Weak interaction in the African Easterly JetA. Lenouo1, F. Nkankam Kamga1, and E. Yepdjuo21Atmospheric Sciences Lab. Dept. of Physics, Univ. of Yaounde I, Cameroon P.O. Box 812 Yaoundé, Cameroon, Africa
2EAMAC, P.O. Box 746, Niamey, Niger, Africa
Abstract. Low-frequency, African Easterlies Waves (AEW) are examined as
disturbances embedded in the mid-tropospheric easterly jet of the African
low troposphere. The solution to the nonlinear vorticity equation relevant
to the description of waves is sought in the form of triplet waves. The
latest suggest a unified method to determine their kinetics characteristic
and to explain the mechanism of energy exchange between their different
modes. The period of energy interaction between different modes of the
global wave is equal to 3.5 days when the wave packet is moving with a group
velocity dependent on the mean basic flow. The effects of nonlinearity are
also identified, and it is noted that the horizontal shears of mean flow, as
well as the temporal variation of the amplitude wave functions, are the
controlling factors.
Keywords. Meteorology and atmospheric dynamics
(Synoptic-scale meteorology; Tropical meteorology; Waves
and tides)
Full Article (PDF, 564 KB)
Citation: Lenouo, A., Nkankam Kamga, F., and Yepdjuo, E.: Weak interaction in the African Easterly Jet, Ann. Geophys., 23, 1637-1643, 2005. Bibtex EndNote Reference Manager