North Sea Weather Report 2015/16
Transcription
North Sea Weather Report 2015/16
MAKE INFORMED DECISIONS Marine forecasts are integral to operational planning. With accurate assessments of the weather and sea-state, you can deploy resources efficiently, safely and on time. Our forecasts are underpinned by our science expertise, which extends much further than forecasting the weather. Our science team is extensive and provides a range of marine services that span hindcast data sets and routine weather window analysis, right through to atmospheric dispersion modelling and sea bed temperature forecasting. Our science consultancy services include bespoke analyses, studies and expert advice. Downtime analyses can be tailored to operations with multiple elements and thresholds, including ‘stopstart’ and ‘must complete’ criteria. Research has included providing guidance for: effective capture and use of metocean data through a project lifecycle; mapping of the marine climate and assessing impacts of climate change; contextualising recent stormy winters; and providing expert witness services for legal cases. Make informed decisions with our validated historical metocean dataset, science consultancy and forecast services. For more information call us on +44(0)1224 629831 or email marine@metoffice.gov.uk Met Office Lord Cullen House Fraser Place Aberdeen AB25 3UB Tel: +44(0)1224 629831 Email: marine@metoffice.gov.uk www.metoffice.gov.uk/marine Produced by the Met Office. © Crown copyright 2016 16/0671 Met Office and the Met Office logo are registered trademarks Marine North Sea weather analysis – October 2015-February 2016 The late autumn and winter of 2015/16 was a relatively average season. Both monthly mean wind speeds and wave heights were close to or slightly above the long-term averages, whilst the majority of monthly maximums were below the long-term maximum. This period saw the introduction of the naming of significant storm events, a joint project between the Met Office and Met Éireann, the Irish Met Service. Between November and February, nine named storms occurred, which is not an unusual number of events for the time of year. Storm Gertrude, at the end of January, produced the largest wind speeds and wave heights of these nine storms. A COMPARISON WITH LONGTERM AVERAGES Met Office model data, extending from 1980 to the present day, has been analysed to compare the wind and wave heights for the period October 2015 to February 2016, against the 1980-2014 long-term statistics. The analysis has been undertaken at four locations representing the West of Shetland, Northern, Central and Southern North Sea (shown in figure 1). For each location we compare the 2015/2016 monthly mean and maximum waves and winds against the longterm values (Figures 2 and 3). The mean values are shown by the line graphs and the maximum values by the bar graphs. The data tells us that across all locations monthly averages of wave heights and wind speeds were very close to the long-term averages. The exceptions are for November and December for the West of Shetland and Northern North Sea, where wave heights were up to a meter above the long-term average. For example, in December in the Northern North Sea the average monthly wave height was 4.6m, compared against a long term average of 3.5m. Monthly maximums were all below the long-term maximums, with the exception of January where a new maximum significant wave height and mean wind speed in the Northern North Sea were generated in the model. A new maximum mean wind speed also occurred West of Shetland. Figure 1 location of analyses Figure 2 Analyses of wave heights STORM GERTRUDE On 29 January, storm Gertrude brought gusts of 60 to 70 knots or more to exposed coastal locations in the northern half of the UK. The far north and west bore the brunt of this storm with 79 knots at South Uist and 91 knots at Lerwick. This produced the biggest January significant wave height for the West of Shetland (12.9m) and the Northern North Sea locations (11.9m). Figure 4 shows a map of significant wave height at its peak of the event. Interrogation of measured datasets in the Northern North Sea region reveal that waves of up to 14m (hs) were measured. Outside of January, and since 1980, six bigger significant wave heights occurred in the model data West of Shetland and three bigger events in the Northern North Sea. Figure 4 Significant wave heights during storm Gertrude Figure 3 Analyses of wind Speeds A more in-depth look at the long-term trends (Figures 5 and 6) reveal that the region is currently experiencing a high frequency of stormy winters. Five of the last six winters (December - February) have had higher average and maximum significant wave heights than much of late 90’s and 2000’s, and bare resemblance to a noticeably stormier period that occurred in the late 1980’s and early 1990’s. Figure 5 December – February mean significant wave heights 1980-2015 Figure 6 December – February maximum significant wave heights 1980-2015