Land & People
Geography
Ghana is located on West Africa's Gulf of Guinea only a few degrees north of the Equator. Half of the country lies less than 152 meters (500ft) above sea level, and the highest point is 883 meters (2,900ft). The 537 km (334miles) coastline is mostly a low, sandy shore backed by plains and scrub and intersected by several rivers and streams, most of which are navigable only by canoe. A tropical rain forest belt, broken by heavily forested hills and many streams and rivers, extends northward from the shore, near the Cote d'Ivoire frontier. This area, known as the "Ashanti", produces most of the country's cocoa, minerals, and timber. North of this belt, the country varies from 91-396 meters (300-1,300ft) above sea level and is covered by low bush, park-like savannah, and grassy plains.
The climate is tropical. The eastern coastal belt is warm and comparatively dry; the south-west corner, hot and humid; and the north, hot and dry. There are two distinct rainy seasons in the south May-June and August-September; in the north, the rainy seasons tend to merge. A dry, north-easterly wind, the harmattan, blows in January and February. Annual rainfall in the coastal zone averages 83cm (33inches).
Volta Lake, the largest man-made lake in the world, extends from the Akosombo Dam in south-eastern Ghana to the town of Yapei, 520km (325 miles) to the north. The lake generates electricity, provides inland transportation, and is a potentially valuable resource for irrigation and fish farming.
Climate
Ghana's climate, like that of the rest of the Guinea Coast, is determined largely by the interplay of two air masses: a hot, dry continental air mass that forms over the Sahara and a warm, humid maritime tropical air mass that forms over the South Atlantic. Both air masses move toward the equator with their hemispheric winds and meet at the Guinea Coast for several months each year. Continental air moves southward with the northeast trade winds, known in Western Africa as the harmattan, and maritime tropical air moves northward with the southwest trades. The zone where these air masses converge is characterized by seasonal line squall rainfall. The convergence zone itself oscillates north and south, following the seasonal movements of the overhead sun and the thermal equator; it reaches its most northerly position in the central Sahara, about latitude 21° C, in August, and its most southerly position about 7° C, a few miles north of the Ghana coastline, in January. Rains occur when the dominant air mass is maritime tropical, and drought prevails when continental air and the harmattan dominate.
In the savannah country north of the Kwahu Plateau, there are mainly two seasons, a dry season from November to March, with hot days and cool nights under clear skies, and a wet season that reaches its peak in August and September. The mean annual rainfall is between 45 and 50 inches (1,145 and 1,270 millimetres), but there is a marked moisture deficit because of the long, intensely dry season that follows. In the southern forest country, where the annual mean rainfall from north to south has a range of about 50 to 86 inches, there are two rainy seasons-one from April to July and a lesser one from September to November-and two relatively dry periods that occur during the harmattan season, from December to February, and in August, which is a cool, misty month along the coast. In the Accra Plains, anomalously low annual mean rainfall figures vary from 40 inches to less than 30 inches, and the rainfall variability and the vegetation bear close resemblance to conditions in the northern savannah zone.
Temperatures show much more regional uniformity. The annual mean temperature is from 78° to 84° F (26° to 29° C), and the daily range only some 10° to 15° F (6° to 8° C) along the coast, and some 13° to 30° F (7° to 17° C) in the north. Average relative humidity range from nearly 100 percent in the south to 65 percent in the north, although during the harmattan season figures as low as 12 percent have been recorded in the north and around Accra. Enervating conditions produced locally by the combination of high temperatures and high humidity is moderated by altitude in the higher parts and by land and sea breezes along the coast. In general, the hottest months are February and March, just before the rains, and the lowest temperatures occur in January or along the coast in August.
