Document Type

Article

Journal/Book Title/Conference

Atmospheric Measurement Techniques

Volume

12

Issue

11

Publisher

Copernicus GmbH

Publication Date

11-19-2019

First Page

5997

Last Page

6015

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Abstract

We analyse gravity waves in the upper-mesosphere, lower-thermosphere region from high-resolution temperature variations measured by the Rayleigh lidar and OH temperature mapper. From this combination of instruments, aided by meteor radar wind data, the full set of ground-relative and intrinsic gravity wave parameters are derived by means of the novel WAPITI (Wavelet Analysis and Phase line IdenTIfication) method. This WAPITI tool decomposes the gravity wave field into its spectral component while preserving the temporal resolution, allowing us to identify and study the evolution of gravity wave packets in the varying backgrounds. We describe WAPITI and demonstrate its capabilities for the large-amplitude gravity wave event on 16–17 December 2015 observed at Sodankylä, Finland, during the GW-LCYCLE-II (Gravity Wave Life Cycle Experiment) field campaign. We present horizontal and vertical wavelengths, phase velocities, propagation directions and intrinsic periods including uncertainties. The results are discussed for three main spectral regions, representing small-, medium- and large-period gravity waves. We observe a complex superposition of gravity waves at different scales, partly generated by gravity wave breaking, evolving in accordance with a vertically and presumably also horizontally sheared wind.

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