The oscillatory effect of chemical constituents, dynamics, barometric, and thermodynamics on weather over Accra, and Bissau

Abstract

A sharp contrast in atmospheric weather conditions prevailed over Accra and Bissau and that led to the oscillatory nature of weather conditions between the two cities. During the latter part of July 2022, Bissau experienced persistent and continuous rains whilst Accra remained fair and dry. It was realized that when an air parcel rises, low-pressure system is created at the surface but when the air parcel sinks, high pressure forms. Pressures were predominantly high over Accra and low over Bissau during that time. Models from CAMS were used to study chemical compositions to determine the concentration and effect of Sulphur Dioxide (SO2) over the two cities. Wind behavior over various levels in the atmosphere was considered using model products from ECMWF, satellite imagery from EUMETSAT, and t-phi gram from the Air Resources Laboratory of NOAA to study the thermodynamics of the skies. METAR, hourly observations made by the National Meteorological Offices from the two cities were retrieved from the AADS and Ogimet to study the barometric nature during the period. Results show that the atmosphere over Bissau had been less polluted as compared to that of Accra which makes Bissau to be persistently cloudy. Atmospheric chemical constituents would have to compete for moisture if the concentration is high and does not support the sustenance of massive clouds capable of producing rain. It has been realized that the development of anticyclone, an anticlockwise circulation at the 200 hPa level contributed to the cloud sustenance over Bissau during that time.