HR: 10:50h
AN: A12C-03    [Abstracts]
TI: Characteristics of the Atlantic Storm-track Eddy Activity and its Relation With the North Atlantic Oscillation
AU: * Riviere, G
EM: griviere@princeton.edu
AF: Atmospheric and Oceanic Sciences Program, Princeton University, Forrestal Campus, US Route 1, Princeton, NJ 08542
AU: Orlanski, I
EM: Isidoro.Orlanski@noaa.gov
AF: Geophysical Fluid Dynamics Laboratory / NOAA, Princeton University, Forrestal Campus, US Route 1, Princeton, NJ 08542
AB: Our study focuses on feedbacks of the high-frequency eddy activity onto the quasi-stationary circulation, particularly with regard to the North Atlantic Oscillation (NAO). The methodology consists in analyzing observations from NCEP reanalysis data and sensitivity runs from a high resolution non hydrostatic regional model. Consistent with recent studies from Orlanski (2003) and Benedict et al. (2004), results show that the jet displacement characteristic of the NAO phenomenon depends strongly on the dynamics of the high-frequency synoptic-scale waves and the way they break. Positive and negative phases of the NAO are closely related to anticyclonic and cyclonic wave breaking respectively. The original aspect of our work is to show that wave breaking over the Atlantic is strongly sensitive to the spatial and temporal characteristics of the upper-level waves coming from the Eastern Pacific and North America. Another crucial factor is the amount of eddy energy generation in the low levels which is directly related to the surface moisture fluxes. Depending on the ratio between the low-level energy and the upper-level one, waves can break cyclonically or anticyclonically.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
DE: 3364 Synoptic-scale meteorology
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005