Study of the convergence of low cloudiness by the effect of ocean breeze using the regional climate model

Abstract

This work sought to analyze in high resolution the downscaling of the global model Climate Forecast System Version 2 (CFSv2) by using the regional climate model RegCM-4.9. The precipitation fields were generated in two different domains and spatial resolution with 10 km and 3 km, for August to October 2020. The equatorial region of Northeast Brazil can be characterized by the complex dynamics that encompass atmospheric movements such as the existence of convergence at low levels of convective cloudiness and its diurnal effect on low cloud cover and its influence on evident precipitation. However, for meteorological scales with a daytime circle, the land-ocean breeze effect in the Gulf of Maranhão in this theoretical model of night convergence shows a peak between 6 to 9 am local time. This work seeks to recognize the existence of land-ocean breeze in Alcântara and its influence on the daytime precipitation cycle, its dynamics can influence aerospace activities by increasing convergence and, depending on its intensity, generating more intense rainfall in the coastal region even in the dry period, which corresponds to the most suitable period for the operational activities of the Alcântara Launch Center.

Observational study of breezes using a SODAR wind profiler at the Alcântara Launch Center

“…These measurements, at vertical heights of the order of 200 meters, may be associated with ocean breezes on the coast of the Maranhão state at the Alcântara Launch Center. Correa et al (2022) describe dynamic processes at the mesoscale level, that characterize a coastal region in northeastern Brazil, which can be characterized by a complex response with the existence of different degrees of convergence at low levels of convective cloudiness. Having a well-defined signal in the diurnal time scale, characterizing a formation of low cloud cover and its consequent influence on precipitation, whose signal occurs in the early hours of the morning between 7 and 10 o'clock.…”