Recorded presentation9.6
Satellite signatures associated with significant convectively-induced turbulence events
Kristopher M. Bedka, CIMSS/Univ. of Wisconsin, Madison, WI; and W. F. Feltz, J. R. Mecikalski, R. D. Sharman, A. Lenz, and J. Sieglaff
A 2.5 year database of objective Eddy Dissipation Rate (EDR) turbulence observations has recently been processed to produce a climatology of significant turbulence events over the eastern half of the United States. These observations, collected by United Airlines Boeing 737 and 757 commercial airliners, provide a quantification of the vertical acceleration of an aircraft induced by turbulent weather phenomena. EDR observations provide an advantage over traditional subjective pilot reports (PIREPS), allowing one to precisely pinpoint the time, location, and intensity of a given turbulence episode.
As part of a NASA-funded effort, an emphasis has been placed on improving the diagnosis and forecasting of convectively-induced turbulence (CIT) events. From this EDR climatology, events were identified with a number of moderate to severe observations exceeding three standard deviations from the daily convective season (April-October) mean. These events, representing the top 1% of all convective season days in the turbulence climatology, were studied using all available high temporal (GOES), spatial (MODIS, AVHRR), and spectral (MODIS) resolution satellite instrument observations. CIT events often occurred in association with cold convective cloud tops (< -40° C) and the existence of convective gravity waves, banded cirrus outflow structures (i.e. “transverse bands”), rapid anvil expansion indicating strong cloud-top divergence/outflow, or rapidly developing, near-mature convection.
The ultimate objective of this work is to identify a set of satellite-observed characteristics that can be objectively identified to improve the forecasting of significant convectively-induced turbulence events within the FAA-sponsored Graphical Turbulence Guidance (GTG) system. This presentation will focus on the results of this analysis to-date and preliminary conclusions.
Session 9, Turbulence and Wind Shear Part I
Wednesday, 23 January 2008, 4:00 PM-5:30 PM, 226-227
Previous paper