Dvorak Technique - Benefits and Disadvantages

Benefits and Disadvantages

The most significant benefit of the use of the technique is that it has provided a more complete history of tropical cyclone intensity in areas where aircraft reconnaissance is neither possible nor routinely available. Intensity estimates of maximum sustained wind are currently within 5 miles per hour (8.0 km/h) of what aircraft are able to measure half of the time, though the assignment of intensity of systems with strengths between moderate tropical-storm force (60 miles per hour (97 km/h)) and weak hurricane- or typhoon-force (100 miles per hour (160 km/h)) is the least certain. Its overall precision has not always been true, as refinements in the technique led to intensity changes between 1972 and 1977 of up to 20 miles per hour (32 km/h). The method is internally consistent in that it constrains rapid increases or decreases in tropical cyclone intensity. Some tropical cyclones fluctuate in strength more than the 2.5 T numbers per day limit allowed by the rule, which can work to the technique's disadvantage and has led to occasional abandonment of the constraints since the 1980's. Systems with small eyes near the limb, or edge, of a satellite image can be biased too weakly using the technique, which can be resolved through use of polar-orbiting satellite imagery. Subtropical cyclone intensity cannot be determined using Dvorak, which led to the development of the Hebert-Poteat technique in 1975. Cyclones undergoing extratropical transition, losing their thunderstorm activity, see their intensities underestimated using the Dvorak technique. This led to the development of the Miller and Lander extratropical transition technique which can be used under these circumstances.