On the Observed Diurnal Oscillation of the Somali Jet

Abstract

The time mean and diurnal oscillation of the Somali jet are examined, using as a data base a high-resolution time series of pilot balloon soundings for two sites in northeast Africa. The diurnal mode is found to contain a significant amount of the total amplitude of the jet. In association with this oscillation, the level of maximum wind varies considerably during the course of a day. A multi-cored jet structure is observed during the afternoon. Other interesting structural variations of the jet are discussed. Hypotheses are ventured to provide explanations for the observed behavior of this low-level jet.