Tropical Cyclone Predictability
Abstract
LONG-TERM GOALS. I have three closely related long-term goals. My first two goals are to estimate the so-called inherent, or intrinsic, lower limits of predictability for tropical cyclone (TC) forecast track and forecast intensity errors out to 72 hours ahead. My third goal is to develop and apply techniques to enable these inherent limits to be approached in practice and ultimately for transitioning. OBJECTIVES. My scientific objectives are to estimate the so-called intrinsic limits of predictability of tropical cyclone mean forecast position errors in the first instance, and of tropical cyclone intensity errors in the second part of the program. I am using several techniques including Monte Carlo ensemble approaches, procedures adapted from non-linear systems analysis, and optimal combinations of forecasts. I have developed all of these schemes under ONR research grant support. The intrinsic limits of predictability of TCs exist because the equations governing the behavior of all atmospheric systems including TCs are deterministically chaotic. As such, any errors in the initial conditions and/or model formulation lead to error growth that eventually reduce the skill of the forecasts to zero. These intrinsic limits must be compared with the results that are currently being obtained in practice with state-of-the-art real-time NWP models. The size of the disparity between the inherent errors and those being attained in practice represents the gains in predictive skill that are still achievable. It is of fundamental importance to have some idea of how large the gap is between that being obtained and the ultimately achievable in order to justify the continued allocation of resources to the TC forecasting problem. The third research objective is devoted to closing this gap between the intrinsic limits and those achievable in practice.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1999
- Accession Number
- ADA630143
Entities
People
- Lance M. Leslie
Organizations
- University of New South Wales