Observed and simulated northern hemisphere intraseasonal circulation anomalies and the influence of model bias
MetadataShow full item record
The ability of an atmospheric general circulation model to simulate the observed primary modes of intraseasonal variability in the Northern Hemisphere upper-tropospheric winds during boreal winter is examined. Rotated empirical orthogonal function analysis is used to determine the primary modes of variability in the Pacific and Atlantic regions. EOFs are computed for both the zonal and meridional wind components. Time-lagged composite analysis is used to examine the temporal evolution of these modes, as well as their relationship to tropical convection. Wave activity flux vectors are used to examine further the characteristics of these intraseasonal modes and their relationship to tropical and extratropical forcing. It is found that the model simulates the extratropically forced modes well but simulates modes associated with tropical heating poorly. The poor tropical simulation is due primarily to the model`s poor representation of the Madden-Julian oscillation (MJO). The model`s inability to produce the MJO-related modes is reflected in the model upper-tropospheric wind field variability being too weak in the subtropical and tropical Indian and Pacific Ocean regions. 47 refs., 16 figs.
The article of record as published may be found at http://dx.doi.org/101175/1520-0493(1996)124<1100:OASNHI>2.0.CO;2
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Downstream Development Associated with the Extratropical Transition of Tropical Cyclones over the Western North Pacific Harr, Patrick A.; Dea, Jonathon M. (2009);The movement of a tropical cyclone into the midlatitudes involves interactions among many complex physical processes over a variety of space and time scales. Furthermore, the extratropical transition (ET) of a tropical ...
Harr, P.A.; Elsberry, R.L. (American Meteorological Society, 1995-05-01);The basic structure of the variability of the large-scale circulations over the tropical western Pacific is investigated with respect to its influence on tropical cyclone characteristics. A vector empirical orthogonal ...
Schwing, F.B; Murphree, T.; Green, P.M. (2002);We introduce the Northern Oscillation Index (NOI), a new index of climate variability based on the difference in sea level pressure (SLP) anomalies at the North Pacific High (NPH) in the northeast Pacific (NEP) and near ...