Sunday, 22 January 2012
A Precipitation Climatology for the Green River Watershed in Kentucky During 1979-2010
Hall E (New Orleans Convention Center )
The Green River Watershed, home to the Mammoth Cave system in west-central Kentucky, is a region heavily utilized for agriculture, which raises concerns about the transport of pollutants and the impact on water quality. The purpose of this study is to help predict the transport of pollutants through the watershed by first, conducting a warm season (spring-summer) precipitation climatology over the basin for the period of record 1979-2010. Average rainfall amounts were derived from daily precipitation observations from National Weather Service Cooperative weather stations. Synoptic circulation types were subjectively derived from archived analyzed surface and upper-air maps from the NOAA Daily Weather Maps series. The five different synoptic circulation patterns included synoptic, wraparound, frontal, tropical, and other Preliminary results show that mean basin warm season rainfall for the POR is 642 mm. In terms of interannual variability, the years 1979, 2003, 2007 and 2010 showed the greatest deviation (≥ ±2 σ) from normal. It is possible that the interannual variability is linked to variations in the ENSO cycle. Synoptic precipitation days were the most frequent and contributed the majority (56%) of the annual average precipitation, with frontal contributing 21.1%, and Other-MT (air-mass storms) contributing 11.2%. Average precipitation associated with synoptic events were statistically greater (95% confidence interval) than all other events, except when compared to tropical events. Analysis of the intraseasonal variability in mean basin precipitation showed that on average, the most precipitation occurred late April through mid May (150 mm), with the most precipitation between the days May 5th-6th.