1GraduatePrograminEarthandSpaceScience,York.ppt

* * * * * 1Graduate Program in Earth and Space Science, York University, Toronto, Ontario 2Environment Canada, Cloud Physics and Severe Weather Research Section, Toronto, Ontario Yi (Emily) Zhou1, George Isaac2, 1, Peter Taylor1 Introduction Low level wind shear criteria Method of interpolation AMDAR low level wind shear analysis Frequency of low level wind shear Case study Summary Low Level Wind Shear at Pearson Airport 1. Introduction Low level wind shear : change of horizontal wind direction and/or speed with height ((?U/?z, where U is horizontal wind) Dangerous: increase/decrease of head wind (tail wind), hence an increase /decrease of lifting force, causing the aircraft to fly above or below its intended flight path. A survey conducted by the International Civil Aviation Organization showed that from 1964 to 1983, low level windshear caused at least 28 large transport aircraft accidents in the world that together resulted in over 500 fatalities and 200 injuries. Tasks Study low level wind shear from models’ out put (GEM-15 Regional, GEM-2.5 LAM and RUC-13) Analysis of low level wind shear from AMDAR (Aircraft Meteorological Data Reports) wind profile data for Pearson Airport Case study Data: From CAN-Now Archive Files: Pearson M300 Data (2007-07-13 to 2009-03-31) GEM-15 Regional (2007-02-27 to 2009-03-12) GEM-2.5 LAM (2007-03-13 to 2009-03-12) RUC-13 model data (2007-08-20 to 2009-03-11) AMDAR data in netCDF from (2007-07-13 to 2009-03-31) 2. Low level wind shear criteria According to MANAIR 2.6.7(MANAIR - manual of standards and procedures for aviation weather forecasts), the vertical non convective low level wind shear criteria are listed as: Wind vector change greater than 25 knots within 500 ft AGL. Wind vector change greater than 40 knots within 1000 ft AGL. Wind vector change greater than 50 knots within 1500 ft AGL. A PIREP indicates a loss or gain of indicated airspeed of 20 knots or more, within 1500 ft AGL. When any of the