Publication Date:
2014-08-19
Description:
A data-driven approach to the classification of hydrometeors from measurements collected with polarimetric weather radars is proposed. In a first step, the optimal number nopt of hydrometeor classes that can be reliably identified from a large set of polarimetric data is determined. This is done by means of an unsupervised clustering technique guided by criteria related both to data similarity and to spatial smoothness of the classified images. In a second step, the nopt clusters are assigned to the appropriate hydrometeor class by means of human interpretation and comparisons with the output of other classification techniques. The main innovation in the proposed method is the unsupervised part: the hydrometeor classes are not defined a-priori, but they are learned from data. The proposed approach is applied to data collected by an X-band polarimetric weather radar during two field campaigns (totalling about 3000 h of precipitation). Seven hydrometeor classes have been found in the data set and they have been associated to drizzle (DZ), light rain (LR), heavy rain (HR), melting snow (MS), ice crystals/small aggregates (CR), aggregates (AG), rimed particles (RI).
Electronic ISSN:
1867-8610
Topics:
Geosciences
Permalink