Accession Number : ADA299789

Title :   Estimation of the Convective Boundary Layer Depth over Lake Ontario during Cold Air Outbreaks.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Anstett, Richard A.

PDF Url : ADA299789

Report Date : 10 SEP 1995

Pagination or Media Count : 98

Abstract : The purpose of the research has been to develop and test a simple model for estimating the depth of the convective internal boundary layer (CIBL), and the height of the lifting condensation level (LCL) in the modified air over Lake Ontario. The intent is to use the hourly temporal resolution of surface observations to predict the mixed-layer depth for nowcasting and short-range forecasting purposes. These predicted CIBLs and LCLs are calculated using upwind surface and sounding data, and lake surface temperatures, and compared with downwind soundings made with mobile radiosondes. Factors such as the effects of upwind lakes, upward CIBL growth into layers of differing stability, and air mass modification over Lake Ontario are investigated. This study was conducted using data from the Lake Ontario Winter Storms (LOWS) Project; an investigation of the mesoscale structure and physical processes involved in lake-effect snowstorms east of Lake Ontario between 5 January and 1 March 1990. The LOWS Project final technical report suggests that the convective layer depth is at least as important to forecasting lake-effect intensity as the instability. It has been shown that organized convection is inhibited by low capping inversions, even with lake surface to 850 mb temperature differences much greater than the dry adiabatic lapse rate (approx. 13 deg C). Soundings for the LOWS Project were conducted at Egbert, Canada for upwind data, and downwind of Lake Ontario at Buffalo, NY and also with mobile radiosondes. Regular synoptic soundings are conducted at upwind locations west of Lake Huron, while Buffalo, NY is downwind of Lakes Erie and Ontario.

Descriptors :   *BOUNDARY LAYER, *CONVECTION(ATMOSPHERIC), *LAKE ONTARIO, MATHEMATICAL MODELS, COMPUTERIZED SIMULATION, REAL TIME, ATMOSPHERIC TEMPERATURE, THESES, WEATHER FORECASTING, MOISTURE CONTENT, PROFILES, SNOW, WINTER, CASE STUDIES, STORMS, WIND DIRECTION, WIND VELOCITY, RADIOSONDES, AIR WATER INTERACTIONS, SURFACE TEMPERATURE, CLOUD PHYSICS, ADIABATIC CONDITIONS, ATMOSPHERE MODELS, CONDENSATION, AIR MASSES, ATMOSPHERIC SOUNDING, DEW POINT, COLD FRONTS, LAKE HURON.

Subject Categories : Meteorology
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE