Weather Transition Periods in Ghanab

Abstract

The transition periods in Ghana are quite interesting because of the hazards they create to the general public and especially the aviation industry. Strong winds accompany rain storms to rip off roofs of buildings. Dust haze will reduce visibility and affect activities of flight operations. Flight routes and destinations will have to be changed for safety measures. Meteorologists in Ghana have studied the synoptic features that trigger these activities. These features include the ITB (Inter Tropical Boundary), the Equatorial Trough and the nature of airmass affecting the West African sub region. winds that mostly affect the country are of continental in nature and northerly, mostly north easterlies. The direction from which the surface wind is blowing at that time determines the strength or intensity of the hazy condition. It defines the transparency of the atmosphere and it has been realized that when the north easterlies affect the country, visibility reduces drastically but when the airmass is directly northerly, though the atmosphere use to be quite dry but not so dusty as compared to the former. Evidence from satellites, GoogleEarth reveals that the nature of the surface over Niger, which is directly northeast of Ghana, looks quite sandy while directly north of the country, which is Mali, looks a little bit rocky. For these reasons, winds originating or tracking Niger looks dustier than those from Mali. The above listed weather conditions (major rainy season, the minor rainy season and the little dry season) do not apply to the entire country but depends on the geographical location and the season. They all occur simultaneously within a year, so weather forecasting for the country has been based on certain local elements in order to arrive at a very high accuracy. The major technique is the location of the Inter Tropical Boundary (ITB) over the West African sub region for which Ghanaian Weather Forecasters and Meteorologists devised in making predictions easier for the country. Because of the geographical location of the country, it is either affected by a maritime air mass or a continental air mass or both at the same time. This led to the exploration of the ITB, a location on the surface of the earth believed to be the boundary or a position where both dry and moist air masses converge on the West African sub region. Experimentally, the ITB has also been realized to coincide with areas on the surface which has dew point temperature of 15°C. Surface weather charts from ECMWF and NOAA had been the products used by Ghanaian meteorologists most of the time in making their weather predictions. The products have been very helpful and are