An Evaluation of Advanced Dvorak Technique-Derived Intensity Estimate Errors and Biases During the Extratropical Transition of Tropical Cyclones
However, observations of maximum intensity during ET, whether over land or over water, are virtually non-existent. Consequently, while DT and ADT intensity estimates appear to be less reliable and weak-biased during ET, the precise magnitude(s) and temporal evolution(s) of these biases are unknown. To address this issue and motivate research into means by which the ADT's performance during ET may be improved, we utilize synthetic satellite imagery obtained from numerical simulations of thirty representative North Atlantic Ocean ET events between 2000 and 2012 to quantify ADT-derived intensity estimate biases during ET.
Hourly time series of minimum sea level pressure (hPa) and maximum sustained surface wind speed (kt) obtained from each numerical simulation serve as the "observed" intensity estimate for each event. ADT intensity estimates are obtained from synthetic satellite imagery. This approach allows for an internally-consistent comparison between simulated ("truth") and ADT-estimated intensity to be obtained. The performance of the ADT is evaluated by comparing the ADT-derived, synthetic satellite imagery-based intensity estimate to the model-derived maximum sustained surface wind and minimum sea level pressure. Results of this evaluation, including preliminary insight into the sensitivity of research findings to the specific numerical model configuration utilized, will be presented. Extensions of the results to the development of a new Advanced Dvorak Technique "scene type" specific to ET will be discussed.