Tuning of a thunderstorm index for north-eastern Italy

✍ Scribed by Alberto Dalla Fontana

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 368 KB
• Volume: 15
• Category: Article
• ISSN: 1350-4827
• DOI: 10.1002/met.90

✦ Synopsis

Abstract

In the present study the KO index (KOI) is adapted to the climatology of thunderstorms of north‐eastern Italy. A large data set of events falling into the summer months June, July and August of the years 2003–2007 was collected using imagery from the C‐band radar located in Teolo in the north‐eastern Italian region Veneto, and soundings from the Udine station, located 100 km north‐east of the radar. Three methods were evaluated in order to identify the best use of the KOI as a thunderstorm predictor, i.e. based on (1) maximization of the True Skill Score (TSS), (2) frequency distributions, and (3) a probabilistic approach. The first two methods yield the best use of the KOI for categorical (yes/no) forecasts. The third method defines a forecast probability for each value of the KOI. The forecast probabilities were partially corrected for the negative bias found on a reliability diagram. Resolution has been discussed on a Relative Operating Characteristic (ROC) diagram and compared with the TSS. A more reliable evaluation of the scores could be achieved using an independent data set, which is presently not available. Recommendations are given for an effective use of the findings in the forecasting activity. Copyright © 2008 Royal Meteorological Society