The data set comprises ionospheric vorticity estimates determined from measurements of ionospheric velocity made by overlapping pairs of northern hemisphere radars in the Super Dual Auroral Radar Network (SuperDARN). The vorticity estimates are separated into data files for each pair of SuperDARN radars that contributed to the whole data set. These data cover large regions of the northern hemisphere polar ionosphere, and the locations of the vorticity estimates are presented in both geographic and Altitude-Adjusted Corrected GeoMagnetic (AACGM) co-ordinates. The data cover the interval from 2000 to 2005 inclusive.
This work was funded by NERC grant reference NE/R016038/1.
SuperDARN, ionosphere, vorticity
Chisham, G. (2023). Ionospheric vorticity across the northern hemisphere ionosphere determined from particular SuperDARN radar pairs - 2000 to 2005 inclusive (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/8eedc594-730b-4aad-b9ce-827912320c3a
|Access Constraints:||No restrictions apply.|
|Use Constraints:||Data supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/.|
|ISO Topic Categories:||
|Name||UK Polar Data Centre|
|Organisation||British Antarctic Survey|
|Role(s)||Investigator, Technical Contact|
|Organisation||British Antarctic Survey|
|Reference:||Chisham and Freeman (2023), The balance between turbulent and convection-driven plasma vorticity in the Earth's ionosphere, in preparation for submission to J. Geophys. Res.
Chisham and Freeman (2021), A statistical model of vorticity in the polar ionosphere and implications for extreme values, J. Geophys. Res., 126, e2021JA029307, doi:10.1029/2021JA029307.
Chisham and Freeman (2010), On the non-Gaussian nature of ionospheric vorticity, Geophys. Res. Lett., 37, L12103, doi:10.1029/2010GL043714.
Chisham et al. (2009), Spatial distribution of average vorticity in the high-latitude ionosphere and its variation with interplanetary magnetic field direction and season, J. Geophys. Res., 114, A09301, doi:10.1029/2009JA014263.
Chisham et al. (2008), Mapping ionospheric backscatter measured by the SuperDARN HF radars - Part 1: A new empirical virtual height model, Ann. Geophys., 26, 823-841, doi:10.5194/angeo-26-823-2008.
|Quality:||The overall quality of the vorticity estimates is highly dependent on the raw SuperDARN velocity data that provide the primary data source. These are generally of high quality with low errors. The quality of the vorticity estimates is mostly affected by missing velocity data around the closed loops. To mitigate this, the vorticity estimates are only determined when adequate SuperDARN velocity data covering all sides of the closed loop are available. See Chisham et al. (2009) for full details regarding data quality.|
|Lineage:||The vorticity estimates are determined by taking SuperDARN line-of-sight velocity measurements of the ionospheric plasma flow around spatially closed loops determined by the geometry of the SuperDARN beam look directions. The vorticity at the centre of these closed loops is determined by summing the flow velocity around the loops, and dividing by the area, using Stokes' theorem. The ionospheric vorticity determination methodology is outlined in detail in Chisham et al. (2009).|
|Min Altitude||200 km|
|Max Altitude||400 km|
|Detailed Location||Canada, USA, Iceland and Northern Europe|
|Data Collection:||The data set comprises vorticity estimates from the following overlapping pairs of SuperDARN radars: (1) Kodiak (a) and Prince George (b); (2) Saskatoon (t) and Kapuskasing (k); (3) Stokkseyri (w) and Goose Bay (g); (4) Finland (f) and Pykkvibaer (e). The raw data were analysed using the SuperDARN FitACF v2.5. The data were geolocation mapped using the Chisham et al. (2008) virtual height model. The vorticity locations are presented in both geographic and Altitude-Adjusted Corrected GeoMagnetic (AACGM) co-ordinates.|
|Distribution Media||Online Internet (HTTP)|
|Distribution Size||4.0 GB|
|Data Storage:||There are 8 files, all in a space-delimited ASCII format. The data files are:
The first two letters in the filename represent the two overlapping SuperDARN radars used for that data file: a - Kodiak; b - Prince George; e - Pykkvibaer; f - Finland; g - Goose Bay; k - Kapuskasing; t - Saskatoon; w - Stokkseyri. The closed loops used in the vorticity determination use adjacent beams, unless the filename contains x# (where # is a number) after the radar identifiers. In these files, the vorticity determination uses beams that are separated by # beams. The v in the filename represents vorticity, and the trailing numbers represent the start (00) and end (05) years of the data sets.
Each data file has the following format:
(Followed by a series of data records of the form...)
Year, Month, Day, Decimal Hour
(Followed by Number x 3 line records, where the first line is of the form...)
r1_b1, r1_b2, r2_b1, r2_b2, Area, Vorticity, MLT
r1_b1 - The first beam from radar 1 used to form the closed loop for analysis.
r1_b2 - The second beam from radar 1 used to form the closed loop for analysis.
r2_b1 - The first beam from radar 2 used to form the closed loop for analysis.
r2_b2 - The second beam from radar 2 used to form the closed loop for analysis.
Area - The area within the closed loop, in km2.
Vorticity - The measured vorticity in Hz - The sign here is opposite to the new convention (as is outlined in the papers). When analysing it is recommended to multiply vorticity values by a value of -1000 to retrieve the vorticity in mHz, and with the modern sign convention.
MLT - Magnetic Local Time, in hours.)
(And the second and third lines are of the form...)
coord_index, lat_c, long_c, lat_1, long_1, lat_2, long_2, lat_3, long_3, lat_4, long_4
coord_index - This index is 0 for geographic co-ordinates and 1 for AACGM co-ordinates.
lat_c, long_c - The co-ordinates of the centre of the diamond that defines the closed loop, with latitude in units of degree_north and longitude in units of degree_east.
lat_1, long_1, ..., lat_4, long_4 - The co-ordinates of the four vertices of the diamond that defines the closed loop, with latitude in units of degree_north and longitude in units of degree_east.)