Radar signatures of the urban effect on precipitation distribution: A case study for Atlanta, Georgia

Ground-based weather radar from Peachtree City, GA, is used to examine the distribution of summer precipitation in northern Georgia, including metropolitan Atlanta, during June-August of 2002-2006. The study included 194 "synoptically benign" days with a maritime tropical air mass type. Areas in eastern metropolitan Atlanta are shown to have 30% more rainfall during these days than areas west of the city. Both precipitation amount and frequency were enhanced up to 80 km to the east of the urban core of Atlanta. A precipitation maxima northeast of Atlanta occurs near a precipitation anomaly and lightning flash density anomaly identified in previous studies. An hourly analysis of precipitation data demonstrates that the enhanced precipitation on the periphery of the urban core is most evident from 00-05 UTC ( 19-00 LST). This study is the first to use ground-based radar precipitation estimates in an attempt to quantify the impact of urbanization on precipitation.