ESA - Living Planet Programme - MetOp - AMSU-A1 channels

Instruments - AMSU-A1

AMSU-A1 channels

The Advanced Microwave Sounding Unit (AMSU-A1) consists of twelve V-band channels (3 - 14) and one W-band channel 15 and associated circuitry. It has two scanning reflectors: the lower antenna (farthest from Earth in flight) is designated A1-1 and provides inputs to channels 6 and 7, and channels 9 - 15; the upper antenna (closest to Earth in flight) designated A1-2 provides input to channels 3 - 5 and 8.

At each channel frequency, the antenna beamwidth is a constant 3.33° ± 10% (circular, at half power point). Thirty contiguous resolution scenes are sampled in a stepped-scan fashion every eight seconds.

AMSU-A1 radiometer characteristics are illustrated in the table below:

Centre frequency (MHz) Bandwidth (MHz) Centre frequency stability (MHz)
3 50300 180
(2 pass-bands) ± 10.0
4 52800 400
(2 pass-bands) ± 5.0
5 53596 ± 115 170
(2 pass-bands) ± 5.0
6 54400 400
(2 pass-bands) ± 5.0
7 54940 400
(2 pass-bands) ± 5.0
8 55500 330
(2 pass-bands) ± 10.0
9 57290.344 = F_lo 330
(2 pass-bands) ± 0.5
10 F_lo ± 217 MHz 78
(2 pass-bands) ± 0.5
11 F_lo ± 322.2 MHz ± 48 MHz 36
(4 pass-bands) ± 1.2
12 F_lo ± 322.2 MHz ± 22 MHz 16
(4 pass-bands) ± 1.2
13 F_lo ± 322.2 MHz ± 10 MHz 8
(4 pass-bands) ± 0.5
14 F_lo ± 322.2 MHz ± 4.5 MHz 3
(4 pass-bands) ± 0.5
15 89.0 GHz 3000
(2 pass-bands) ± 130.0

Temperature sensitivity
NEDT (K) Calibration Accuracy (K) Polarization -3 dB Stop Band (SB) f_c ± SB (MHz)
3 0.4 1.5 V 10.0
4 0.25 1.5 V 10.0
5 0.25 1.5 H 30.0
6 0.25 1.5 H 10.0
7 0.25 1.5 V 10.0
8 0.25 1.5 H 10.0
9 0.25 1.5 H 10.0
10 0.4 1.5 H 178.0
11 0.4 1.5 H 256.2
12 0.6 1.5 H 292.2
13 0.8 1.5 H 308.2
14 1.2 1.5 H 316.2
15 0.5 2.0 V 500.0

V : Polarization vector is parallel to scan plane at nadir
H : Polarization vector is perpendicular to scan plane at nadir

Last update: 28 June 2006

In depth

• About AMSU-A1 (http://www.esa.int/esaLP/SEMAHGG23IE_LPmetop_0.html)
• Components (http://www.esa.int/esaLP/ESAGPIVTYWC_LPmetop_0.html)
• Products (http://www.esa.int/esaLP/ESA3BFVTYWC_LPmetop_0.html)

MetOp's instruments

• A/DCS (http://www.esa.int/esaLP/SEM3JGG23IE_LPmetop_0.html)
• AMSU-A1 (http://www.esa.int/esaLP/SEMAHGG23IE_LPmetop_0.html)
• AMSU-A2 (http://www.esa.int/esaLP/SEMIFGG23IE_LPmetop_0.html)
• ASCAT (http://www.esa.int/esaLP/SEMBWEG23IE_LPmetop_0.html)
• AVHRR (http://www.esa.int/esaLP/SEM9VEG23IE_LPmetop_0.html)
• GOME-2 (http://www.esa.int/esaLP/SEMTTEG23IE_LPmetop_0.html)
• GRAS (http://www.esa.int/esaLP/SEMTSEG23IE_LPmetop_0.html)
• HIRS (http://www.esa.int/esaLP/SEMUREG23IE_LPmetop_0.html)
• IASI (http://www.esa.int/esaLP/SEMNQEG23IE_LPmetop_0.html)
• MHS (http://www.esa.int/esaLP/SEM7ADG23IE_LPmetop_0.html)
• SARP-3 (http://www.esa.int/esaLP/SEMV4DG23IE_LPmetop_0.html)
• SARR (http://www.esa.int/esaLP/SEMU2DG23IE_LPmetop_0.html)
• SEM (http://www.esa.int/esaLP/SEMD1DG23IE_LPmetop_0.html)