Identification

Title

Signatures of thermospheric‐exospheric coupling of hydrogen in observed seasonal trends of H α intensity

Abstract

Analysis of an established geocoronal H α data set indicates a seasonal trend in observed dusk‐to‐dawn intensity variation, consistent with a diurnal variation in the underlying thermospheric hydrogen density. Observations were obtained at Pine Bluff Observatory, WI, from 2000 to 2001 using a high spectral resolution (R∼80,000) Fabry‐Perot annular summing spectrometer. This dusk‐to‐dawn asymmetry in intensity is highest in winter months with a difference of ∼2.7 Rayleighs and smallest in summer months with a difference of ∼0.5 Rayleighs; observations near equinox show a dusk‐to‐dawn difference in intensity close to ∼1.3 Rayleighs. Comparisons between modeled and observed dusk‐to‐dawn intensity variation show good agreement near the equinoxes. The modeled intensity was generated using the lyao_rt radiative transport code of Bishop (1999, https://doi-org.cuucar.idm.oclc.org/10.1016/S0022-4073(98)00031-4), employing NRLMSISE‐00 thermospheric hydrogen profiles extended into the exosphere via the evaporative case of the Bishop analytic exosphere. Near the equinoxes and summer solstice, the model tends to agree with observations. Near the winter solstice, the model underestimates the dusk‐to‐dawn asymmetry by 1.5–2 Rayleighs. Overall, modeled H α intensity generated with NRLMSISE‐00 as the thermospheric input is shown to be consistently lower than observed intensity by a factor of ∼2.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7wd422k

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

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South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2019-06-01T00:00:00Z

Frequency of update

Quality and validity

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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