Confiabilidade do Global Forecast System Operacional e uma Implementação Local do WAVEWATCH III durante um Ciclone Explosivo na América do Sul em junho de 2020

Abstract

A cyclone occurred off the southern Brazilian coast between 30/06/2020 and 01/07/2020, moving eastwards from land towards offshore. The system was registered in numerical models and in-situ observations (buoy and ship) from the day it started until dissipated. The goal of this work is to use the data collected during this extreme environmental condition in a statistical comparison with the atmospheric operational model Global Forecast System (GFS) and a local implementation of the WAVEWATCH III (WW3) wave model, which used the GFS as one of the inputs, to understand the limitations of these models. Initially, the results showed that the system near the southern Brazilian coast was a strong explosive cyclone according to the Sanders and Gyakum (1980) classification. We found that the GFS and WW3 models exhibited greater errors when compared with the buoy data during the 48 h period of explosive weather conditions, while for the GFS model, the greatest errors around the ship occurred after that period. The WW3 errors may be explained by the difference between the buoy and WW3 gridpoint depth and the GFS errors at this location.

Keywords
explosive cyclones; numerical operational weather models; GFS; WW3