.org/10.5445/IR/1000129005 eng eng Copernicus Publications info:eu-repo/semantics/altIdentifier/doi/10.5194/wcd-2020-49 https://publikationen.bibliothek.kit.edu/1000129005 https://publikationen.bibliothek.kit.edu/1000129005/100592847 https://doi.org/10.5445/IR/1000129005 https://creativecommons.org/licenses/by/4.0/deed.de info:eu-repo/semantics/openAccess CC-BY ddc:550 Earth sciences info:eu-repo/classification/ddc/550 doc-type:report Text info:eu-repo/semantics/book monograph info:eu-repo/semantics/publishedVersion 2021 ftubkarlsruhe https://doi.org/10.5445/IR/1000129005 https://doi.org/10.5194/wcd-2020-49 2022-03-23T17:09:18Z Warm conveyor belts (WCBs) are dynamically important, strongly ascending and mostly stratiform cloud-forming airstreams in extratropical cyclones. Despite the predominantly stratiform character of the WCB's large-scale cloud band, convective clouds can be embedded in it. This embedded convection leads to a heterogeneously structured cloud band with locally enhanced hydrometeor content, intense surface precipitation and substantial amounts of graupel in the middle troposhere. Recent studies showed that embedded convection forms dynamically relevant quasi-horizontal potential vorticity (PV) dipoles in the upper troposphere. Thereby one pole can reach strongly negative PV values associated with inertial or symmetric instability near the upper-level PV waveguide, where it can interact with and modify the upper-level jet. This study analyses the characteristics of embedded convection in the WCB of cyclone Sanchez based on WCB online trajectories from a convection-permitting simulation and airborne radar observations during the North Atlantic Waveguide and Downstream Impact EXperiment (NAWDEX) field campaign (IOPs 10 and 11). In the first part, we present the radar reflectivity structure of the WCB and corroborate its heterogeneous cloud structure and the occurrence of embedded convection. Radar observations in three different sub-regions of the WCB cloud band reveal the differing intensity of its embedded convection, which is qualitatively confirmed by the ascent rates of the online WCB trajectories. The detailed ascent behaviour of the WCB trajectories reveals that very intense convection with ascent rates of 600 hPa in 30–60 min occurs, in addition to comparatively moderate convection with slower ascent velocities as reported in previous case studies. In the second part of this study, a systematic Lagrangian composite analysis based on online trajectories for two sub-categories of WCB-embedded convection – moderate and intense convection – is performed. Composites of the cloud and precipitation structure confirm ... Book North Atlantic KITopen (Karlsruhe Institute of Technologie) |
institution |
Open Polar |
collection |
KITopen (Karlsruhe Institute of Technologie) |
op_collection_id |
ftubkarlsruhe |
language |
English |
topic |
ddc:550 Earth sciences info:eu-repo/classification/ddc/550 |
spellingShingle |
ddc:550 Earth sciences info:eu-repo/classification/ddc/550 Oertel, Annika Sprenger, Michael Joos, Hanna Boettcher, Maxi Konow, Heike Hagen, Martin Wernli, Heini Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
topic_facet |
ddc:550 Earth sciences info:eu-repo/classification/ddc/550 |
description |
Warm conveyor belts (WCBs) are dynamically important, strongly ascending and mostly stratiform cloud-forming airstreams in extratropical cyclones. Despite the predominantly stratiform character of the WCB's large-scale cloud band, convective clouds can be embedded in it. This embedded convection leads to a heterogeneously structured cloud band with locally enhanced hydrometeor content, intense surface precipitation and substantial amounts of graupel in the middle troposhere. Recent studies showed that embedded convection forms dynamically relevant quasi-horizontal potential vorticity (PV) dipoles in the upper troposphere. Thereby one pole can reach strongly negative PV values associated with inertial or symmetric instability near the upper-level PV waveguide, where it can interact with and modify the upper-level jet. This study analyses the characteristics of embedded convection in the WCB of cyclone Sanchez based on WCB online trajectories from a convection-permitting simulation and airborne radar observations during the North Atlantic Waveguide and Downstream Impact EXperiment (NAWDEX) field campaign (IOPs 10 and 11). In the first part, we present the radar reflectivity structure of the WCB and corroborate its heterogeneous cloud structure and the occurrence of embedded convection. Radar observations in three different sub-regions of the WCB cloud band reveal the differing intensity of its embedded convection, which is qualitatively confirmed by the ascent rates of the online WCB trajectories. The detailed ascent behaviour of the WCB trajectories reveals that very intense convection with ascent rates of 600 hPa in 30–60 min occurs, in addition to comparatively moderate convection with slower ascent velocities as reported in previous case studies. In the second part of this study, a systematic Lagrangian composite analysis based on online trajectories for two sub-categories of WCB-embedded convection – moderate and intense convection – is performed. Composites of the cloud and precipitation structure confirm ... |
format |
Book |
author |
Oertel, Annika Sprenger, Michael Joos, Hanna Boettcher, Maxi Konow, Heike Hagen, Martin Wernli, Heini |
author_facet |
Oertel, Annika Sprenger, Michael Joos, Hanna Boettcher, Maxi Konow, Heike Hagen, Martin Wernli, Heini |
author_sort |
Oertel, Annika |
title |
Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
title_short |
Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
title_full |
Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
title_fullStr |
Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
title_full_unstemmed |
Observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
title_sort |
observations and simulation of intense convection embedded in a warm conveyor belt – how ambient vertical wind shear determines the dynamical impact |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://publikationen.bibliothek.kit.edu/1000129005 https://publikationen.bibliothek.kit.edu/1000129005/100592847 https://doi.org/10.5445/IR/1000129005 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/wcd-2020-49 https://publikationen.bibliothek.kit.edu/1000129005 https://publikationen.bibliothek.kit.edu/1000129005/100592847 https://doi.org/10.5445/IR/1000129005 |
op_rights |
https://creativecommons.org/licenses/by/4.0/deed.de info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5445/IR/1000129005 https://doi.org/10.5194/wcd-2020-49 |
_version_ |
1766135189801533440 |