An altered atmospheric circulation regime during Last Glacial Maximum Camille Li, Aaron Donohoe Davi

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An altered atmospheric circulation regime during
Last Glacial MaximumCamille Li, Aaron
DonohoeDavid BattistiUniversity of Washington
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Coupled model
winter jet and storminess
poleward heat flux 850mb (Km/s)
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Coupled model
winter jet and storminess

• Compared to todays climate, the ice age climate
  simulated by the coupled model exhibits
• a stronger, steadier Atlantic jet
• reduced storminess

poleward heat flux 850mb (Km/s)
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Coupled model
winter jet and storminess
poleward heat flux 850mb (Km/s)
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Coupled model
winter jet and storminess
Laurentide elevation (km)
ICE-5G
ICE-4G
poleward heat flux 850mb (Km/s)
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CAM Model Run with ICE 5G Vertically Integrated
JFM Eddy Heat Transport
LGM
Modern
K m/s
LGM- Modern
Contours are the jet speed at 400 hPa
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Possible Causes of Reduced LGM Atlantic Storminess
I.) Narrow LGM jet inhibits storm growth
Jet Speed Cross Sections LGM jet is narrow
NOT Strong enough effect
II.) High LGM Static stability inhibits storm
growth
Strong LGM Baroclinicity still predicts stronger
storm Growth
III.) LGM Storms are not seeded efficiently
LGM Modern
50
Magnitude Geopotential Height
Perturbation (meters)
0
0
4
8
12
16
Days Since Storm Entered Atlantic Domain