Identification

Title

Solar cycle variations of thermospheric O/N longitudinal pattern from TIMED/GUVI

Abstract

Thermospheric composition (O/N2 ratio) is well known to have a great impact on the variation of daytime ionospheric electron density. This study aims to investigate the local time, seasonal, and solar cycle variations of the O/N2 longitudinal pattern in both hemispheres during daytime in solstices. The O/N-2 data used are from TIMED/Global Ultraviolet Imager observations made over a solar cycle for geomagnetically quiet conditions. The main findings are as follows:(1) The O/N-2 longitudinal patterns are generally similar during 10:00-14:00 LT and between solar minimum and maximum, although the O/N-2 values change with local time and solar cycle. (2) The winter O/N-2 subauroral enhancement is unexpectedly smaller in the longitudeswhere the magnetic pole is (near-pole longitudes), rather than in the longitudes far from the magnetic pole, especially during solar maximum, and consequently, the longitudinal pattern of O/N-2 depends on latitude in local winter. (3) The winter O/N-2 subauroral enhancement generally moves to more poleward latitudes during solar maximum, as compared to solar minimum. (4) At higher midlatitudes (similar to 45 degrees -60 degrees N and similar to 40 degrees-50 degrees S in geographic latitudes) in solar minimum, the winter-to-summer ratio of O/N-2 in each hemisphere has an obvious minimum in near-pole longitudes. This minimum becomes more evident during solar maximum. The National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model simulations indicate that in the winter hemisphere, the unexpected O/N-2 longitudinal pattern in higher midlatitudes is mainly associated with high-latitude Joule heating under the impact from ion convection and auroral precipitation.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d72j6dn1

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

2017-02-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

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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