A long‐term climatology of North Atlantic polar lows

Zahn, Matthias; Storch, Hans von

doi:10.1029/2008gl035769

Cited by 84 publications

(111 citation statements)

References 27 publications

(36 reference statements)

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“…On average, we find 12 polar-low events per year compared with seven found by Wilhelmsen (1985). Based on the finding of Zahn and von Storch (2008) that there is no significant trend in the polarlow frequency from 1948 up to the present, we believe that this difference is mainly due to differences in methods. The study of Wilhelmsen almost solely relied on meteorological weather maps, which were mainly based on conventional observations.…”

Section: Statistical Resultsmentioning

confidence: 46%

“…The study by Zahn and von Storch (2008) found no significant trend in the polar-low frequency from 1948 to the present. We will assume that this result is valid and also add the data from Wilhelmsen to ours to get a total data set of 21 years.…”

Section: Introductionmentioning

confidence: 96%

“…Differences in methodology and study areas are to a large extent the cause for this. Zahn and von Storch (2008) investigated the polarlow climatology of the North Atlantic by dynamical downscaling of the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis for the period 1948-2006, i.e. a limited-area atmospheric model for the study area was nested into the NCEP/NCAR reanalysis.…”

Section: Introductionmentioning

confidence: 99%

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A climatological study of polar lows in the Nordic Seas

Noer¹,

Sætra²,

Lien³

et al. 2011

Quart J Royal Meteoro Soc

110

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The climatology of polar lows over the Nordic Seas has been investigated using infrared satellite images for the period between 2000 and 2009. The same region was studied in the 1980s using traditional weather charts for the period between 1972 and 1982. One motivation for the present study was to revisit this climatology, but using a different decade and taking advantage of the vastly improved coverage and dissemination of infrared satellite images since the 1980s. The fact that forecasters at the Norwegian Meteorological Institute had introduced a routine to register polar-low events systematically from 2000 and onward also provided a unique opportunity for extending the existing repository of subjectively identified polarlow observations. On average we found 12 polar-low events per year in the region of study. This is more than the earlier investigation, but we believe that this can be explained by the fact that the previous study relied almost uniquely on weather charts with very little information from ocean areas in the Nordic Seas. The largest numbers were found in January with an average of 2.8 polar-low events per year. The study reconfirms the February minimum found in previous studies, but on the basis of our data we could not show that this minimum is statistically significant. It is suggested that this may be explained as a manifestation of the coldest winter month, when a surface-pressure high over the Scandinavian mainland is common and the large-scale atmospheric flow is less favourable to polar-low formation. This hypothesis was tested by calculating the mean sea-level pressure (MSLP) anomaly for January, February and March from an atmospheric reanalysis. This revealed a positive anomaly over Scandinavia and northwest Russia not found in the pressure distributions for January and March.

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Section: Statistical Resultsmentioning

confidence: 46%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A climatological study of polar lows in the Nordic Seas

Noer¹,

Sætra²,

Lien³

et al. 2011

Quart J Royal Meteoro Soc

110

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“…COSMO-CLM has been widely used for climatic studies not only over the European continent, Mediterranean Sea and Atlantic Coast (Rockel et al 2008), but also for studying North Atlantic Polar Lows (Zahn and von Storch 2008b), East Asian typhoons (Feser and von Storch 2008) and "Medicanes" in the Mediterranean Sea (Cavicchia and von Storch 2012).…”

Section: Model Usedmentioning

confidence: 99%

“…Polar Lows in the North Atlantic (Zahn and von Storch 2008b) as well as for typhoons in East Asia (Feser and von Storch 2008) are two such sub-synoptic phenomena, thus a methodology has been developed recently to construct a homogeneous data base for the formation and life cycles of such sub-synoptic disturbances. "Homogeneous" refers here to the property that changes in the data base are most likely reflecting changes in the physical reality and not changes in the observational-analytical process.…”

Section: Purpose Of This Studymentioning

confidence: 99%

Toward a Multi-Decadal Climatology of North Pacific Polar Lows Employing Dynamical Downscaling

Chen¹,

Geyer²,

Zahn³

et al. 2012

Terr. Atmos. Ocean. Sci.

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The North Pacific is an area where sub-synoptic Polar Lows frequently form during the cold season, especially over the Bering Sea, Gulf of Alaska and Japan Sea. So far, a multi-decadal climatology of such Polar Lows based on individual cases has not been assembled. Here, we consider dynamical downscaling method for realistically constructing the formation and life cycles of such lows over the past 6 decades without exploiting sub-synoptic information in initial fields. To do so, a regional climate model is conditioned by large-scale information of NCEP re-analyses. We test the approach by examining its skill in simulating ten known cases of North Pacific Polar Lows. Three of these are discussed in some detail.The signatures of all storms emerge in the simulations with additional sub-synoptic details. The tracks of the simulated Polar Lows closely follow the tracks derived from satellite imagery. We conclude that the suggested method is suitable for constructing multi-decade climatologies, including trends and variability, of Polar Lows in the North Pacific by dynamically downscaling NCEP re-analyses.

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New view of Arctic cyclone activity from the Arctic system reanalysis

Tilinina

Gulev

Bromwich

2014

Geophysical Research Letters

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Arctic cyclone activity is analyzed in 11 year (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), 3-hourly output from the Arctic System Reanalysis (ASR) interim version. Compared to the global modern era reanalyses (European Centre for Medium-Range Weather Forecasts Reanalysis (ERA)-Interim, Modern Era Retrospective Analysis for Research and Applications, and National Centers for Environmental Prediction-Climate Forecast System Reanalysis), ASR shows a considerably higher number of cyclones over the Arctic with the largest differences over the high-latitude continental areas (up to 40% in summer and 30% in winter). Over the Arctic Ocean during both seasons ASR captures well the cyclone maximum in the Eastern Arctic which has 30% less cyclones in summer and is hardly detectable in winter in ERA-Interim. High resolution of the ASR model coupled with more comprehensive data assimilation allows for more accurate (compared to the global reanalyses) description of the life cycle of the most intense Arctic cyclones, for which ASR shows lower central pressure (4 hPa on average), faster deepening, and stronger winds on average.

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A long‐term climatology of North Atlantic polar lows

Cited by 84 publications

References 27 publications

A climatological study of polar lows in the Nordic Seas

A climatological study of polar lows in the Nordic Seas

Toward a Multi-Decadal Climatology of North Pacific Polar Lows Employing Dynamical Downscaling

New view of Arctic cyclone activity from the Arctic system reanalysis

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