WMOD00526

• Title: Quality Control and Archiving of Digital Data Gathered by the Bureau of Reclaimation's Weather Radar
• Date: 12/12/1989
• Weather Modification - Doc Type: Report

DECEMBER 1989

NOTES AND CORRESPONDENCE

b. Description of magnetic tape record

Each magnetic-tape record (Fig. 1) consists of 22
frames of header ("housekeeping") information (date,
time, record count, and parameter and status settings)
and four sets of the following: (i) Four frames of azi-
muth and elevation data; (ii) 250 frames of averaged-
echo range-bin data; (iii) three frames ofproject aircraft
positions; and (iv) three frames of averaged-echo range
bin data. Thus each record is a fixed length of 1062
frames where each frame is an 8-binary-bit byte. The
data are recorded onto reels of tape of density 1600
characters per inch ( cpi) and a length of approximately
730 m. Each record is nearly 1.7 cm long with inter-
record gaps of approximately 1.6 cm separating each
record. A full tape can hold approximately 22 000 rec-
ords, representing from 1 to 6 hours of data acquisition
time, depending on percent of surrounding echo cov-
erage and data acquisition-rate settings.
Housekeeping information includes a range delay
setting (frame 7 in Fig. 1) which is selectable from 00
to 99 km (two Binary Coded Decimal digits) and is
used to specify the range of the first data bin. The blue
sky setting (frame 9), which is also selectable from 00
to 99 DVIP units, is set by the radar operator following
a perusal of the background noise information for data
collected when the antenna is pointed to yield mini-
mum-return echo signals. For instance, the operator
may see that the background noise values are generally
34 to 40 DVIP units and might set a 43 DVIP unit
value for the blue sky setting. A change of 3 DVIP
units is equivalent to a change in power returned of 1
dBm. The ID Code (frame 12) is selectable from 00
to 99 and is a number used to identify a particular
project site. The first bit in frame 8 and all eight bits
in frame 11 define important status conditions. The
various bits configurations are defined in the six "Status
Format" tables in Fig. 1.
The digitized power-returned data are usually re-
corded in the logarithmic receiver mode. A typical bit
configuration for status frame 11 is 11000010 (hex-
adecimal C2). This indicates PPI mode, which is a
normal 3600 azimuthal sweep ( I ), an azimuth incre-
ment of 10 (1), a PRF of 414 Hz (0),8 pulse samples
per averaged return (00), and a range-bin interval of
0.5 km (010).
The spatial bounds of each range bin are defined by
the range delay, the range interval, and the azimuth
increment. For instance, if these three parameters are
set to 30 km, 0.5 km, and 10, respectively, then the
first range bin (frames 27, 287, 547, 807) is 30.0 to
30.5 km by lOin width. The second range bin (frames
28, 288, 548, 808) is 30.5 to 31.0 km by lOin width,
etc. The DVIP values assigned to each range bin con-
tain the binary equivalent ofa number up to 255, which
is directly related to the average power received for the
corresponding range and azimuth intervals.

LOG I CAL TRACK NUMBER
1234567

0 0 200 100 80 40 20 10
8 4 2 1 Z E R 0
0 0 20 10 8 4 2 I
0 40 20 10 8 4 2 1
RES 40 20 10 8 4 2 1
80 40 20 10 8 4 2 1
80 40 20 10 8 4 2 1
III Z E R 0
80 40 20 10 8 4 2 1
Z E R 0
RHI AI PRF SAl SRO RI2 RII RIO
80 40 20 10 8 4 2 1
Z E R 0 80K 40K 20K 10K
8K 4K 2K lK 800 400 200 100
80 40 20 10 8 4 2 1
Z E R 0
Z E R 0
Z E R 0
Z E R 0
0 0 200 100 80 40 20 10
8 4 2 1 .8 .4 .2 1
0 0 0 100 80 40 20 10
8 4 2 1 8 .4 2 1
128 64 32 16 8 4 2 1
BYTES 27 - 275 RADAR ECHO
'28 64 32 16 8 4 2 1
128 64 32 .6 8 4 2 1
128 64 32 16 8 4 2 1
0 0 200 100 80 40 20 10
8 4 2 1 8 .4 .2 1
0 0 0 100 80 40 20 10
8 4 2 . .S 4 2 .
128 64 82 16 8 4 2 1
BYTES 287-536 AADAR ECHO
128 64 ,:2 16 8 4 2 1
128 64 32 16 8 4 2 1
128 64 32 16 8 4 2 1
0 0 200 100 80 40 20 10
8 4 2 1 .8 .4 .2 1
0 0 0 100 80 40 20 10
8 4 2 1 8 .4 .2 1
128 64 32 16 8 4 2 1
BYTES 547 - 795 RADAR ECHO
'28 64 32 10 8 4 2 I
128 64 32 10 8 4 2 .
128 64 32 10 8 4 2 1
0 0 200 100 80 40 20 10
8 4 " I .8 4 .2 I
0 0 (0 100 80 40 20 10
8 4 2 1 .8 .4 .2 1
.28 64 32 16 8 4 2 1
B'ITES 807-1056 RADAR ECHO
128 64 32 .6 8 4 2 1
128 64 32 16 8 4 2 1
128 64 32 16 8 4 2 I
//0 END OF RECORD GAP //

FRRME
(BYTE) FIELD
couln

I DAY OF YEAR
2 DAY OF YEAR
3 HOURS (C,U.T)
4 ~ll NUTES
5 SECONDS
6 '/EAR
7 RRNi3E DELAo.,'
8 LIN/lOO RECVR
9 BLUE S~}...
10 0
11 STATUS
12 I 0 CODE
13 RECORD COUNT
'4 RECORD cou~n
15 RECORD COUNT
.6
- BYTES (16 -
21 22) - '0'
22
23 AZ I NUTH
24 AZ I MUTH
25 ELEVAT I ON
26 ELEUAT I ON
27 QUIP, 81N 1
(O'JIP'S,
. BINS 2-250)
277 AIRCRAFT -I
278 A I RCRAFT -2
279 A I RCAAFT -3
280 <OVIPS,BINS
281 254-255
282 UNUSED)
283 AZ I MUTH
284 A2 I MlITH
285 ELEVAT I ON
280 ELElJAT I ON
287 DlJIP, BIN 1
288 <OVIP'S,
. Bins 2-250)
537 A I RCAAFT -1
538 A I ACAAFT -2
539 AIRCAAFT -3
540 <OUIPS,BINS
541 254-256
542 Uti USED )
543 AZ I MUTH
544 AZI MUTH
545 ELEVAT I ON
546 ELEUATI ON
547 OUIP, BIN'
548 <OUIP'S,
. BINS 2-250)
797 AIRCRAFT -1
798 A I RCRAFT -2
799 A I RCRAFT -3
800 <OU1PS,BINS
801 254 2'56
802 UNUSED)
803 AZI MUTH
804 AZ I MUTH
805 ELEUAT I ON
806 ELEUAT I ON
807 DUIP, Blti 1
808 <D1JIP'S,
. BINS 2-250)
1057 AIRCRAFT -I
1058 A I RCRAFT -2
1059 A I RCAAFT -3
1060 <OVIP'S,BINS
1061 254-256
1062 UNUSED)

1337

SWR - 86 RRORR
RRW DATA

TRPE FORMRT

STATUS FOAMAT
L/L RECE IVER
0 LOG
LINEAR
RHI
0 ON (RHI)
1 OFF (PPI)
AZ I MUTH
AI t NCREMENT
0.5
t ,0 DEG.
PULSE
REPET I T ION
PRF FREQUENCY
414
207 HZ
SRMPLES I
SA AVERAGE

o 0 8
o 1 16
1 0 32
1 1 64

RANGE
I MTERURL
RID I STANCE

o 0 0 125
o 0 1 .25
o 1 0 5
o 1 1 1
1 00 2 km

'" - NOTE> AES = RESERVED
EXCLUS I VEL Y FOR USE BY
ARCH r V I NG PROGAAM.

FIG. I. Magnetic tape format of raw data records
on SWR-86 radar.