stat-int

stat-int allows the creation of post-integrated statistics files from .stat files (see Statistics and stat-make). Post-integrated statistics files have the extension .statn where n is the number of scans integrated (by default n is 6, corresponding to a 10 minute integration period).

.statn file structure

In common with .stat files, each integration bin starts with a header block with the following structure:

STRUCTURE /stat_head/ INTEGER*2 stat_rev_no ! statistics revision number INTEGER*2 st_id(2) ! station id (west, east) INTEGER*2 year ! year INTEGER*4 rec_time ! time, secs of year INTEGER*2 tfreq ! frequency RECORD /rev_no/ rev ! fitacf revision number INTEGER*2 no_scans ! number of scans in stats data INTEGER*2 gipercent(2) ! f-o-v %, ground and ion scatter INTEGER*2 stat_res(3) ! reserved for future use INTEGER*2 ndata ! number of data blocks following END STRUCTURE STRUCTURE /rev_no/ !this defines the revision number structure BYTE major BYTE minor END STRUCTURE

no_scans contains the number of scans integrated in the present integration bin (usually equal to n, but less if data gaps exist).

gipercent() is the arithmetic mean f-o-v % ground and ionospheric backscatter for the integrated scans.

The header block is followed by ndata data blocks (one for each summary point in which backscatter was detected within the integration period) of the following format:

STRUCTURE /stat_avdat/ INTEGER*2 point_id ! id of point INTEGER*2 glat ! geographic latitude of point INTEGER*2 glon ! geographic longitude of point INTEGER*2 txstat ! low power Tx status INTEGER*2 gpts ! number of ground scatter points averaged INTEGER*2 ipts ! number of ionospheric scatter points averaged INTEGER*4 gpwr_l ! ground scatter power, dB, lambda fit INTEGER*4 gpwr_s ! ground scatter power, dB, sigma fit INTEGER*4 gvel ! ground scatter velocity, m/s INTEGER*4 gwidth_l ! ground scatter spectral width, m/s, l-fit INTEGER*4 gwidth_s ! ground scatter spectral width, m/s, s-fit INTEGER*2 gelevpts ! number of ground scatter elevation angle points averaged INTEGER*2 gelev ! ground scatter elevation angle INTEGER*4 ipwr_l ! ionospheric scatter power, dB, lambda fit INTEGER*4 ipwr_s ! ionospheric scatter power, dB, sigma fit INTEGER*4 ivel ! ionospheric scatter velocity, m/s INTEGER*4 iwidth_l ! ionospheric scatter spectral width, m/s, l-fit INTEGER*4 iwidth_s ! ionospheric scatter spectral width, m/s, s-fit INTEGER*2 ielevpts ! number of ionospheric scatter elevation angle points averaged INTEGER*2 ielev ! ionospheric scatter elevation angle END STRUCTURE

gpts and ipts indicate the number of scans which contributed to the ground and ionospheric backscatter values.

gelevpts and ielevpts indicate the number of scans which contributed to the ground and ionospheric backscatter elevation angles.

gpwr_l, gvel, etc. and ipwr_l, ivel, etc. indicate the median powers, velocities etc. of ground and ionospheric backscatter respectively.

Caveat

The values of gpwr_l and gvel etc. are median values determined from those scans during which backscatter was detected at the summary point within the integration period. If three or more scans contribute to these values then the power and velocity (etc.) values do not necessarily correspond to the same scan and no relationship can be assumed between them. For this sort of inter-parameter analysis the non-integrated statistics should be employed. Integrated statistics can only be used to give a general indication of the state of the backscatter within the integration period.

.statn file location and creation

Presently, integrated statistics files are not regulary created and should be created ad hoc by the user when necessary.

To create .statn files:

1) Change to the destination directory for the .statn files

2) Execute:

/people/ets/Cutlass/statistics/stat-int file [n]

where file is of the form pathname/95022816f and the (optional) n indicates the number of scans to integrate. n must be a product of 72, otherwise an error is generated. The default value for n is 6.