The Houston sea breeze largely controls the transport and dispersal of pollutants during the late summer ozone season. In addition to the familiar sea breeze front, which advances inland from Galveston Bay and the Gulf Coast under light wind conditions, the wind in the Texas coastal plain is also modulated by a larger-scale diurnal wind variation which causes surface winds to rotate in a near-inertial circle.

Through theory and idealized numerical simulations, we show that this wind variations is an inertia-gravity wave forced by the coastal heating contrast and modulated by the nearby presence of the critical latitude of 30N. Under steady-state light wind conditions, the waves propagate nearly horizontally and are reflected by the critical latitude, amplifying the response over water. This apparently contributes to the observed large amplitude of the diurnal response several hundred km offshore.

Certain aspects of the nighttime winds observed by radar profilers disagree with both linear theory and fully three-dimensional modeling with a state-of-the-art mesoscale model. We investigate this disagreement through a hierarchy of two-dimensional model simulations in which we explore the effects of non-linearity, realistic surface heating, background wind, and vertical variations of background stratification. Some implications for nighttime transport of urban pollutants and nighttime maritime convection are considered.