NOAA KLM User's Guide

Appendix J

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APPENDIX J: Instrument Scan Properties

Each instrument onboard the NOAA KLM and NOAA-N,N'series of spacecraft has it's own unique scanning properties. This appendix contains a table of parameters (Table J-1) for the scanning instruments on the TIROS-N through NOAA-14 series (the TIROS-N series), and a table for the instruments on NOAA KLM and NOAA-N,N'(Table J-2). It should be noted that the AVHRR instrument scans from the anti-Sun side to the Sun side; i.e., from right to left when facing in the direction of satellite motion. All other instruments scan in the opposite direction.

The SEM and DCS/2 instruments have not been included in this appendix, because neither instrument scans. The SEM has fixed FOVs and the DCS/2 is a passive instrument acting as a transponder. Technically, the SBUV/2 instrument does not scan, but is a nadir viewing instrument. However, a brief section (J.4) is included describing how it looks at the earth through a sequence of 12 wavelength changes.

In addition, this appendix contains a section for each instrument with figures showing the scan motion.

Table J-1. Satellite Scanning Instrument Parameters for TIROS-N through NOAA-14.
Parameter AVHRR/2 HIRS/2 & 2I
(see Note 7)
SSU MSU
IFOV (Degrees) 0.0745 HIRS/2: 1.22
HIRS/2I: 1.40
10 7.5
Full scan period (seconds) 0.1667 6.4 32 25.6
Earth View
Total number of earth view steps 2048 56 8 11
center to center FOV step angle (Degrees) 0.0541 1.8 10 9.4737
Max scan angle (Degrees from Nadir to the center of outer earth FOV) 55.37 49.5 35 47.3685
Total earth view time (msec) 51.2 5600
(see Note 1)
32000
(see Note 6)
20823
FOV integration time + dead time (msec)
(See Note 8)
0.025 100 4000 1893
Integration period/FOV (msec) 0.025 Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
3600 1820
Initial offset time from TIP to start of integration period (msec) (see Note 4) 2.529 20.4 400 0
Difference between the TIP start to center of integration period of first FOV (msec) 2.5415 23.0 2200 910
Rotational rate during integration 6 cycles/sec 0 0 0
Space View
Space view time (msec) 0.250 4800
(see Note 2)
15600
(see Note 6)
1820
Number of samples 10 48 4 1
Integration time/sample (msec) 0.025 Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
3600 1820
Total integration time (msec) 0.250 216 14400 1820
Internal Calibration Target (ICT) View(s)
Internal calibration target(s) view time (msec) 0.250 Cold: 5600
(see Note 3)

Warm: 5600
(see Note 3)
15600
(see Note 6)
1820
Number of samples 10 56 4 1
Integration time/sample (msec) 0.025 4.5 3600 1820
Total integration time (msec) 0.250 256 14400 1820
Ground Resolution (see Note 5)
IFOV diameter at nadir (km) 1.1 HIRS/2: 17.7
HIRS/2I: 20.4
147.5 109.9
IFOV at center of outer FOV (km) 6.2 x 2.3 HIRS/2: 59.5 x 30.4
HIRS/2I: 68.3 x 34.8
243.9 x 183.4 356.4 x 175.8
Half Swath Width (see Note 5)
Nadir to center of outer FOV (km) 1460.2 HIRS/2: 1089.4
HIRS/2I: 1089.4
604.2 816.8
Nadir to far edge of outer FOV (km) 1463.3 HIRS/2: 1119.8
HIRS/2I: 1124.4
736.3 1173.2
Notes:

1 The earth view steps rapidly, then holds at each position while the 20 filter segments are sampled. Multispectral data from one visible, seven shortwave, and twelve longwave are obtained.

2 The space views position is held while the 20 filter segments are sampled 48 sequential times.

3 The ICT view positions are held while the 20 filter segments are sampled 56 sequential times.

4 Time offsets from TIP first major frame time to the center of the first FOV when all instruments are at the beginning of scan (every 128 seconds).

5 All earth dimensions are based on a 833 km height above a spherical earth of radius 6371.22 km.

6 The space and ICT view sequences are performed every 256 seconds and last 32 seconds. This is followed by 7 cycles of earth view sequences (each lasting 32 seconds).

7 HIRS/2I was flown on NOAA-14 only.

8 Dead time is defined as the non-integration time needed for reflector slewing and/or transferring of data.

Table J-2. NOAA Satellite Scanning Instrument Parameters for NOAA KLM and NOAA-N,N'.
Parameter AVHRR/3 HIRS/3 HIRS/4 AMSU MHS
-A1 -A2 -B
IFOV (Degrees) 0.0745 1.40 0.69 3.3 3.3 1.1 1.1
Full scan period (seconds) 0.1667 6.4 6.4 8 8 2.67 2.67
Earth View
Total number of earth view steps 2048 56 56 30 30 90 90
FOV Step angle (Degrees) 0.0541
(see Note 6)
1.8 1.8 31/3 31/3 1.1 1.1111
Max scan angle (Degrees from Nadir to the center of outer earth FOV) 55.37
(see Note 6)
49.5 49.5 48.33 48.33 48.95 49.4444
Total earth view time (msec) 51.2 5600
(see Note 1)
5600
(see Note 1)
6075 6075 1620 1710
FOV integration time + dead time (msec)
(see Note 7)
0.025 100 100 202.5 202.5 19 19
Integration period/FOV (msec) 0.025 Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
165 158 18 19
Initial offset time from TIP to start of integration period
(msec) (see Note 4)
2.529 20.4 20.4 3.55 3.26 -9 -38
(see Note 8)
Difference between the TIP to center of integration period of first FOV (msec) 2.5415 23.0 23 86.05 82.26 9 -28.5
Rotational rate during integration 6 cycles/sec 0 0 0 0 1 rad/sec 1 rad/sec
Space View
Space view time (msec) 0.250 4800
(see Note 2)
4800
(see Note 2)
365 365 75 76
Number of integration samples 10 48 48 2 2 4 4
Integration time (msec) 0.025 Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
165 158 18 19
Total integration time (msec) 0.250 216 216 330 316 72 76
Internal Calibration Target (ICT) View
Internal calibration target view time (msec) 0.250 5600
(see Note 3)
5600
(see Note 3)
365 365 75 76
Number of integration dwells 10 56 56 2 2 4 4
Integration time/dwell (msec) 0.025 Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
Channel 1=5.1;
Channels 2-12=1.8;
Channels 13-20=4.5.
165 158 18 19
Total integration time (msec) 0.250 252 252 330 316 72 76
Ground Resolution (see Note 5)
IFOV diameter at nadir (km) 1.1 20.4 10.2 48.05 48.05 16.0 16
IFOV at center of outer FOV (km) 6.24 x 2.3 68.3 x 34.8 34.15 x 17.4 149.1 x 79.4 149.1 x 79.4 51.6 x 26.9 51.6 x 26.9
Half Swath Width (see Note 5)
Nadir to center of outer FOV (km) 1460.2 1089.4 1089.4 1034.8 1034.8 1063.1 ?
Nadir to far edge of outer FOV (km) 1463.3 1124.4 1107.325 1113.4 1113.4 1089.4 ?
Notes:

1. The earth view steps rapidly, then holds at each position while the 20 filter segments are sampled. Multispectral data from one visible, seven shortwave, and twelve longwave are obtained.

2. The space views position is held while the 20 filter segments are sampled 48 sequential times.

3. The ICT view position are held while the 20 filter segments are sampled 56 sequential times.

4. Time offsets from TIP first major frame time to the center of the first FOV when all instruments are at the beginning of scan (every 128 seconds).

5. All earth dimensions are based on a 833 km height above a spherical earth of radius 6371.22 km.

6. NOAA-16 has a max scan angle of 55.25 degrees with a step angle of 0.053981436 degrees.

7. Dead time is defined as the non-integration time needed for reflector slewing and/or transferring of data.

8. MHS data is delayed 2 scan periods for data handling overhead prior to the TIP time stamp.

Amended November 21, 2000

Amended November 6, 2001

Amended November 2, 2005

Amended December 13, 2005


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