Identification

Title

Divergence and vorticity from aircraft air motion measurements

Abstract

This paper considers the accuracy of divergence estimates obtained from aircraft measurements of the horizontal velocity field and points out an error that appears in these estimates that has heretofore not been addressed. A procedure for eliminating this error is presented. The divergence and vorticity are estimated from the coefficients of a least squares fit to a wind field obtained from the Second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) circular flight legs. These estimates are compared with estimates from numerical models and satellites and with airplane estimates based on tracer budgets and the temporal changes in cloud-top height. The estimates are consistent with expectations and estimates using other methods, albeit somewhat high. Furthermore, significant differences occur among the cases, likely due to the large differences in the techniques. The results indicate that the wind field technique is a viable approach for estimating mesoscale divergence if the wind measurements are accurate. The largest source of wind field systematic error may be the result of flow distortion effects on the air velocity measurement and limitations of in-flight calibrations. Because of flow distortion, the only way the current systems can be calibrated is by flight maneuvers, which assume a steady-state homogeneous nonturbulent atmosphere. Analysis of the errors in this technique suggests that wind field measurements with minimal systematic errors should provide estimates of divergence with much greater accuracy than is now possible with other existing methods.

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document

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https://n2t.org/ark:/85065/d7s46s5p

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Dataset language

eng

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geoscientificInformation

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publication

effective date

2016-01-01T00:00:00Z

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publication

effective date

2007-12-01T00:00:00Z

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Copyright 2007 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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contact position

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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