Wind profile and near-surface atmospheric stability at the Alcântara Launch Center

Wind and atmospheric stability are fundamental for aerospace research and development activities at the Alcântara Launch Center, situated in the Maranhao Brazilian state. The physical processes related to these meteorological parameters during the dry season are well known. However, there is still gap concerning the rainy season. The data obtained in the anemometric tower are here studied considering vertical profiles of wind and temperature, and the Richardson bulk number. The mechanical characteristics showed weaker vertical gradient during the daytime-nighttime transition. A primary reason of that behaviour is the sea breeze from 60 m height of the tower. Those near-surface winds are more intense at night in the rainy season. As expected, the surface layer tends to be statically neutral throughout the daytime cycle in the dry season. Meanwhile, this stability classification was seen more frequently at the nighttime in the rainy season. Rainfall events along wet months were typically nocturnal. The deeper convective cells and its derived downdrafts help to understand this behavior. Due to -40% precipitation anomaly reported in this rainy season, these results may have been a direct response to this condition. In future studies, turbulent measurements are required to investigate how the thermodynamic and mechanical pertubations interacts with the rainfall stability patterns during the wet season.