Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery
Polar mesoscale cyclones over the subarctic are thought to be an important component of the coupled atmosphere–ocean climate system. However, the relatively small scale of these features presents some concern as to their representation in the meteorological reanalysis datasets that are commonly used...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.529.8533 2023-05-15T17:41:09+02:00 Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery Alan Condron Grant R. Bigg Ian A. Renfrew The Pennsylvania State University CiteSeerX Archives 2006 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.529.8533 http://www.uea.ac.uk/~e046/reprints/condron_etal_polar_mesocyclones_reprint2006.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.529.8533 http://www.uea.ac.uk/~e046/reprints/condron_etal_polar_mesocyclones_reprint2006.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.uea.ac.uk/~e046/reprints/condron_etal_polar_mesocyclones_reprint2006.pdf text 2006 ftciteseerx 2020-07-05T00:15:33Z Polar mesoscale cyclones over the subarctic are thought to be an important component of the coupled atmosphere–ocean climate system. However, the relatively small scale of these features presents some concern as to their representation in the meteorological reanalysis datasets that are commonly used to drive ocean models. Here polar mesocyclones are detected in the 40-Year European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis dataset (ERA-40) in mean sea level pressure and 500-hPa geopotential height, using an automated cyclone detection algorithm. The results are compared to polar mesocyclones detected in satellite imagery over the northeast Atlantic, for the period October 1993– September 1995. Similar trends in monthly cyclone numbers and a similar spatial distribution are found. However, there is a bias in the size of cyclones detected in the reanalysis. Up to 80 % of cyclones larger than 500 km are detected in MSL pressure, but this hit rate decreases, approximately linearly, to 40 % for 250-km-scale cyclones and to 20 % for 100-km-scale cyclones. Consequently a substantial component of the associated air–sea fluxes may be missing from the reanalysis, presenting a serious shortcoming when using such reanalysis data for ocean modeling simulations. Eight maxima in cyclone density are apparent in the mean sea level pressure, clustered around synoptic observing stations in the northeast Atlantic. They are likely spurious, and a result of unidentified shortcomings in the ERA-40 data assimilation procedure. Text Northeast Atlantic Subarctic Unknown |
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Polar mesoscale cyclones over the subarctic are thought to be an important component of the coupled atmosphere–ocean climate system. However, the relatively small scale of these features presents some concern as to their representation in the meteorological reanalysis datasets that are commonly used to drive ocean models. Here polar mesocyclones are detected in the 40-Year European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis dataset (ERA-40) in mean sea level pressure and 500-hPa geopotential height, using an automated cyclone detection algorithm. The results are compared to polar mesocyclones detected in satellite imagery over the northeast Atlantic, for the period October 1993– September 1995. Similar trends in monthly cyclone numbers and a similar spatial distribution are found. However, there is a bias in the size of cyclones detected in the reanalysis. Up to 80 % of cyclones larger than 500 km are detected in MSL pressure, but this hit rate decreases, approximately linearly, to 40 % for 250-km-scale cyclones and to 20 % for 100-km-scale cyclones. Consequently a substantial component of the associated air–sea fluxes may be missing from the reanalysis, presenting a serious shortcoming when using such reanalysis data for ocean modeling simulations. Eight maxima in cyclone density are apparent in the mean sea level pressure, clustered around synoptic observing stations in the northeast Atlantic. They are likely spurious, and a result of unidentified shortcomings in the ERA-40 data assimilation procedure. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Alan Condron Grant R. Bigg Ian A. Renfrew |
spellingShingle |
Alan Condron Grant R. Bigg Ian A. Renfrew Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery |
author_facet |
Alan Condron Grant R. Bigg Ian A. Renfrew |
author_sort |
Alan Condron |
title |
Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery |
title_short |
Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery |
title_full |
Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery |
title_fullStr |
Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery |
title_full_unstemmed |
Polar mesoscale cyclones in the northeast Atlantic: Comparing climatologies from ERA-40 and satellite imagery |
title_sort |
polar mesoscale cyclones in the northeast atlantic: comparing climatologies from era-40 and satellite imagery |
publishDate |
2006 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.529.8533 http://www.uea.ac.uk/~e046/reprints/condron_etal_polar_mesocyclones_reprint2006.pdf |
genre |
Northeast Atlantic Subarctic |
genre_facet |
Northeast Atlantic Subarctic |
op_source |
http://www.uea.ac.uk/~e046/reprints/condron_etal_polar_mesocyclones_reprint2006.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.529.8533 http://www.uea.ac.uk/~e046/reprints/condron_etal_polar_mesocyclones_reprint2006.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766142451416825856 |