Identification

Title

Dependence of the high-latitude lower thermospheric wind vertical vorticity and horizontal divergence on the interplanetary magnetic field

Abstract

We analyze the vertical component of vorticity and the horizontal divergence of the high-latitude neutral wind field in the lower thermosphere during the southern summer time for different interplanetary magnetic field (IMF) conditions with the aid of the National Center for Atmospheric Research thermosphere ionosphere electrodynamics general circulation model, with the following results. (1) The mean neutral wind pattern in the high-latitude lower thermosphere is dominated by rotational flow, imparted primarily through the ion drag force rather than by horizontally divergent flow. (2) The vertical vorticity depends on the IMF. (3) The difference vertical vorticity, obtained by subtracting values with zero IMF from those with nonzero IMF, is much larger than the difference horizontal divergence for all IMF conditions. (4) The effects of IMF penetrate down to 106 km altitude. To determine the processes forcing strong rotational flow in the high-latitude lower thermospheric wind fields, a term analysis of the vorticity equation is also performed, with the following results. (1) The primary forcing term that determines variations of the vertical vorticity is ion drag. This forcing is closely related to the flow of field-aligned current between the ionosphere and magnetosphere. Significant contributions to variations of the vorticity, however, can be made by the horizontal advection term. (2) The effects of the IMF on the ion drag forcing are seen down to around 106 km altitude. (3) The continual forcing of magnetic zonal mean By-dependent vertical vorticity by ion drag can lead to strong polar vortices.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7rr205j

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2014-02-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

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name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

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

Metadata on metadata

Metadata point of contact