An Analysis of TAFB's Dvorak Estimates

TAFB routinely provides satellite-based Dvorak estimates of tropical cyclone (TC) intensity for TCs that occur in the North Atlantic and East Pacific basins. The goal of this study is to compare TAFB Dvorak estimates to the NHC best track intensity during times when aircraft reconnaissance is available, in order to quantify typical intensity uncertainty when intensity is determined using satellite estimates only. A subjective re-evaluation of TAFB’s 2023 Atlantic and East Pacific basin Dvorak estimates was performed after the season. A few of the classifications in this post-storm assessment needed to be adjusted upward or downward in T-number based upon a more rigorous application of the Dvorak approach and rules. This evaluation resulted in a recommended correction of 1.0 or more T-numbers to 1% of the CI numbers, 0.5 T-number to 12% of the CI numbers, and no changes to 87% of the CI numbers. The original and re-evaluated TAFB Dvorak datasets for 2023 are compared to the NHC best track intensity, only during times when aircraft reconnaissance was available. It is hypothesized that the average intensity difference between the re-evaluated TAFB CI number and the NHC best track intensity for these cases will be similar to the values provided in the “satellite only” section of Table 2 of Landsea and Franklin (2013), which is ~11-12 kt for tropical storms through Category 2 hurricanes, and 13-14 kt for major hurricanes.

Reference: Landsea, C. W., and J. L. Franklin, 2013: Atlantic Hurricane Database Uncertainty and Presentation of a New Database Format. Monthly Weather Review, 141, 3576-3592.