Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt
Warm conveyor belts (WCBs) are important airstreams in extratropical cyclones, often leading to the formation of intense precipitation and the amplification of upper-level ridges. This study presents a case study that involves aircraft, lidar and radar observations in a WCB ascending from western Eu...
Published in: | Atmospheric Chemistry and Physics |
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Main Authors: | , , , , , , , , , , , |
Format: | Other Non-Article Part of Journal/Newspaper |
Language: | English |
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Copernicus Publications
2021
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Online Access: | https://elib.dlr.de/142110/ https://elib.dlr.de/142110/1/acp-21-5477-2021.pdf https://acp.copernicus.org/articles/21/5477/2021/acp-21-5477-2021.html |
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ftdlr:oai:elib.dlr.de:142110 |
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openpolar |
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Open Polar |
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German Aerospace Center: elib - DLR electronic library |
op_collection_id |
ftdlr |
language |
English |
topic |
Lidar Wolkenphysik Atmosphärische Spurenstoffe |
spellingShingle |
Lidar Wolkenphysik Atmosphärische Spurenstoffe Boettcher, Maxi Schäfler, Andreas Sprenger, Michael Sodemann, Harald Kaufmann, Stefan Voigt, Christiane Schlager, Hans Summa, Donato Di Girolamo, Paolo Nerini, Daniele Germann, Urs Wernli, Heini Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
topic_facet |
Lidar Wolkenphysik Atmosphärische Spurenstoffe |
description |
Warm conveyor belts (WCBs) are important airstreams in extratropical cyclones, often leading to the formation of intense precipitation and the amplification of upper-level ridges. This study presents a case study that involves aircraft, lidar and radar observations in a WCB ascending from western Europe towards the Baltic Sea during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) and T-NAWDEX-Falcon in October 2012, a preparatory campaign for the THORPEX North Atlantic Waveguide and Downstream Impact Experiment (T-NAWDEX). Trajectories were used to link different observations along the WCB, that is, to establish so-called Lagrangian matches between observations. To this aim, an ensemble of wind fields from the global analyses produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) Ensemble of Data Assimilations (EDA) system were used, which allowed for a probabilistic quantification of the WCB occurrence and the Lagrangian matches. Despite severe air traffic limitations for performing research flights over Europe, the German Aerospace Center (DLR) Falcon successfully sampled WCB air masses during different phases of the WCB ascent. The WCB trajectories revealed measurements in two distinct WCB branches: one branch ascended from the eastern North Atlantic over southwestern France, while the other had its inflow in the western Mediterranean. Both branches passed across the Alps, and for both branches Lagrangian matches coincidentally occurred between lidar water vapour measurements in the inflow of the WCB south of the Alps, radar measurements during the ascent at the Alps and in situ aircraft measurements by Falcon in the WCB outflow north of the Alps. An airborne release experiment with an inert tracer could confirm the long pathway of the WCB from the inflow in the Mediterranean boundary layer to the outflow in the upper troposphere near the Baltic Sea several hours later. The comparison of observations and ensemble analyses reveals a moist bias in the analyses in parts of the WCB inflow but a good agreement of cloud water species in the WCB during ascent. In between these two observations, a precipitation radar measured strongly precipitating WCB air located directly above the melting layer while ascending at the southern slopes of the Alps. The trajectories illustrate the complexity of a continental and orographically influenced WCB, which leads to (i) WCB moisture sources from both the Atlantic and Mediterranean, (ii) different pathways of WCB ascent affected by orography, and (iii) locally steep WCB ascent with high radar reflectivity values that might result in enhanced precipitation where the WCB flows over the Alps. The linkage of observational data by ensemble-based WCB trajectory calculations, the confirmation of the WCB transport by an inert tracer and the model evaluation using the multi-platform observations are the central elements of this study and reveal important aspects of orographically modified WCBs. |
format |
Other Non-Article Part of Journal/Newspaper |
author |
Boettcher, Maxi Schäfler, Andreas Sprenger, Michael Sodemann, Harald Kaufmann, Stefan Voigt, Christiane Schlager, Hans Summa, Donato Di Girolamo, Paolo Nerini, Daniele Germann, Urs Wernli, Heini |
author_facet |
Boettcher, Maxi Schäfler, Andreas Sprenger, Michael Sodemann, Harald Kaufmann, Stefan Voigt, Christiane Schlager, Hans Summa, Donato Di Girolamo, Paolo Nerini, Daniele Germann, Urs Wernli, Heini |
author_sort |
Boettcher, Maxi |
title |
Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
title_short |
Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
title_full |
Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
title_fullStr |
Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
title_full_unstemmed |
Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
title_sort |
lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://elib.dlr.de/142110/ https://elib.dlr.de/142110/1/acp-21-5477-2021.pdf https://acp.copernicus.org/articles/21/5477/2021/acp-21-5477-2021.html |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://elib.dlr.de/142110/1/acp-21-5477-2021.pdf Boettcher, Maxi und Schäfler, Andreas und Sprenger, Michael und Sodemann, Harald und Kaufmann, Stefan und Voigt, Christiane und Schlager, Hans und Summa, Donato und Di Girolamo, Paolo und Nerini, Daniele und Germann, Urs und Wernli, Heini (2021) Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt. Atmospheric Chemistry and Physics (ACP), 21, Seiten 5477-5498. Copernicus Publications. doi:10.5194/acp-21-5477-2021 <https://doi.org/10.5194/acp-21-5477-2021>. ISSN 1680-7316. |
op_doi |
https://doi.org/10.5194/acp-21-5477-2021 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
21 |
container_issue |
7 |
container_start_page |
5477 |
op_container_end_page |
5498 |
_version_ |
1766132638597251072 |
spelling |
ftdlr:oai:elib.dlr.de:142110 2023-05-15T17:33:58+02:00 Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt Boettcher, Maxi Schäfler, Andreas Sprenger, Michael Sodemann, Harald Kaufmann, Stefan Voigt, Christiane Schlager, Hans Summa, Donato Di Girolamo, Paolo Nerini, Daniele Germann, Urs Wernli, Heini 2021-04-08 application/pdf https://elib.dlr.de/142110/ https://elib.dlr.de/142110/1/acp-21-5477-2021.pdf https://acp.copernicus.org/articles/21/5477/2021/acp-21-5477-2021.html en eng Copernicus Publications https://elib.dlr.de/142110/1/acp-21-5477-2021.pdf Boettcher, Maxi und Schäfler, Andreas und Sprenger, Michael und Sodemann, Harald und Kaufmann, Stefan und Voigt, Christiane und Schlager, Hans und Summa, Donato und Di Girolamo, Paolo und Nerini, Daniele und Germann, Urs und Wernli, Heini (2021) Lagrangian matches between observations from aircraft, lidar and radar in an orographic warm conveyor belt. Atmospheric Chemistry and Physics (ACP), 21, Seiten 5477-5498. Copernicus Publications. doi:10.5194/acp-21-5477-2021 <https://doi.org/10.5194/acp-21-5477-2021>. ISSN 1680-7316. Lidar Wolkenphysik Atmosphärische Spurenstoffe Zeitschriftenbeitrag PeerReviewed 2021 ftdlr https://doi.org/10.5194/acp-21-5477-2021 2021-05-09T23:05:09Z Warm conveyor belts (WCBs) are important airstreams in extratropical cyclones, often leading to the formation of intense precipitation and the amplification of upper-level ridges. This study presents a case study that involves aircraft, lidar and radar observations in a WCB ascending from western Europe towards the Baltic Sea during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) and T-NAWDEX-Falcon in October 2012, a preparatory campaign for the THORPEX North Atlantic Waveguide and Downstream Impact Experiment (T-NAWDEX). Trajectories were used to link different observations along the WCB, that is, to establish so-called Lagrangian matches between observations. To this aim, an ensemble of wind fields from the global analyses produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) Ensemble of Data Assimilations (EDA) system were used, which allowed for a probabilistic quantification of the WCB occurrence and the Lagrangian matches. Despite severe air traffic limitations for performing research flights over Europe, the German Aerospace Center (DLR) Falcon successfully sampled WCB air masses during different phases of the WCB ascent. The WCB trajectories revealed measurements in two distinct WCB branches: one branch ascended from the eastern North Atlantic over southwestern France, while the other had its inflow in the western Mediterranean. Both branches passed across the Alps, and for both branches Lagrangian matches coincidentally occurred between lidar water vapour measurements in the inflow of the WCB south of the Alps, radar measurements during the ascent at the Alps and in situ aircraft measurements by Falcon in the WCB outflow north of the Alps. An airborne release experiment with an inert tracer could confirm the long pathway of the WCB from the inflow in the Mediterranean boundary layer to the outflow in the upper troposphere near the Baltic Sea several hours later. The comparison of observations and ensemble analyses reveals a moist bias in the analyses in parts of the WCB inflow but a good agreement of cloud water species in the WCB during ascent. In between these two observations, a precipitation radar measured strongly precipitating WCB air located directly above the melting layer while ascending at the southern slopes of the Alps. The trajectories illustrate the complexity of a continental and orographically influenced WCB, which leads to (i) WCB moisture sources from both the Atlantic and Mediterranean, (ii) different pathways of WCB ascent affected by orography, and (iii) locally steep WCB ascent with high radar reflectivity values that might result in enhanced precipitation where the WCB flows over the Alps. The linkage of observational data by ensemble-based WCB trajectory calculations, the confirmation of the WCB transport by an inert tracer and the model evaluation using the multi-platform observations are the central elements of this study and reveal important aspects of orographically modified WCBs. Other Non-Article Part of Journal/Newspaper North Atlantic German Aerospace Center: elib - DLR electronic library Atmospheric Chemistry and Physics 21 7 5477 5498 |