Monday, 23 January 2012
Investigation of the Vertical Structure of Nocturnal Cold Pools At the Lake Thunderbird Micronet
Hall E (New Orleans Convention Center )
Nocturnal cold pools have long been observed to form in sheltered areas and in shallow depressions. However, in many cases the relative importance of local radiative cooling and thermal advection from drainage and/or katabatic flows in their formation is not clear. As part of an ongoing study to determine the causes of cold pool formation at the Lake Thunderbird Micronet in Norman, Oklahoma, cool pool structure was further investigated. This study included smoke releases that were documented by video recordings. Additionally, two instrument masts were deployed, each consisting of three temperature sensors placed at 1 m, 2 m, and 3 m above ground level, which allowed for comparing the vertical thermal structure of the cold pool and non-cold pool regions. Temperature readings were relayed every minute to a laptop in the home of the landowner for consistent observations. Further, to improve the forecasting of cold pool events, a detailed climatology of cold pools between 1 January and 30 April of 2006, 2007, and 2009-2011 was created. It is shown that while the gradient Richardson number and wind speeds are useful in determining nights in which a cold pool will form, they have no influence on the apparent cold pool strength.