Understanding and Forecasting Zonda Wind (Andean Foehn) in Argentina: A Review

Abstract

This paper focuses on the “state of the art” research of the Argentinian zonda wind at the beginning of 2015. Zonda (similar to foehn) is a strong, warm, very dry wind associated with adiabatic compression upon descending the eastern slopes of the Andes Cordillera in western central Argentina. Particularly, hourly surface meteorological information obtained from the Argentine National Weather Service (Servicio Meteorológico Nacional, SMN) from Mendoza Aero (32?50’S, 68?47’W, 704 m ASL) and San Juan Aero (31?34’S, 68?25’W, 598 m ASL) airport meteorological stations was used. The paper contains a history of zonda research mentioning the principal papers since the 1950s, the characteristics of zonda wind (conceptual model, a classic event, intensities categories) and examples of non-classical episodes. Also zonda dynamics, zonda climatology and forecasting problems are considered. A probabilistic method and the model forecast that are running in operative way are commented. Also the climate impact, air quality and damages caused are mentioned. There has been substantial progress in the understanding of this kind of complex wind during the last years, especially since the last decade, accelerated using different models. This paper has highlighted some of these advances by synthesizing some of the major findings. The probabilistic prediction method developed in the 1980s is still very useful to predict zonda in the cities of San Juan and Mendoza. This as well as the new available tools, such as the eta/PRM and GEM models running operatively (continuously) at PRM (Mendoza Regional Meteorology Program), offered the community the possibility to generate an Early Warning System to warn the population particularly in its severe manifestations. The answer to questions regarding time of onset of the event, place where it will occur first, duration, intensity and offset still poses a great challenge for researchers and forecasters in the region.