Abstract:
The Pan American Climate Studies Sounding Network has provided data that allowed the behavior of a low-level jet over the Yucatan Peninsula to be analyzed and compared with winds across southeastern Mexico. Composite studies were performed for days when a low-level jet was present at Frontera and Ciudad del Carmen, pilot balloon stations in southeast Mexico. These indicated the presence of a low-level jet on the western coast of the Yucatan Peninsula at 1200 UTC; a jet was not present along the east coast. It is likely that a low-level jet forms over the western part of the peninsula as the trade wind boundary layer flow stabilizes overnight. The morning low-level jet gives way to afternoon sea breezes by 0000 UTC. Observations from theodolite stations on the Pacific coast of southeastern Mexico, separated from the Yucatan Peninsula by the ~2-3 km high Sierra Madre de Chiapas, showed that the wind fluctuations there were not correlated with the winds over the Yucatan as expected. Rather than enhancing the winds at the Pacific coast site of Salina Cruz, stronger easterly trade winds at Frontera and Ciudad del Carmen corresponded to weaker meridional winds at Salina Cruz. Winds at Puerto Madero could not be clearly correlated to wind fluctuations at either Salina Cruz or Frontera and Ciudad del Carmen, even though all three stations are in the same region. NCEP reanalyses captured the general wind flow over this region, but do not show the details of the gap flow and the diurnal variations.
Paper available upon request.