Autonomous vicarious calibration based on automated test-site radiometer

刚刚 邱; 新 李; 小兵 郑; 静 闫; 彦港 孙

doi:10.3788/COL201614.121201

Chinese Optics Letters, Volume. 14, Issue 12, 121201(2016)

Autonomous vicarious calibration based on automated test-site radiometer

刚刚邱^1,2, 新李^1、*, 小兵郑^1、**, 静闫¹, and 彦港孙³

¹Key Laboratory of Optical Calibration and Characterization, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China

²University of Sciences and Technology of China, Hefei 230031, China

³Shanghai Maritime University, Shanghai 201306, China

show less

Figures & Tables(8)

Fig. 1. AVCS. (a) ATR, (b) Cimel sunphotometer, and (c) automated diffuser-to-globe irradiance meter.

Download full size

View in Article

Fig. 2. (a) The reflectance curves in the central area of CRCS (10 km×10 km) from an analytical spectral device (ASD) field spectrometer at August 13–22, 2015. (b) The relative root mean square (RMS) deviation of the surface reflectance at the central area is in a range that is less than 2% than 350–500 nm and less than 1% from 500–2500 nm. (c) The reflectance curves of 11 measured points, from the SVC, in the 200 m×200 m square area near the ATR on August 19, 2015. (d) The RMS deviation of reflectance is less than 3.4% within the whole band.

Download full size

View in Article

Fig. 3. Surface reflectance versus wavelength for Dunhuang Gobi on August 19, 2015 and the NSR of the ATR and MODIS. The surface reflectance was obtained by personnel using an SVC. A standard panel is used as a reflectance standard during this measurement.

Download full size

View in Article

Table 1. Calibration Results by Traditional Approach

View table

View in Article

Table 1. Calibration Results by Traditional Approach

AQUA/MODIS	Predicted radiance ( $W \cdot {(m^{2} \cdot sr \cdot μ m)}^{- 1}$ )	MODIS radiance ( $W \cdot {(m^{2} \cdot sr \cdot μ m)}^{- 1}$ )	Percent difference (%)
Band 1	99.137	98.330	0.819
Band 2	65.804	65.107	1.071
Band 3	107.867	108.577	−0.653
Band 4	102.444	103.013	−0.552

Table 2. Parameter at Overpass Time

View table

View in Article

Table 2. Parameter at Overpass Time

Parameter	Aqua	Terra
Overpass time (Beijing)	14:36	12:57
Viewing zenith (deg.)	25.35	27.88
Viewing azimuth (deg.)	77.03	283.39
Solar zenith (deg.)	30.05	29.87
Solar azimuth (deg.)	205.30	155.61
Water column ( $grams / {cm}^{2}$ )	0.9768	0.9768
Ozone column (Dobson units)	297	297
AOD550	0.2269	0.2297
Day of year	233	233
Earth-sun distance (A.U.)	0.95438	0.95438
Air temperature (°C)	30.0	31.3
Relative humidity (%)	10.2	9.1
Pressure (mBar)	870.2	869.0

Table 3. Predicted and AQUA/MODIS TOA Radiance Comparison

View table

View in Article

Table 3. Predicted and AQUA/MODIS TOA Radiance Comparison

AQUA/MODIS	Predicted radiance ( $W \cdot {(m^{2} \cdot sr \cdot μ m)}^{- 1}$ )	MODIS radiance ( $W \cdot {(m^{2} \cdot sr \cdot μ m)}^{- 1}$ )	Relative difference (%)
Band 1	93.713	96.466	−2.853
Band 2	61.204	64.379	−4.933
Band 3	104.529	105.734	−1.140
Band 4	97.830	100.612	−2.764

Table 4. Predicted and TERRA/MODIS TOA Radiance Comparison

View table

View in Article

Table 4. Predicted and TERRA/MODIS TOA Radiance Comparison

TERRA/MODIS	Predicted radiance ( $W \cdot {(m^{2} \cdot sr \cdot μ m)}^{- 1}$ )	MODIS radiance ( $W \cdot {(m^{2} \cdot sr \cdot μ m)}^{- 1}$ )	Relative difference (%)
Band 1	94.292	93.862	0.458
Band 2	60.923	63.065	−3.395
Band 3	104.843	108.297	−3.189
Band 4	97.975	100.194	−2.214

Table 5. Uncertainty of AORC
View table
View in Article
Table 5. Uncertainty of AORC
Error sources Uncertainty (%)
Surface reflectance measurement 4.3
AOD 2.1
Model atmosphere 1.7
Radiometric transmission model 1.0
Non-Lambert 1.5
Solar zenith angle 2.0
Water vapor 2.2
Total 6.2