Narrow Results

Atmospheric and oceanic climate factors and conditions play a crucial role in modulating seasonal/annual tropical cyclone activity in the North Atlantic Ocean Basin. In the following, correlations between North Atlantic tropical cyclone activity including frequency of occurrence and pathways are explored, with special emphasis on hurricanes. The value of two-dimensional and three-dimensional data sets representing climate patterns is investigated. Finally, the diagnostic study of historical tropical cyclone and hurricane temporal and spatial variability and relationships to climate factors lead to a statistical prognostic forecast, made in April, 2010, of the 2010 tropical cyclone and hurricane season. This forecast is tested both retrospectively and presently and is shown to be quite accurate. Knowing the probability of the frequency of occurrence, i.e. the numbers of named storms to form in general and the number of hurricanes (NHs) that are likely to form, is important for many societal sectors. However, the reliable forecasts of probable pathways of predicted events, specifically the likely NH land falls along the coastlines of the United States, should have great potential value to emergency planners, the insurance industry, and the public. The forecast provided in this study makes such a prognostication. As the 2010 hurricane season has progressed, an update of the goodness of the forecast is shown to be quite accurate in numbers of named events, hurricanes, major hurricanes (MHs), and landfalls. The mathematical and statistical methodology used in this study, which could be coupled to next generation "empirical modal decomposition," suggests that this may signal a new era in the future of tropical cyclone forecasting, including the reliable prognostication of numbers of events, intensities of events, and the pathways of those events. The ability to reliably predict the probability and location of land falls of these destructive events would be very powerful indeed.

The Community Climate System Model (CCSM3) is the primary model for global climate research in the United States and is supported on a variety of computer systems. We present some of our porting experiences and describe the current performance of the CCSM3 on the Cray X1. We include the status of work in progress on other systems in the Cray product line.

Although the dramatic increase in computational power, a complete description of the Earth's climate by means of solutions of the equations of motion is far from being achieved. Most of the problems arise because the solutions depend on the second order effects of the dynamic and thermodynamic instability processes that plague the system. These instabilities are such that the observed behavior strongly departs from the response of the atmosphere to the forcing associated with the energy input. In illustrating the nature of the problem, we shall discuss the Atmospheric General Circulation, i.e. the circulation obtained by averaging the atmospheric motion along the longitude. We will show, by considering both the observed motion and some theoretical models, that the solution requires the parameterization of the momentum and heat fluxes associated with the baroclinic instability of the full three dimensional field. We will discuss how the parameterizations strongly depend on the detailed nature of the external parameters. As a conclusion, some speculations on the nature of the closure needed for this problem will be offered.