Variability in global-scale circulations and their impacts on Atlantic tropical cyclone activity

Download
Author
Rosencrans, Matthew J.
Date
2006-06Advisor
Harr, Patrick
Murphree, Tom
Metadata
Show full item recordAbstract
evel relative vorticity, a decrease in westerly vertical wind shear, and increased convection in the West African monsoon (WAM). The second and third modes of an empirical orthogonal function (EOF) analysis of the 700-hPa height anomalies identify a distinct Rossby-wave pattern. Significant variability in the Southern Hemisphere mid-latitude circulations is related to the two EOF modes and to equatorward Rossby-wave dispersion. Formation of a large cyclonic anomaly over the southeast Pacific, west of Chile, is related to equatorward propagation of a Rossby-like wave across South America, toward the equatorial Atlantic. The cyclonic anomaly precedes an increase in WAM convection by an average of two days, which then precedes westerly wind anomalies over the equatorial North Atlantic by several days. Tropical cyclone formation is found to be enhanced when the increased equatorial westerly anomalies coincide with reduced vertical wind shear, which is related to Northern Hemisphere midlatitude circulations
Collections
Related items
Showing items related by title, author, creator and subject.
-
An Explanation for the Curvature of the Atlantic Jet past the Strait of Gibraltar
Viúdez, Álvaro (American Meteorological Society, 1997-08);A consistent explanation for the anticyclonic curvature of the Atlantic jet as it passes through the Strait of Gibraltar and flows into the Mediterranean Sea (eastern side of the strait) is provided. The anticyclonic ... -
An assessment of NOGAPS performance in the prediction of tropical Atlantic circulation formation
Dorics, Theodore G. (Monterey, California. Naval Postgraduate School, 2002-06);The Navy requirement for 5-day tropical cyclone track guidance necessitates an assessment of the Navy Operational Global Atmospheric Prediction System (NOGAPS) in forecasting tropical cyclone formation. The Tropical Cyclone ... -
An evaluation of 700 mb aircraft reconnaissance data for selected northwest Pacific tropical cyclones
Dunnavan, George Milton (Monterey, California. Naval Postgraduate School, 1983-09);The 700 mb aircraft reconnaissance data for 25 selected northwest Pacific tropical cyclones were analyzed and compared with similar data for Atlantic tropical cyclones. Correlations of observed winds and winds calculated ...