HR: 1340h
AN: A43B-1151    [Abstracts]
TI: Annular Modes and the Poleward Movement of Subtropical Dry Zones
AU: * Previdi, M
EM: mprevidi@ldeo.columbia.edu
AF: Columbia University, 61 Route 9W, Palisades, NY 10964, United States
AU: Liepert, B G
EM: liepert@ldeo.columbia.edu
AF: Columbia University, 61 Route 9W, Palisades, NY 10964, United States
AB: Projections of twenty-first century climate from the latest state-of-the-art climate models consistently call for a poleward expansion of the subtropical dry zones (SDZ) in response to increasing levels of atmospheric greenhouse gases. We find that approximately half of the model-simulated SDZ expansion during the next hundred years can be explained by positive trends in the Northern Hemisphere and Southern Hemisphere annular modes (NAM and SAM), implying a close connection between changes in the tropical and extratropical atmospheric circulation. The link between NAM and SAM variability and the SDZ expansion suggests that future changes in the hydrologic cycle are likely to be strongly influenced by atmospheric dynamics.
DE: 1610 Atmosphere (0315, 0325)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1626 Global climate models (3337, 4928)
DE: 1655 Water cycles (1836)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting