Forecasting Zonda wind occurrence with ERA5 Reanalysis

OTERO, FEDERICO; ARANEO, DIEGO

Buenos Aires

Congreso; CONGREMET XIV; 2022

Centro Argentino de Meteorólogos

The Zonda winds is a strong, warm, and very dry wind associated with adiabatic compression upon descending over the eastern slopes of the Andes range. The synoptic conditions leading to these, sometimes severe, downslope winds commonly vary between mountain ranges in different parts of the world. However, there are some common conditions favoring foehn winds: A cross-barrier pressure gradient, either caused by different air masses or by the dynamic pressure of the incoming flow; crest-level flow with a wind component perpendicular to the crest and a stable stratification of the air masses upstream. In the present work, Principal Component Analysis is applied to the ERA5 reanalysis data in order to discriminate between Zonda and non-Zonda events using the synoptic fingerprint. Also, a coupled model using reanalysis data and vertical sounding on both sides of the Andes is performed, a new prediction model for Zonda occurrence is found.