The eastward propagating component of zonal wave one is studied from 39 winters of NCEP reanalyses, each winter of 6 months in length. Phase speeds of ~1-15 m/sec can be resolved with much better statistical significance than in previous studies due to the size of the data set. The 200 hPa zonal wind (u) wave one variance for these phase speeds (corresponding to periods of ~30-90 days) have maxima in: (a) mid-latitudes, (b) near the sub-tropical jet, and (c) in the tropics. The fluctuations are highly coherent from (a) to (b) and (b) to (c), with accompanying 180o phase reversals. The vertical structure of the fluctuations at (a) and (b) shows maxima at upper levels, with small phase shifts. In the tropics, the upper-level / lower-level phase shift is 180o, consistent with the MJO. At 200 hPa, 13oN, the fluctuations are highly coherent with those at the equator at 700 hPa. The results for the Southern Hemisphere are similar. Comparison to previous work will be given. Relationships to theories of long wave baroclinic instability will be discussed, as well as the linkages to the MJO. Implications for the successful simulation of the MJO in GCMs will be presented.
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12th Conference on Atmospheric and Oceanic Fluid Dynamics