LONG-TERM GOALS

The long-term goals of our research are to understand the nature of the interactions between tropical cyclones and their surroundings, and the impact of these interactions on tropical cyclone intensity. OBJECTIVES The primary objectives are: (i) To evaluate tropical cyclone intensity change during interactions with upper tropospheric troughs, and to develop some rules to govern prediction of such intensity change; and (ii) To study the outbreaks of multiple tropical cyclones in the Western Pacific Ocean to understand what large-scale characteristics are associated with these outbreaks. The first of these is an extension of previous work under ONR support, while the second represents our first concentration on Western Pacific tropical cyclones. APPROACH The first objective has been approached by two types of observational studies using gridded analyses from the European Centre for Medium Range Weather Forecasting (ECMWF): individual case studies and composite studies. The second objective has made use of time filtering of both ECMWF gridded analyses and outgoing longwave radiation (OLR) data