Minimum-time route location is linked to the jet stream Eastbound: New York - London fly in the jet stream Westbound: London - New York avoid the jet stream.

Minimum-time route location islinked to the jet stream

Eastbound: New York - London fly in the jet stream

Westbound: London - New York avoid the jet stream

1Irvine et al., 2013, Meteorological Applications

Winter weather types are characterised by the jet stream

Eastbound Westbound

Irvine et al., 2013, Met. Apps.

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W1. strong zonal jet

W2. Strong tilted jet

W4. Confined jet

Pressure pattern at flight level (black) and jet stream (red). Daily minimum-time routes between London and New York (blue).

FL300 FL340 FL390

W1. Zonal jet

W2. Tilted jet

W4. Confined jet

Eastbound routes Westbound routes

tropopause

Contrail formation regions are linked to the weather pattern

Route time varies accordingto the weather pattern

Jet stream location is related to the North Atlantic Oscillation

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Diagrams from: http://www.ldeo.columbia.edu/res/pi/NAO/

Positive NAOjet stream further north

Negative NAOjet stream further south

Frequency of winter weather patterns

Type Jet stream Frequency  Position Strength (days/season)

W1 zonal strong 17W2 tilted strong 17W3

tilted weak 15

W4 confined strong 15W5 confined weak 26

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