Attainment and evaluation of a Zonda wind probability index in Mendoza Argentina and it response to wind durability

NORTE F.; OTERO F.; ARANEO D.

Santiago

Conferencia; 11th meeting of the International Conference on Southern Hemisphere Meteorology and Oceanography; 2015

American Meteorological Society

The aim of this work is to obtain a probability index of surface zonda wind occurrence, using the principal component analysis (PCA) evaluating their ability to identify the zonda wind associated patterns, building an entry matrix with the temperature and dew point temperature anomalies for the standard levels between 850 and 300 hPa. The analysis yielded six significant components, explained 94% of the variance. Thus representing patterns of favorable weather conditions for the development of the phenomenon were obtained. The zonda/no-zonda indicator can be estimated by a logistic multiple regressions dependent to the component loadings, calculable from the T and Td profiles and it depends on the climatological features of the region. The highest correlations between the CP and the index values and non-zonda /zonda were obtained for components 2, 4 and 5. The index showed an efficiency of 74.7%. On the other hand we assess whether the calculated index responds, somehow, to the duration of zonda wind events. Indices values between 0.9 and 1 represent 21.3% chance to be a long event, 27.8% chance to be a short event and a 50.9% chance to be an intermediate event. Similarly, the probability of finding long events for values between 0.8 and 0.9 decreases to 5% and the probability of intermediate events increases, with more than 60%, and short events over 33%.