High-resolution modeling of the Cape Canaveral area land-water circulations and associated features

The Advanced Regional Prediction System is used to perform a three-dimensio nal numerical simulation of land-water circulations near Cape Canaveral, Fl orida. Three two-way nested grids having spacings of 1.6, 0.4, and 0.1 km a re employed. Results show that the structures of both the sea and river bre ezes compare well with observation and theory. Horizontal convective rolls (HCRs), Kelvin-Helmholtz instability (KHI), and their interactions with the sea and river breezes also are investigated. H CRs form over the heated land surface at periodic intervals. The HCRs have two preferred spatial scales: large and small. Inclusion of both the large and small HCRs yields aspect ratios that are smaller than most previous obs ervations. However, when considering only the larger HCRs, agreement is bet ter. The smaller HCRs eventually dissipate or merge with their larger HCR c ounterparts. These mergers intensify the vertical motion within the larger circulations. The HCRs are observed to tilt upward in advance of the Indian River breeze (IRB), and then advect over and behind the land-water circulation. There is evidence that an HCR advects 2.5 km behind the surface front. The orientat ion of the IRE causes its interaction with an HCR to change from an interse ction to a merger. This produces positive vertical vorticity that causes th e IRE to rotate counterclockwise. The derailed physiography and surface cha racteristics used in this research allow these complex asymmetric interacti ons to be simulated. In addition, the configuration of this simulation allows an even smaller-sc ale feature, KHI, to be observed on top of and behind the Indian River bree ze front. It appears as vortices or billows that grow in amplitude and prop agate backward relative to the front. The structure of the billows agrees w ell with previous theoretical and modeling results. Local regions of upward motion associated with the billows may be a preferred area for postfrontal convection.