  The Tropical Easterly Jet (TEJ) is a prominent atmospheric circulation
feature observed during the Asian Summer Monsoon (ASM). The simulation of TEJ
by the Community Atmosphere Model, version 3.1 (CAM-3.1) has been discussed in
detail. Although the simulated TEJ replicates many observed features of the
jet, the jet maximum is located too far to the west when compared to
observation. Orography has minimal impact on the simulated TEJ hence indicating
that latent heating is the crucial parameter. A series of aqua-planet
experiments with increasing complexity was undertaken to understand the reasons
for the extreme westward shift of the TEJ.
  The aqua-planet simulations show that a single heat source in the deep
tropics is inadequate to explain the structure of the observed TEJ. Equatorial
heating is necessary to impart a baroclinic structure and a realistic
meridional structure. Jet zonal wind speeds are directly related to the
magnitude of deep tropical heating. The location of peak zonal wind is
influenced by off-equatorial heating which is closest to it. Hence the presence
of excess rainfall in Saudi Arabia has been shown to be the primary reason for
the extreme westward shift of the TEJ maximum.
