East Waving Disturbances in Northeast Brazil: A Case Study Using Numerical Modeling of the Mesoscale

Abstract

From May to June, the Easterly Wave Disturbances (EWD) are one of the main meteorological systems that affect the easternmost of Northeast Brazil (NEB). In this work, the Weather Research and Forecasting (WRF) regional model was used with alternating nudging settings to probe their influence on the simulations of EWDs. The simulations were performed in three kinds: (1) without nudging (WRF-DF), (2) using analysis nudging (WRF-AN), and Spectral-Nudging (WRF-SN). In this context, precipitation and wind data from EWD episodes that passed by the NEB between the 12th and the 14th of June 2019 were studied. The results were compared with ERA-Interim reanalysis and GOES 16 and METEOSAT 10 satellite data. The analysis shows that simulations without nudging better predicted the EWD events' third and fourth waves while WRF-AN simulations better described the spatio-temporal distribution of precipitation. WRF-DF and WRF-SN's results simulations showed little difference. This shows that using the Spectral Nudging technique just above the PBL does not expressively influence the behavior of the winds, or the chosen wave number is not suitable to represent EWDs. ERA-Interim reanalysis and WRF-AN simulations showed similar results. This may be related to the chosen nudging coefficient.

Keywords
EWD; WRF; precipitation