NDVI ANALYSIS OF HAIL SWATHS ASSOCIATED WITH THE 5 MAY 1995 PARKER COUNTY AND TARRANT COUNTY, TEXAS, HAILSTORM

摘要

A devastating hailstorm moved through the north Texas counties of Parker and Tarrant on the 5th of May 1995, causing extensive damage to structures and vegetation. Remote sensing techniques by means of normalized difference vegetation indices (NDVI),image differencing, and change detection were utilized to assess severe hail damage areas associated with the storm. Weather Surveillance Radar - 1988 Doppler (WSR-88D) Level II data from the time of the storm were spatially compared to the NDVI classified hail damage swaths. Analysis shows a statistical correlation exists between WSR-88D radar returns and hail damage for the rural areas of Parker County, with no correlation evidenced for the urban areas of Tarrant County; although hail damage areas canbe visually identified for parts of the city of Fort Worth. Statistical results indicate that remote sensing NDVI methods are valid for identification of hail swaths in relatively rural areas, but have a lesser application for detection in densely populated urban regions. Comparison of the NDVI change detection to in-situ observations of the hail event show that greater negative NDVI change values are indicated in areas that experienced the greatest hail density compared to areas which experienced thelargest hail size.