Statistics

The statistics summary points

Sixteen 'summary points' have been selected as being a representative sample of the whole Cutlass field of view (16 beams x 75 range gates = 1200 points). For the Findland radar the summary points, numbered 0 to 15, all fall in beam 9:

Point Range Geographic
Number Beam gate Lat Lon
0 9 13 68 24
1 9 15 68 24
2 9 18 70 23
3 9 20 70 23
4 9 23 72 22
5 9 25 72 21
6 9 27 73 21
7 9 30 74 20
8 9 32 75 19
9 9 35 76 17
10 9 37 77 16
11 9 40 78 14
12 9 43 79 12
13 9 46 81 9
14 9 49 82 6
15 9 52 83 1

File structure

Statistics information is stored in 2 hour long files (in the same way as .fit files) with the file extension .stat, e.g. 95022816f.stat. Statistics files are usually stored in the directory structure /cutlass/statistics. Subdirectories of the form finland/95 or iceland/96 hold the files for each radar and year.

Each 2 hour file contains up to 72 scans (on rare occasions 73 scans) of 100s duration each. Each scan has a header block containing time information, the percentage of the Cutlass field of view in which ground and ionospheric backscatter is detected, and the number of summary points in which backscatter was detected. A separate data block for each of these summary points contains noise, power, and spectral width parameters and an ionospheric or ground backscatter flag. (For more information see stat-make.)

.stat files are regularly created at the same time as the archiving of .fit files.

Post-integrated statistics

Post-integrated statistics files can also be created, in which the mean or median of certain parameters for each summary point from several scans is recorded. The usual integration period is 6 scans (10 minutes). These files have the extension .statn where n is the number of scans integrated.

Statistics routines

Fortran routines stat-make and stat-int exist to create statistics files from .fit files, and post-integrated statistics files from .stat files respectively.

An IDL statistics package also exists to allow statistics files to be read and manipulated.

Bugs and revisions

Check the bugs and revisions notes on the stat-make page.