Version:2.2.9

NumericalData

ResourceHeader

ResourceName

THEMIS Ground-based All Sky Imager; Full Resolution Images.

AlternateName

THEMIS-Ground ASF

ReleaseDate

2018-04-23 15:37:39Z

Description

THEMIS Ground All Sky Imager at Snap Lake: 256 x 256 pixel full resolution images of auroral oval. The ASI stations monitor a 170 degree field of view imaging the auroral oval at kilometer resolution. The ASI is comprised of a fisheye lens and CCD in a stainless steel enclosure topped with a transparent acrylic dome. The CCD has a resolution of 256 x 256 pixels. Exposure control ranges from 5 s to 1 ms although the typical data rate is one image every 3 seconds. Silicone heaters keep the instrument within the nominal temperature range. During daylight hours a sun shades deploy to protect the CCD.

Acknowledgement

We acknowledge NASA contract NAS5-02099 and V. Angelopoulos for use of data from the THEMIS Mission. Specifically: S. Mende and E. Donovan for use of the ASI data, and the CSA for logistical support in fielding and data retrieval from the GBO stations.

Contacts

	Role	Person
1.	PrincipalInvestigator	spase://SMWG/Person/Vassilis.Angelopoulos
2.	CoInvestigator	spase://SMWG/Person/Stephen.B.Mende
3.	CoInvestigator	spase://SMWG/Person/Eric.Donovan

InformationURL

Name

THEMIS Summary Plots

URL

http://themis.ssl.berkeley.edu/gbo/display.py?view_type=summary

Description

Summary plots containing ASI thumbnail images; useful for determining when ASI data exists.

PriorIDs

spase://VMO/NumericalData/THEMIS/Ground/UCLA-GBO/SNAP/ASI/full_PT3S

AccessInformation

RepositoryID

spase://SMWG/Repository/UCB/THEMIS

Availability

Online

AccessRights

Open

AccessURL

Name

THEMIS Web Data

URL

http://themis.ssl.berkeley.edu/data/themis/thg/l1/asi/snap/

Description

Format

CDF

Encoding

None

MeasurementType

ImageIntensity

TemporalDescription

TimeSpan

StartDate

2008-11-01 00:00:00

RelativeStopDate

-P1Y

Cadence

PT3S

Caveats

ASF data is retrieved by physically swapping hard drives at GBO site therefore the data is usually not available for at least 3-5 months.

Parameter #1

Name

thg_asf_snap

ParameterKey

thg_asf_snap

Description

Full images of 256x256 pixels; saturation counts for each pixel.

Units

counts

Structure

Size

256 256

Wave

Qualifier

Scalar

WaveQuantity

Intensity

Parameter #2

Name

thg_asf_snap_column

ParameterKey

thg_asf_snap_column

Description

Image column number; x-dimension, image width.

Structure

Size

256

Support

SupportQuantity

Other

Parameter #3

Name

thg_asf_snap_row

ParameterKey

thg_asf_snap_row

Description

Image row number; y-dimension, image height.

Structure

Size

256

Support

SupportQuantity

Other

Parameter #4

Name

thg_asf_snap_time

ParameterKey

thg_asf_snap_time

Description

Start of integration time, UTC, in seconds since 01-Jan-1970 00:00:00

Caveats

Not including leap seconds

Units

s

ValidMin

0.0

ValidMax

5.0E9

FillValue

NaN

Support

SupportQuantity

Temporal

Parameter #5

Name

thg_asf_snap_tend

ParameterKey

thg_asf_snap_tend

Description

Integration end time, UTC, in seconds since 01-Jan-1970 00:00:00

Caveats

Not including leap seconds

Units

s

ValidMin

0.0

ValidMax

5.0E9

FillValue

NaN

Support

SupportQuantity

Temporal