Abstract

OTERO, Federico  and  NORTE, Federico A. Classification methods and statistic of Zonda wind in San Juan city. Geoacta [online]. 2015, vol.40, n.1, pp.45-53. ISSN 1852-7744.

This paper intends to evaluate different Objective Classification Methods (OCM) for zonda wind (foehn) events and update the statistics of this phenomenon in the city of San Juan. First, a classification was performed according to the "three point method", where analyze temporal changes in wind speed and direction, temperature and humidity to diagnose the presence of zonda. This classification was used as a reference for assessing the classification ability for other objective methods, which help us to understand the most important variables that provide a physical basis to define the Zonda wind occurrence at San Juan station. Following the classification methodologies by other authors, the most appropriate variables were selected, being a combination of the speed and direction of wind and temperature anomalies and relative humidity. Three OCM are proposed; The Maximum Temperature Method of the (MTM), including daily maximum temperature, monthly average maximum temperature and minimum dew point temperature for the same day variables; the Daily anomalies Method (DM), which has as variables the daily temperature and dew point temperature anomalies and finally, the Seasonal anomalies Method (SM), with seasonal temperature and dew point temperature anomalies. All methods were able to identify many of the Zonda wind events in San Juan. Finally, Zonda wind climatology where addressed for the different proposed methods, diurnal and annual cycle, onset, offset and the average duration of the events took place in this analysis.

Keywords : Foehn; Zonda wind; Objective Classification Method diagnosis; Statistics.

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