The 23rd Conference on Hurricanes and Tropical Meteorology

P7B.22
SURFACE-BASED REMOTE SENSING OF A LANDFALLING TROPICAL STORM

Bruce Albrecht, RSMAS/University of Miami, Miami, FL; and T. Faber, A. Savtchenko, D. Churchill, F. Marks, and P. Black

Data from a 915 MHz Doppler wind profiler were combined with data from the Miami-based WSR-88D radar to define the evolution of the lower tropospheric winds during the passage of Tropical Storm Jerry (1995). The storm made land-fall about 100 km to the north of the site and showed signs of development even as it moved inland. Boundary layer heights inferred from signal-to-noise ratios from the profiler indicate a systematic lowering of the boundary layer from 800 to 400 m during the 12 hours proceeding the passage of the initial strong-band of convection that moves towards the site from the north. At this time the low-level winds shifted from west to northwest as the wind speeds at 200 m increased from 6 to 14 ms-1. A comparison of the winds from the lowest gates of the profiler (~ 120 m) with surface winds indicate vertical shears of about 0.1 s-1 during the 12-hour period following the passage of the initial line of convection. Although the wind profiles from 500 m to the surface during this period occasionally exhibited a log profile, jet-like features were sporadically observed in the 500-1000 m layer. One-minute wind profiles are used to define the temporal evolution of one such jet feature. In addition, statistics on the wind-speed variability from 100-2000 m was obtained using the 1-minute observations. Low-level wind profiles estimated for this case using 88-D VAD scans are being compared with those from the profiler. The utility of using a wind profiler coupled with the WSR 88-D observations to characterize the low-level winds in a tropical storm was clearly demonstrated

The 23rd Conference on Hurricanes and Tropical Meteorology