Lamb weather types (reduced set) and gale days over the North Sea since 1948 based on NCEP/NCAR Reanalysis 1 daily mean sea level pressure fields

Sea level pressure is a fundamental weather and climate element and the very basis of everyday weather maps. Daily sea level pressure distributions provide information on the influence of high and low pressure systems, air flow, weather activity, and, hence, synoptic conditions.

Using sea level pressure distributions from the NCEP/NCAR Reanalysis 1 (Kalnay et al., 1996) and a simplified variant of the weather-typing scheme by Jenkinson and Collison (1977) atmospheric circulation over the North Sea has been classified as to pattern and intensity on a daily basis starting in 1948. A full account of the original weather-typing scheme can be found in Loewe et al. (2005), while the variant scheme has been detailed in Loewe et al. (2006). The analysis has been carried out on the original 16-point grid. Though formally valid at its central point (55°N, 5°E), results are representative of the North Sea region between 50°N-60°N and 0°E-10°E.

The modified scheme allows for six weather types, namely four directional (NE=Northeast, SE, SW, NW) and two rotational types (C=cyclonic and A=anticyclonic). The strength of the atmospheric circulation is classified by way of a peak-over-threshold technique, employing re-calibrated thresholds for the gale index G* of 28.3, 36.6, and 44.6 hPa for gale (G), severe gale (SG), and very severe gale (VSG), respectively (Loewe et al., 2013). Technically, the set of weather-typing and gale-classification rules is implemented as a lean FORTRAN code (lwtnssim.f), internally known as "Simple Lamb weather-typing scheme for the North Sea v1". The processing run was done on a Linux server under Debian 10 (Buster).

Both, weather types and gale days, form a catalogue of more than 70 annual calendars since 1948 that is presented and continuously updated to the present day at https://www.bsh.de/EN/DATA/Climate-and-Sea/Weather-and-Gales/weather-and-gales_node.html. This catalogue concisely documents synoptic conditions in the North Sea region. Possible benefits are manifold. Special events and episodes in regional-scale atmospheric circulation are easily looked up and traced. Beyond that, the dataset is well suited for frequency, trend, persistence, transition, and extreme-value statistics.

 
Citation proposal
Peter Loewe (Bundesamt für Seeschifffahrt und Hydrographie). Lamb weather types (reduced set) and gale days over the North Sea since 1948 based on NCEP/NCAR Reanalysis 1 daily mean sea level pressure fields. https://gdk.gdi-de.org/geonetwork/srv/api/records/de.dkrz.wdcc.iso3893192
 

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File identifier
de.dkrz.wdcc.iso3893192   XML
Hierarchy level
series Series
Online resource
Resource identifier
code
None
Metadata language
eng English
Encoding
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NetCDF
Version
network Common Data Format
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Coupled resource
 
 

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Coupled resource
 
 

Keywords

Other keywords
Keywords ( Theme )
  • NCEP
Keywords ( Theme )
  • re-analysis
Keywords ( Theme )
  • Baltic Sea
Keywords ( Theme )
  • North Sea
Keywords ( Theme )
  • gale
Keywords ( Theme )
  • ATMODAT (v3.0)
Keywords ( Theme )
  • weather types
Keywords ( Theme )
  • atmos
Keywords ( Theme )
  • Meteorology and atmospheric sciences
 
 

Geographic coverage

N
S
E
W


 

Temporal reference

Temporal extent
Begin
1948-01-01
End
2021-12-31
Temporal extent
Date ( Creation )
2022-02-07
 

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Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
 

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Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
 

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Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Organisation name
Bundesamt für Seeschifffahrt und Hydrographie
Date stamp
2022-02-18T04:25:23
 
 

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