NOAA'S Hurricane Intensity Forecasting Experiment: A Progress Report

Abstract

An update of the progress achieved as part of the NOAA Intensity Forecasting Experiment (IFEX) is provided. Included is a brief summary of the noteworthy aircraft missions flown in the years since 2005, the first year IFEX flights occurred, as well as a description of the research and development activities that directly address the three primary IFEX goals: 1) collect observations that span the tropical cyclone (TC) life cycle in a variety of environments for model initialization and evaluation; 2) develop and refine measurement strategies and technologies that provide improved real-time monitoring of TC intensity, structure, and environment; and 3) improve the understanding of physical processes important in intensity change for a TC at all stages of its life cycle. Such activities include the real-time analysis and transmission of Doppler radar measurements; numerical model and data assimilation advancements; characterization of tropical cyclone composite structure across multiple scales, from vortex scale to turbulence scale; improvements in statistical prediction of rapid intensification; and studies specifically targeting tropical cyclogenesis, extratropical transition, and the impact of environmental humidity on TC structure and evolution. While progress in TC intensity forecasting remains challenging, the activities described here provide some hope for improvement.

A Long-Term, High-Quality, High-Vertical-Resolution GPS Dropsonde Dataset for Hurricane and Other Studies

“…Understanding of the HBL structure becomes increasingly important as efforts have been made toward developing high-resolution numerical models in order to improve the hurricaneintensity forecast (e.g., Gopalakrishnan et al 2013;Rogers et al 2013). However, the HBL has been the least observed part of a storm until now, especially its turbulence structure (Black et al 2007;Zhang et al 2008;Zhang 2010).…”

A Novel Multiscale Intensity Metric for Evaluation of Tropical Cyclone Intensity Forecasts

“…The nominal grid resolution that is currently used in most models, including some global models, would be sufficient to resolve V 0 1 V 1 for most TCs, because the minimum resolution required for representing this component would be equal to RMW. Observation-based studies have shown that RMW is larger than 20 km for a large majority of the observed TCs (Uhlhorn et al 2013;Rogers et al 2013a). Having the sufficient nominal resolution does not imply that discretization in the model is necessarily adequate for resolving the processes that govern the evolution of the low-wavenumber intensity.…”

“…Observation-based values of the low-wavenumber intensity could be obtained from SFMR measurements (Uhlhorn et al 2007) as reported by operational and research aircraft reconnaissance in the Atlantic basin during the hurricane season (Aberson 2010;Rogers et al 2013b). Although aircraft reconnaissance data are available for only about 30% of the Atlantic basin TCs (Rappaport et al 2009), the retrospective SFMR data since 1998 include a significant number of diverse TC cases (Table 1).…”

Extracting hurricane eye morphology from spaceborne SAR images using morphological analysis

“…This information is critical for determining the hurricane wavenumber or scale category, from the most devastating Category 5 to the weakest Category 1. The intensity values, in evaluating the destructive effect of hurricane event, are represented in 5-knot (kt) increments at landfall based on Dvorak enhanced infrared (EIR) hurricane techniques and hurricane intensity estimation (HIE) algorithm (Dvorak, 1984;Goodman et al, 2012), and SaffirSimpson Hurricane Wind Scale (Rogers et al, 2013). The unit 'knot' is used to avoid the ambiguity if strength of hurricanes is estimated in mph and km/h, since both metrics have been utilized to define the category or intensity of hurricanes in historical records and may be used for future hurricanes.…”