GRID files
GRID files are post-processed data produced from FITACF files, in which the fitted data products are placed on a magnetic latitude/longitude grid of equal-area cells spanning 1 degree of magnetic latitude. They may contain data from one radar or from multiple radars. For more information, see the make_grid
tutorial.
Naming Convention
The community standard for naming GRID files containing data from only one radar is:
YYYYMMDD.<3-letter abbreviation>.grd
When the gridded data from multiple radars have been combined, the files are named as:
YYYYMMDD.north.grd
YYYYMMDD.south.grd
In both cases, the grid files contain 24-hours of data.
Note
Combined grid files should contain data from a single hemisphere only.
Scalar Fields
The following times refer to the start and end of the integration period.
Field name | Units | Data Type | Description |
---|---|---|---|
start.year | None | short | Start Year |
start.month | None | short | Start Month number (not padded) |
start.day | None | short | Start Day (not padded) |
start.hour | hrs | short | Start Hour |
start.minute | min | short | Start Minute |
start.second | s | short | Start Seconds |
end.year | None | short | End Year |
end.month | None | short | End Month (not padded) |
end.day | None | short | End Day (not padded) |
end.hour | hrs | short | End Hour |
end.minute | min | short | End Minute |
end.second | s | short | End Seconds |
Vector Fields
In the table below, numstid is the number of radars included in that grid record, and numv is the total number of gridded velocity vectors.
Field name | Units | Dimensionality | Data Type | Description |
---|---|---|---|---|
stid | None | [numstid] | short | A list of numeric station IDs that provided data for the record |
channel | None | [numstid] | short | A list of channel numbers associated with the station id |
nvec | None | [numstid] | short | Number of velocity vectors for each station |
freq | kHz | [numstid] | float | Transmitted frequency for each radar |
major.revision | None | [numstid] | short | Major make_grid version number |
minor.revision | None | [numstid] | short | Minor make_grid version number |
program.id | None | [numstid] | short | Control program ID |
noise.mean | None | [numstid] | float | Mean noise |
noise.sd | None | [numstid] | float | Noise Standard deviation |
gsct | None | [numstid] | short | Groundscatter flag |
v.min | m/s | [numstid] | float | Minimum velocity threshold |
v.max | m/s | [numstid] | float | Velocity maximum threshold |
p.min | None | [numstid] | float | Power minimum threshold |
p.max | None | [numstid] | float | Power maximum threshold |
w.min | m/s | [numstid] | float | Spectral width minimum threshold |
w.max | m/s | [numstid] | float | Spectral width maximum threshold |
ve.min | m/s | [numstid] | float | Velocity error minimum threshold |
ve.max | m/s | [numstid] | float | Velocity error maximum threshold |
vector.mlat | degrees | [numv] | float | Magnetic Latitude |
vector.mlon | degrees | [numv] | float | Magnetic Longitude |
vector.kvect | degrees | [numv] | float | Magnetic Azimuth |
vector.stid | None | [numv] | short | Station identifier |
vector.channel | None | [numv] | short | Channel number |
vector.index | None | [numv] | int | Grid cell index |
vector.vel.median | m/s | [numv] | float | Weighted mean velocity magnitude |
vector.vel.sd | m/s | [numv] | float | Velocity standard deviation |
vector.pwr.median | dB | [numv] | float | Weighted mean power |
vector.pwr.sd | dB | [numv] | float | Power standard deviation |
vector.wdt.median | m/s | [numv] | float | Weighted mean spectral width |
*vector.wdt.sd | m/s | [numv] | float | Standard deviation of spectral width |