A synoptic study of west african disturbance lines

The paper gives an account of Disturbance Lines (D/Ls) observed on the charts of the forecasting office of the Ghana Meteorological Department at Accra in 1955. The progress of one of the larger D/Ls is shown to indicate the extensive area affected in some cases. The origins of D/Ls, their movement, distribution, and other characteristics, are described. The importance of the phenomenon in the local weather is shown by the proportion of the monthly rainfall due to D/Ls at four Ghana stations. Emphasis is placed on the nature of the D/L as a disturbance which moves through the atmosphere, transferring convective energy to other forms, notably horizontal kinetic energy, in an ordered manner.