Improvements on global meteorological observations from the current Fengyun 3 satellites and beyond

Figures & data

Figure 1.  Current Chinese meteorological satellites in orbit.

Table 1. List of launched Chinese meteorological satellites.

Satellite name	Satellite type	Launch date	Satellite function
FY-1A	Polar	7 September 1988	R&D
FY-1B	Polar	3 September 1990	R&D
FY-1C	Polar	10 May 1999	Operation
FY-1D	Polar	15 May 2002	Operation
FY-3A	Polar	27 May 2008	R&D
FY-3B	Polar	5 November 2010	R&D
FY-2A	Geostationary	10 June 1997	R&D
FY-2B	Geostationary	25 June 2000	R&D
FY-2C	Geostationary	18 October 2004	Out of lifetime
FY-2D	Geostationary	8 December 2006	Operation
FY-2E	Geostationary	23 December 2008	Operation
R&D, research and development satellites.

Table 2. Major technical specifications of the FY-3 platform.

Parameters	Technical specifications
Launch mass	≤2450 kg
Dimensions
Ground configuration	4380 mm×2000 mm×2000 mm (X.Y.Z)
On orbit configuration	4440 mm×10000 mm×3790 mm (X.Y.Z)
Orbit	Sun-synchronous, near-polar circular
Nominal orbit altitude	836 km
Nominal orbit inclination	98.75°
Orbit period	101.49 min
Eccentricity	≤0.003
Number of revolutions/day	14.17
Repeat cycle	about 5 days
Local time at descending/ascending node	10:00~10:20 (FY-3A) 13:40~14:00 (FY-3B)
Local time drift at descending/ascending node	Less than 15 min. in 2 years
Payload instruments	11
On-board data storage	144 GB
Data transmission
Real time	L band; QPSK modulation; 4.2 Mbps bit rate
	X band; QPSK modulation; 18.7 Mbps bit rate
Delayed transmission	X band; QPSK modulation; 93 Mbps bit rate
Attitude
Control	3-axis stabilized
Control accuracy	≤0.3° (X,Y,Z)
Measurement accuracy	≤0.05° (X,Y,Z)
Stability	≤0.004°/s (X,Y,Z)
Designed life time	3 years

Table 3. Specifications of the 11 payloads.

Name	Specification		Purpose
Imager
VIRR	Spectral range	0.43−12.5 µm	Cloud image, cirrus and cloud phase, vegetation, sediment, snow and ice, land surface temperature, sea surface temperature, water vapor content
	Number of channels	10
	Scan range	±55.4°
	Spatial resolution at nadir	1.1 km
	Cal accuracy in VNIR	5%−10%
	Cal Accuracy in IR	1 K(270 K)
	Quantization	10 bits
MERSI	Spectral range	0.40−12.5 µm	Ocean color, aerosol, water vapor content, cloud properties, vegetation, surface properties, surface temperature, snow and ice
	Number of channels	20
	Scan range	±55.2°
	Spatial resolution at nadir	0.25−1 km
	Cal accuracy in VNIR	5%−10%
	Cal accuracy in IR	1 K(270 K)
	Quantization	12 bits
MWRI	Spectral range	10−89 GHz	Precipitation rate, liquid water content, water vapor content, soil moisture, sea ice, sea surface temperature, snow cover, ice cover
	Number of channels	10
	Scan range	45.0°
	Spatial resolution at nadir	15−85 km
	Cal accuracy	1−2.8 K
	Quantization	12 bits
Sounder
IRAS	Spectral range	0.69−15.0 µm	Atmospheric temperature profile, atmospheric moisture profile, total ozone amount, outgoing longwave radiation
	Number of channels	26
	Scan range	±49.5°
	Spatial resolution at nadir	17 km
	Cal accuracy in VNIR	5%−9%
	Cal accuracy in IR	1 K (270 K)
	Quantization	13 bits
MWTS	Spectral range	50−57 GHz
	Number of channels	4
	Scan range	±48.3°
	Spatial resolution at nadir	50−75 km
	Cal accuracy	1.2 k
	Sensitivity (NE▵N)	0.4−0.55 k
	Quantization	13 bits
MWHS	Spectral range	150−183 GHz
	Number of channels	5
	Scan range	±53.35°
	Spatial resolution at nadir	15 km
	Cal accuracy	1.5 k
	Sensitivity (NE▵N)	1.1–1.2 k
	Quantization	14 bits
Ozone
SBUS	Spectral range	0.16−0.4 µm	Ozone profile
	Number of channels	12
	Spatial resolution at nadir	200 km
	Quantization	16 bits
	Stray light	10^−6
	Cal accuracy	3% (160−250 nm) 2% (250−400 nm)
	Cal accuracy in diffuse reflection board	3%
TOU	Spectral range	0.3−0.36 µm	Total ozone amount
	Number of channels	6
	Scan range	±55.8°
	Spatial resolution at nadir	50 km
	Quantization	12 bits
	Stray light	10^−5
	Cal accuracy	2%
Radiation
ERM	Spectral range		Terrestrial radiation
	Total band	0.2−50 µm
	Solar band	0.2−3.8 µm
	Number of channels
	Narrow FOV	2
	Broad FOV	2
	Scan range	±50°(narrow)
	Sensitivity (NE▵N)	0.4 Wm^−2·sr^−1
	Cal accuracy
	Total band	0.8%
	Solar band	1%
	Stability within 2 years	<0.02%
SIM	Spectral range	0.2−50 µm	Solar irradiation
	Sensitivity (NE▵N)	0.2 Wm^−2
	Cal accuracy	0.5%
	Quantization	16 bits
	Stability within 2 years	<0.02%
SEM	Heavy ions, high energy proton, high energy electron, radiation dose, satellite surface charging monitoring, single event upset		Space environment

Figure 2.  Standard deviations of bias-corrected first-guess departures for FY-3A and MetOp-A/AQUA equivalent instruments and channels (Courtesy of Lu Qifeng, NSMC). Statistics are derived from data used in the period from 28 August to 28 September, 2008: (a) MWTS and AMSU-A, (b) MWHS and MHS, (c) IRAS and HIRS, and (d) MWRI and AMSR-E.

Figure 3.  Global total column ozone distribution monitored by TOU/FY-3A (a), GOME 2/Metop (b), and OMI/Aura (c) (Courtesy of Wang Weihe, NSMC).

Figure 4.  Global radiative anomalies in shortwave and longwave derived from ERM/FY-3 in an El Niño year (2010) and La Niña year (2011). (a) Shortwave radiative anomalies in an El Niño year (2010), (b) shortwave radiative anomalies in an La Niña year (2011), (c) longwave radiative anomalies in an El Niño year (2010), and (d) longwave radiative anomalies in a La Niña year (2011) (Courtesy of Zhang Yan and Qiu Hong, NSMC).

Table 4. Scheduled instruments on board FY-3C and beyond.

	Satellites
Scheduled instruments	FY-3C 2012	FY-3D 2014	FY-3E 2017	FY-3F 2019
MERSI – Medium resolution spectral imager (I, II)	√(I)	√(II)	√(II)	√( II)
MWTS – Microwave temperature sounder (II)	√	√	√	√
MWHS – Microwave humidity sounder (II)	√	√	√	√
MWRI – Microwave radiation imager	√	√		√
WindRAD – Wind radar			√
GAS – Greenhouse gases absorption spectrometer		√		√
HIRAS – Hyperspectral infrared atmospheric sounder		√	√	√
OMS – Ozone mapping spectrometer			√
GNOS – GNSS occultation sounder	√	√	√	√
ERM – Earth radiation measurement (I, II)	√(I)		√(II)
SIM – Solar irritation monitor (I, II)	√(I)		√(II)
SES – Space environment suite	√	√	√	√
IRAS – Infrared atmospheric sounder	√
VIRR – Visible and infrared radiometer	√
SBUS – Solar backscattered ultraviolet sounder	√
TOU – Total ozone unit	√