Stewart, M. L. (2007).
Cyclogenesis and Tropical Transition in Frontal Zones. Master's thesis, Florida State University, Tallahassee, FL.
Abstract: Tropical cyclones can form from many different precursors, including baroclinic systems. The process of an extratropical system evolving into a warm core tropical cyclone is defined by Davis and Bosart (2004) as a Tropical Transition (TT) with further classification of systems into Weak Extratropical Cylclones (WEC) and Strong Extratropical Cyclones (SEC). It is difficult to predict which systems will make the transition and which will not, but the description of a common type of TT occurring along a front will aid forecasters in identifying systems that might undergo TT. A wind speed and SST relationship thought to be necessary for this type of transition is discussed. QuikSCAT and other satellite data are used to locate TT cases forming along fronts and track their transformation into tropical systems. Frontal TT is identified as a subset of SEC TT and the evolution from a frontal wave to a tropical system is described in five stages. A frontal wave with stronger northerly wind and weaker southerly wind is the first stage in the frontal cyclogenesis. As the extratropical cyclogenesis continues in the next two stages, bent back warm front stage and instant occlusion stage, the warmer air of the bent back front becomes surrounded by cooler air . Next, in the subtropical stage the latent heat release energy from the ocean surface begins ascent and forms a shallow warm core. As the energy from surface heat fluxes translates to convection within the system, the warm core extends further into the upper levels of the atmosphere in the final, tropical stage of TT. Model data from MM5 simulations of three storms, Noel (2001), Peter (2003) and Gaston (2004) are analyzed to illustrate the five stages of frontal TT. Noel is found to have the most baroclinic origin of the three and Gaston the least.
Smith, R. A. (2007).
Trends in Maximum and Minimum Temperature Deciles in Select Regions of the United States. Master's thesis, Florida State University, Tallahassee, FL.
Abstract: Daily maximum and minimum temperature data from 758 COOP stations in nineteen states are used to create temperature decile maps. All stations used contain records from 1948 through 2004 and could not be missing more than 5 consecutive years of data. Missing data are replaced using a multiple linear regression technique from surrounding stations. For each station, the maximum and minimum temperatures are first sorted in ascending order for every two years (to reduce annual variability) and divided into ten equal parts (or deciles). The first decile represents the coldest temperatures, and the last decile contains the warmest temperatures. Patterns and trends in these deciles can be examined for the 57-year period. A linear least-squares regression method is used to calculate best-fit lines for each decile to determine the long-term trends at each station. Significant warming or cooling is determined using the Student's t-test, and bootstrapping the decile data will further examine the validity of significance. Two stations are closely examined. Apalachicola, Florida shows significant warming in its maximum deciles and significant cooling in its minimum deciles. The maximum deciles seem to be affected by some localized change. The minimum deciles are discontinuous, and the trends are a result of a minor station move. Columbus, Georgia has experienced significant warming in its minimum deciles, and this appears to be the result of an urban heat-island effect. The discontinuities seen in the Apalachicola case study illustrate the need for a quality control method. This method will eliminate stations from the regional analysis that experience large changes in the ten-year standard deviations within their time series. The regional analysis shows that most of the region is dominated by significant cooling in the maximum deciles and significant warming in the minimum deciles, with more variability in the lower deciles. Field significance testing is performed on subregions (based on USGS 2000 land cover data) and supports the findings from the regional analysis; it also isolates regions, such as the Florida peninsula and the Maryland/Delaware region, that appear to be affected by more local forcings.
Brolley, J. M., O'Brien, J. J., Schoof, J., & Zierden, D. (2007). Experimental drought threat forecast for Florida.
Agricultural and Forest Meteorology, 145(1-2), 84–96.
Peng, M. S., Maue, R. N., Reynolds, C. A., & Langland, R. H. (2007). Hurricanes Ivan, Jeanne, Karl (2004) and mid-latitude trough interactions.
Meteorol. Atmos. Phys., 97(1-4), 221–237.
Lim, Y. - K., & Kim, K. - Y. (2007). ENSO Impact on the Space-Time Evolution of the Regional Asian Summer Monsoons.
J. Climate, 20(11), 2397–2415.
Smith, S. R., Brolley, J., O'Brien, J. J., & Tartaglione, C. A. (2007). ENSO's Impact on Regional U.S. Hurricane Activity.
J. Climate, 20(7), 1404–1414.
Gierach, M. M., Bourassa, M. A., Cunningham, P., O'Brien, J. J., & Reasor, P. D. (2007). Vorticity-Based Detection of Tropical Cyclogenesis.
J. Appl. Meteor. Climatol., 46(8), 1214–1229.
Hart, R. E., Maue, R. N., & Watson, M. C. (2007). Estimating Local Memory of Tropical Cyclones through MPI Anomaly Evolution.
Mon. Wea. Rev., 135(12), 3990–4005.
Lim, Y. - K., Shin, D. W., Cocke, S., LaRow, T. E., Schoof, J. T., O'Brien, J. J., et al. (2007). Dynamically and statistically downscaled seasonal simulations of maximum surface air temperature over the southeastern United States.
J. Geophys. Res., 112(D24).
Xu, X., Chassignet, E. P., Price, J. F., Özgökmen, T. M., & Peters, H. (2007). A regional modeling study of the entraining Mediterranean outflow.
J. Geophys. Res., 112(C12).