A diagnostic study of rapidly developing cyclones using surface-based Q vectors
By: David W. Titley
Publisher: Naval Postgraduate School;c1991.
Published: 1991
Place of publication: Monterey, Calif
Language: eng
Number of pages: 122
Description: Accurate short-term (0-6 h) forecasts of rapid cyclogenesis are important to both civilian and military maritime interests. Because upper-air observations over the ocean are sparse, the relatively plentiful surface synoptic data must be used for diagnostic analysis. Surface pressure and temperature data for two Intensive Observation Periods (IOPs) that occurred during the Experiment on Rapidly Intensifying Cyclones over the Atlantic (ERICA) are objectively analyzed and Q vectors--a measure of the low-level ageostrophic flow required to restore geostrophic balance--are calculated. Areas of Q vector convergence, which imply upward vertical motion, were compared to satellite imagery and to the future 3-h and 6-h pressure tendencies. When the storms were intensifying most rapidly, satellite imagery showed cold-topped stratiform clouds over areas of Q vector convergence. Areas of strong Q vector convergence (divergence) showed significant (95% confidence level) pressure falls (rises) 3 h and 6 h in the future. Surface Q vectors are shown to have qualitative value in short-range forecasts of the location of the storm, but do not forecast storm intensity. The surface Q vector interpretations are less useful near landmasses, as the surface temperature field becomes less representative of the mean tropospheric temperature. ERICA, Q Vectors, Vertical motion, Rapid cyclogenesis, Marine cyclogenesis.
Notes: Thesis advisor(s): Wendell A. Nuss ; Second Reader: Elsberry, Russell L.

Author(s) subject terms: ERICA, Q vectors, vertical motion, raped cyclogenesis, marine cyclogenesis.

DTIC Descriptors: Weather Forecasting, Ocean Surface, Cyclogenesis, Air Flow, Atmospheric Temperature, Intensity, Motion, Theses, Meteorological Satellites, Pressure, Balance, Storms, Low Level, Convergence, Flow, Value, Mean, Barometric Pressure, Atlantic Ocean, Air Water Interactions, Surface Temperature, Geostrophic Wind, Cyclones, Stratus Clouds, Observation, Air, Clouds, Temperature

DTIC Identifiers:  Erica, Q Vectors, Vertical Motion, Rapid Cyclogenesis, Marine Cyclogenesis

"June 1991."

Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, June 1991.

Bibliography: p. 116-120.

"Approved for public release; distribution is unlimited"-Cover.

Also available online.

Mode of access: World Wide Web.

System requirements: Adobe Acrobat reader.

US Navy (USN) author.