Identification

Title

The evolution of mountain waves and rotors in the lee of Pike's Peak under the influence of a cold front: Implications for aircraft safety

Abstract

A lee-wave--rotor system interacting with an approaching cold front in the lee of Pike's Peak near Colorado Springs, Colorado, on 1 April 1997 is studied observationally and numerically. Dynamical effects associated with the approaching cold front caused the amplification of the evolving lee wave and rotor, creating increasingly more hazardous flight conditions for nearby airports. The rapidly evolving winds measured by a Doppler lidar and 915-MHz wind profilers, and simulated by the Regional Atmospheric Modeling System (RAMS), produced light-to-moderate turbulence for a research aircraft making missed approaches at the Colorado Springs Airport during the wave amplification phase. As the cold front approached the foothills, the lee-wave--rotor system ended abruptly, reducing hazardous flight conditions. The Doppler lidar's detailed measurements of the lee-wave--rotor system allowed for an evaluation of RAMS ability to capture these complex wind features. Qualitative and quantitative comparisons between the lidar range--height measurements and model x-z cross sections are presented. In a broad sense, the numerical simulations were successful in the prediction of the prefrontal amplification and the postfrontal decay of the waves as measured by the lidar. RAMS also predicted observed wind reversals above the lee waves, which were indicators of breaking wave instability. At times RAMS performed poorly by over- or underpredicting the wind speeds in the lee wave, as well as the horizontal extent of the lee wave or rotor.

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document

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https://n2t.org/ark:/85065/d7125t0z

codeSpace

Dataset language

eng

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geoscientificInformation

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title

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publication

effective date

2016-01-01T00:00:00Z

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publication

effective date

2006-10-01T00:00:00Z

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Copyright 2006 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work.

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OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

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pointOfContact

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