Identification

Title

Dynamics and electrodynamics of an ultra-fast kelvin wave (UFKW) packet in the ionosphere-thermosphere (IT)

Abstract

Numerical experiments are performed using a suite of general circulation models that enable the interaction between a Kelvin wave packet and the ionosphere-thermosphere (IT) to be elucidated. Focus is on an eastward-propagating ultra-fast Kelvin wave (UFKW) packet with periods between 2 and 4 days and zonal wavenumber s =−1 during day of year (DOY) 266–281, 2009. Dissipative processes modify the classic UFKW dynamics (equatorially trapped, small meridional wind component) in three ways: (1) molecular diffusion acts to spread the UFKW zonal (u ) and meridional (v ) wind fields meridionally, pole to pole, as u and v , respectively, decay and grow with increasing height; (2) due to molecular diffusion, the UFKW spectrum at longer periods and with shorter vertical wavelengths preferentially dissipates with height; and (3) interaction with the diurnally varying IT introduces a westward-propagating s =+2 component to the wind field that significantly modifies its longitude-UT structure to include a diurnal modulation. The F-region ionosphere also responds with s =+2, which originates from the influence of diurnally varying E-region conductivity on E ×B drifts. Additional spectral peaks in v and ionospheric parameters arise due to longitude variations in the magnetic field. Maximum excursions in NmF2 (as compared with those from a simulation without UFKW forcing) achieve values as large as ±50% but more commonly occur in the range of ±20-30%. The combination of positive and negative responses, and their relative magnitudes, depends on the phasing of the UFKW as it moves zonally relative to the Sun-synchronous diurnal variation of the ionosphere, in addition to its changing amplitude between DOY 266 and 282. Modifications of order 10 ms−1 and −7% to zonal-mean zonal winds and NmF2, respectively, also result from dissipation of the UFKW packet.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7js9sv5

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

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keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

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East bounding longitude

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South bounding latitude

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date type

publication

effective date

2020-05-01T00:00:00Z

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None

Responsible organisations

Responsible party

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

responsible party role

pointOfContact

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