Urbanization and the Regional Rainfall Climatology of the Baltimore Metropolitan Region

A 10-year, high-resolution rainfall data set for the Baltimore metropolitan region is used to examine urbanization effects on the regional rainfall climatology and associated elements of the urban water cycle. Rainfall fields are developed at 1 km spatial resolution and 15-minute time resolution based on radar reflectivity observations from the Sterling, VA WSR-88D radar and rain gage observations from diverse networks in the region. The warm season (June - August) rainfall climatology for the Baltimore region exhibits sharp spatial gradients in a diverse array of statistical properties characterizing mean rainfall, rainfall extremes and rainfall occurrence. In addition to urbanization effects, these properties are linked to the effects of mountainous terrain to the west and land-water boundaries to the east. The rainfall data set covers the principal study watersheds of the Baltimore Ecosystem Study (BES; a component of the NSF LTER program). Analyses of urbanization impacts on the storm event water balance are carried out for gaged watersheds in the BES region.