Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation
The ambient conditions during cyclogenesis on fronts in the North Atlantic (NA) are characterised climatologically in the ERA-Interim dataset. These ‘secondary’ cyclones, which grow from frontal waves, are typically small in scale, shallow and deepen rapidly, and pose a challenge to forecasters and...
Published in: | Quarterly Journal of the Royal Meteorological Society |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2015
|
Subjects: | |
Online Access: | https://hdl.handle.net/1956/11634 https://doi.org/10.1002/qj.2584 |
id |
ftunivbergen:oai:bora.uib.no:1956/11634 |
---|---|
record_format |
openpolar |
spelling |
ftunivbergen:oai:bora.uib.no:1956/11634 2023-05-15T17:31:39+02:00 Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation Schemm, Sebastian Sprenger, Michael 2015-12-16T15:44:50Z application/pdf https://hdl.handle.net/1956/11634 https://doi.org/10.1002/qj.2584 eng eng Wiley urn:issn:1477-870X https://hdl.handle.net/1956/11634 https://doi.org/10.1002/qj.2584 cristin:1301649 Attribution CC BY-NC http://creativecommons.org/licenses/by-nc/4.0/ Copyright 2015 The Authors frontal wave cyclogenesis Climatology along-frontal stretching potential vorticity deformation secondary cyclogenesis Peer reviewed Journal article 2015 ftunivbergen https://doi.org/10.1002/qj.2584 2023-03-14T17:41:38Z The ambient conditions during cyclogenesis on fronts in the North Atlantic (NA) are characterised climatologically in the ERA-Interim dataset. These ‘secondary’ cyclones, which grow from frontal waves, are typically small in scale, shallow and deepen rapidly, and pose a challenge to forecasters and numerical weather prediction models. Frontal-wave development has been studied intensively in the past based on observations (e.g. FASTEX), real-case studies or analytical models. In this study, frontal-wave cyclogenesis is studied from a climatological perspective and is detected by a combination of two automated identification methods for the period between 1979 and 2014. A climatology of frontal-wave cyclogenesis is presented. Horizontal composites provide an estimate of the climatological mean of conditions during frontal-wave cyclogenesis which may prove useful in the assessment of the realism of proposed idealized models of frontogenesis. The findings are also compared with assumptions made in earlier idealized studies of frontal waves. The composites reveal coherent structures of diabatically generated low-level PV in the lower troposphere, neutral moist static stability at cyclogenesis and an ambient lower troposphere close to saturation. The vertical PV structure in the east NA is more vertically aligned than in the west NA and PV anomalies from the upper and lower levels reach deeper into the mid-troposphere, which indicates an enhanced phase-lock between the two anomalies. Previous studies suggest the existence of an upper limit of along-frontal stretching above which frontal-wave development is strongly suppressed. The presented multi-decadal analysis confirms its existence in a range between 0.6 and 0.8 × 10−5 s−1. Finally a climatology of along-frontal stretching for the NA is presented and compared to the fraction of cyclogenesis forming on frontal waves. publishedVersion Article in Journal/Newspaper North Atlantic University of Bergen: Bergen Open Research Archive (BORA-UiB) Quarterly Journal of the Royal Meteorological Society 141 693 2989 3005 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
frontal wave cyclogenesis Climatology along-frontal stretching potential vorticity deformation secondary cyclogenesis |
spellingShingle |
frontal wave cyclogenesis Climatology along-frontal stretching potential vorticity deformation secondary cyclogenesis Schemm, Sebastian Sprenger, Michael Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation |
topic_facet |
frontal wave cyclogenesis Climatology along-frontal stretching potential vorticity deformation secondary cyclogenesis |
description |
The ambient conditions during cyclogenesis on fronts in the North Atlantic (NA) are characterised climatologically in the ERA-Interim dataset. These ‘secondary’ cyclones, which grow from frontal waves, are typically small in scale, shallow and deepen rapidly, and pose a challenge to forecasters and numerical weather prediction models. Frontal-wave development has been studied intensively in the past based on observations (e.g. FASTEX), real-case studies or analytical models. In this study, frontal-wave cyclogenesis is studied from a climatological perspective and is detected by a combination of two automated identification methods for the period between 1979 and 2014. A climatology of frontal-wave cyclogenesis is presented. Horizontal composites provide an estimate of the climatological mean of conditions during frontal-wave cyclogenesis which may prove useful in the assessment of the realism of proposed idealized models of frontogenesis. The findings are also compared with assumptions made in earlier idealized studies of frontal waves. The composites reveal coherent structures of diabatically generated low-level PV in the lower troposphere, neutral moist static stability at cyclogenesis and an ambient lower troposphere close to saturation. The vertical PV structure in the east NA is more vertically aligned than in the west NA and PV anomalies from the upper and lower levels reach deeper into the mid-troposphere, which indicates an enhanced phase-lock between the two anomalies. Previous studies suggest the existence of an upper limit of along-frontal stretching above which frontal-wave development is strongly suppressed. The presented multi-decadal analysis confirms its existence in a range between 0.6 and 0.8 × 10−5 s−1. Finally a climatology of along-frontal stretching for the NA is presented and compared to the fraction of cyclogenesis forming on frontal waves. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Schemm, Sebastian Sprenger, Michael |
author_facet |
Schemm, Sebastian Sprenger, Michael |
author_sort |
Schemm, Sebastian |
title |
Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation |
title_short |
Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation |
title_full |
Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation |
title_fullStr |
Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation |
title_full_unstemmed |
Frontal-wave cyclogenesis in the North Atlantic –a climatological characterisation |
title_sort |
frontal-wave cyclogenesis in the north atlantic –a climatological characterisation |
publisher |
Wiley |
publishDate |
2015 |
url |
https://hdl.handle.net/1956/11634 https://doi.org/10.1002/qj.2584 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
urn:issn:1477-870X https://hdl.handle.net/1956/11634 https://doi.org/10.1002/qj.2584 cristin:1301649 |
op_rights |
Attribution CC BY-NC http://creativecommons.org/licenses/by-nc/4.0/ Copyright 2015 The Authors |
op_doi |
https://doi.org/10.1002/qj.2584 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
141 |
container_issue |
693 |
container_start_page |
2989 |
op_container_end_page |
3005 |
_version_ |
1766129325102333952 |