Weather Routing of Ships for the Northern Oceans

1985 ◽  
Vol 38 (02) ◽  
pp. 274-282 ◽  
Author(s):  
R. Motte
Keyword(s):  
North Atlantic ◽  
Weather Forecast ◽  
Great Circle ◽  
Synoptic Situation ◽  
Sea State ◽  
The North ◽  
Weather Routing ◽  
The North Atlantic ◽  
Total Accuracy ◽  
Actual Accuracy

Time and space scales are compared for selected speeds of ships in the North Atlantic and North Pacific oceans. Viability of westbound passages on some northern great circle routes is discussed.There would be no problem in precisely weather routing a vessel across an ocean if it were possible to forecast with total accuracy the actual sea state existing for the duration of a voyage. All mariners are well aware that such an ideal circumstance is not as yet possible. Depending upon the general synoptic situation existing for the period, it is fair to make the assumption that the actual accuracy of a weather forecast deteriorates as time progresses.

scholarly journals Right for the Wrong Reason?: A New Look at the 6 June 1944 D-Day Forecast by a Neutral Swede

2020 ◽  
Vol 101 (7) ◽  
pp. E993-E1006
Author(s):  
Anders Persson
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Weather Forecast ◽  
Synoptic Situation ◽  
Sources Of Information ◽  
The North ◽  
Wrong Reason ◽  
Weather Forecasters ◽  
The North Atlantic ◽  
Favorable Conditions

Abstract There are at least three popular perceptions surrounding the weather forecast for the D-day landing in Normandy, 6 June 1994: 1) that the Allied weather forecasters predicted a crucial break or “window of opportunity” in the unsettled weather prevailing at the time; 2) that the German meteorologists, lacking observations from the North Atlantic, failed to see this break coming and thus the invasion took the Wehrmacht by surprise; and 3) that the American forecasters, guided by a skillful analog system, predicted the favorable conditions several days ahead but got no support from their pessimistic British colleagues. This article will present evidence taken mostly from hitherto rather neglected sources of information, transcripts of the telephone discussions between the Allied forecasters and archived German weather analyses. They show that 1) the synoptic development for the invasion was not particularly well predicted and, if there was a break in the weather, it occurred for reasons other than those predicted; 2) the German forecasters were fairly well informed about the large-scale synoptic situation over most of the North Atlantic, probably thanks to decoded American analyses; and 3) from the viewpoint of a “neutral Swede,” the impression is that the American analog method might not have performed as splendidly as its adherents have claimed, but also not as badly as its critics have alleged. Finally, the D-day forecast, the discussions among the forecasters, and their briefings with the Allied command are interesting not only from a historical perspective, but also as an early and well-documented example of decision-making under meteorological uncertainty.

Some Interim Results of the Study

1982 ◽  
Vol 35 (3) ◽  
pp. 502-516
Author(s):  
R. Monk
Keyword(s):  
North Atlantic ◽  
Weather Forecast ◽  
Air Traffic ◽  
Weather Data ◽  
Weather Forecasts ◽  
Additional Information ◽  
European Cities ◽  
The North ◽  
The North Atlantic ◽  
To Receive

We are still in the process of collecting and developing ways of studying and analysing air traffic routes across the North Atlantic. The results presented in this paper must therefore be recognized as provisional. The data comprise some twelve examples of North Atlantic weather forecasts issued from Bracknell; they are sent to us regularly for the 2nd and 15th day of each month. We have also made arrangements to receive notification from the Heathrow Meteorological Office of any days in which there were significant changes in the weather forecast, so that we can request the additional information from Bracknell. Each set of weather data contains the ‘analysis weather’, that is the best estimate of the actual weather at 1200 GMT, and therefore applicable to the time when aircraft are making westerly departures across the North Atlantic from European cities, and also the weather forecasts issued for 12 and 24 hours before this time.

scholarly journals Sea State Decadal Variability in the North Atlantic: A Review

Climate ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 173
Author(s):  
Antoine Hochet ◽  
Guillaume Dodet ◽  
Fabrice Ardhuin ◽  
Mark Hemer ◽  
Ian Young
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Decadal Variability ◽  
Ocean Waves ◽  
Sea State ◽  
Ship Routing ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Long-term changes of wind-generated ocean waves have important consequences for marine engineering, coastal management, ship routing, and marine spatial planning. It is well-known that the multi-annual variability of wave parameters in the North Atlantic is tightly linked to natural fluctuations of the atmospheric circulation, such as the North Atlantic Oscillation. However, anthropogenic climate change is also expected to influence sea states over the long-term through the modification of atmospheric and ocean circulation and melting of sea ice. Due to the relatively short duration of historical sea state observations and the significant multi-decadal variability in the sea state signal, disentangling the anthropogenic signal from the natural variability is a challenging task. In this article, the literature on inter-annual to multi-decadal variability of sea states in the North Atlantic is reviewed using data from both observations and model reanalysis.

scholarly journals Vince – a case study

2009 ◽  
Vol 2 (1) ◽  
pp. 145-150
Author(s):  
A. Carvalho ◽  
I. Soares ◽  
M. Belo Pereira ◽  
M. Vargas ◽  
N. Moreira ◽  
...  
Keyword(s):  
Satellite Imagery ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Numerical Models ◽  
Radar System ◽  
Sea State ◽  
The North ◽  
The North Atlantic ◽  
Surface Observations

Abstract. Vince was an unusual hurricane that developed over the North Atlantic Ocean in an unexpected area, on October 2005. In this work, the authors analyze its background and genesis over the ocean, making use of satellite imagery and numerical models. The impacts on sea state are investigated both numerically and observationally. Landfall over the Iberian Peninsula is monitored with surface observations and a radar system at Algarve (Portugal).

scholarly journals Observation of Jet Stream Winds during NAWDEX and Characterization of Systematic Meteorological Analysis Errors

2020 ◽  
Vol 148 (7) ◽  
pp. 2889-2907 ◽  
Author(s):  
Andreas Schäfler ◽  
Ben Harvey ◽  
John Methven ◽  
James D. Doyle ◽  
Stephan Rahm ◽  
...  
Keyword(s):  
Wind Speed ◽  
North Atlantic ◽  
Wind Shear ◽  
Forecast Error ◽  
Vertical Wind Shear ◽  
Weather Forecast ◽  
Vertical Wind ◽  
Jet Stream ◽  
The North ◽  
The North Atlantic

Abstract Observations across the North Atlantic jet stream with high vertical resolution are used to explore the structure of the jet stream, including the sharpness of vertical wind shear changes across the tropopause and the wind speed. Data were obtained during the North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX) by an airborne Doppler wind lidar, dropsondes, and a ground-based stratosphere–troposphere radar. During the campaign, small wind speed biases throughout the troposphere and lower stratosphere of only −0.41 and −0.15 m s−1 are found, respectively, in the ECMWF and Met Office analyses and short-term forecasts. However, this study finds large and spatially coherent wind errors up to ±10 m s−1 for individual cases, with the strongest errors occurring above the tropopause in upper-level ridges. ECMWF and Met Office analyses indicate similar spatial structures in wind errors, even though their forecast models and data assimilation schemes differ greatly. The assimilation of operational observational data brings the analyses closer to the independent verifying observations, but it cannot fully compensate for the forecast error. Models tend to underestimate the peak jet stream wind, the vertical wind shear (by a factor of 2–5), and the abruptness of the change in wind shear across the tropopause, which is a major contribution to the meridional potential vorticity gradient. The differences are large enough to influence forecasts of Rossby wave disturbances to the jet stream with an anticipated effect on weather forecast skill even on large scales.

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