Type
Text
Type
Thesis
Advisor
Colle, Brian A. | Chang, Edmund K. M. | French, Michael M.
Date
2017-08-01
Keywords
Atmospheric sciences
Department
Department of Marine and Atmospheric Science.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree
Identifier
http://hdl.handle.net/11401/78190
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
A cyclone relative approach and an ensemble sensitivity analysis (ESA) were applied to explore some of the possible reasons for extratropical cyclone center mean sea level pressure errors. For the cyclone relative approach, data were extracted within a box region and saved every 6 hours. GEFS (Global Ensemble Forecast System) control member and ensemble members forecast data were utilized in this research. Around the cyclone, errors in fields such as mean sea level pressure and precipitation rapidly increase from day 4 to day 5, and the errors of all fields examined are consistent with the overpredicted and underpredicted cyclones. For example, for an overforecast cyclone, it has more intense PV (potential vorticity) at 320K, a stronger temperature gradient on 925hPa, and greater simulated precipitation than observed, while the underpredicted cyclones have the opposite results. The day 3 precipitation errors and 925 hPa temperature gradient errors are relatively large before the cyclone errors develop, thus suggesting that moisture and latent heat and dry dynamics could contribute to cyclogenesis intensity errors. ESA accompanied with cyclone relative approach implies that moisture may contribute to the cyclogenesis error at an initial stage of cyclone development. There are also hints of upstream errors growing and moving in from ESA cases. AA possible explanation for underpredicted cyclones might be that less moisture on the warm side of cyclones leads to a weaker upper tropospheric latent heat release, and hence a less amplified PV field, and a weaker cyclone. In addition, a weaker temperature gradient at 925 hPa could also cause a weaker cyclone. | 77 pages
Recommended Citation
Song, Xinxia, "Application of Cyclone Relative Approach and Ensemble Sensitivity Analysis to Better Understand Extratropical Cyclone Errors in Operational Models and Ensembles" (2017). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3685.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3685