Accession Number : ADA258575
Title : The Role of Conditional Symmetric Instability in the Development of Moderate to Heavy Frozen Precipitation Bands.
Descriptive Note : Master's thesis,
Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
Personal Author(s) : Lambert, Thomas E
Report Date : Jan 1992
Pagination or Media Count : 127
Abstract : The relationship between conditional symmetric instability (CSI), slantwise convection, and heavy frozen precipitation in winter type extratropical cyclones (ETCs) is analyzed for several cases where thunder and frozen precipitation were reported. Analysis of the atmosphere's vertical temperature, humidity, and wind field structure was used to identify areas of CSI and the atmospheric conditions that may serve as precursors to the development of CSI. Vertical cross sections showing areas of CSI were used to provide insight into when and where slantwise convection could be expected. A correlation was found between vertical motion, vertical wind shear, the equivalent potential temperature (theta-e) field, and areas of CSI, slantwise convection, and heavy frozen precipitation. Regions of moderate to strong upward vertical motion, strong vertical wind shear, and small increases or even decreases in theta-e with height are the regions where CSI tends to develop in winter type ETCs. Areas of CSI were present in all cases where thunder and frozen precipitation were reported. CSI creates conditions favorable for the development of slantwise convection and the heavy frozen precipitation it sometimes produces.
Descriptors : *ATMOSPHERIC PRECIPITATION , THESES , TROPICAL CYCLONES , SYMMETRY
Subject Categories : Meteorology
Distribution Statement : APPROVED FOR PUBLIC RELEASE