SGLI Sensor Characterization

1. SGLI relative spectral response (RSR)

Liear scale figure

Log scale figure

Comparison with AHI and MODIS

Summary table of (average) center wavelength (WLc) and bandwidth (HW) [nm] (rev. 2014/10/20)
Band WLc[nm]HW[nm]TranW[nm]EXF0[W/m^2/um](Thuillier)F0[W/m^2/um](Kur)
VNL01379.853 10.7 3.0 4.1 1093.5379 1109.8123
VNL02412.306 10.4 3.2 3.8 1711.2835 1755.5305
VNL03443.433 10.2 3.0 3.9 1903.2471 1929.4749
VNL04489.686 10.4 2.8 4.3 1937.9540 1964.0677
VNL05529.638 19.7 5.0 4.6 1850.9682 1877.0691
VNL06565.926 19.9 5.1 4.6 1797.4827 1822.6236
VNL07672.002 22.3 5.2 5.0 1502.5522 1524.9353
VNL08672.148 22.1 5.3 4.9 1502.1799 1524.5890
VNL09762.917 11.4 3.8 3.6 1245.8937 1263.4791
VNL10866.835 21.1 6.0 4.1 956.2896 1005.4531
VNL11867.023 21.3 5.9 4.3 956.5311 1005.5876
VNN01380.030 10.7 3.1 4.1 1092.1436 1108.4976
VNN02412.514 10.4 3.2 3.8 1712.1531 1756.5108
VNN03443.240 10.2 3.0 3.9 1898.3185 1924.4533
VNN04489.849 10.4 2.8 4.3 1938.4602 1964.5807
VNN05529.640 19.7 5.1 4.6 1850.9604 1877.0611
VNN06566.155 20.1 5.0 4.7 1797.1344 1822.2721
VNN07671.996 22.3 5.2 5.0 1502.5667 1524.9477
VNN08672.098 22.1 5.2 4.9 1502.3177 1524.7151
VNN09763.074 11.4 3.7 3.6 1245.3663 1262.9589
VNN10866.765 21.1 6.1 4.1 956.2323 1005.5116
VNN11867.120 21.3 5.8 4.3 956.5352 1005.4458
VNR01380.212 10.7 3.1 4.1 1090.5931 1107.0316
VNR02412.589 10.4 3.2 3.8 1712.4760 1756.8697
VNR03443.051 10.2 3.0 3.9 1893.5879 1919.6334
VNR04490.311 10.4 2.8 4.3 1941.0715 1967.3261
VNR05529.664 19.7 5.0 4.6 1851.0657 1877.1674
VNR06566.377 20.1 5.0 4.7 1796.8275 1821.9625
VNR07671.950 22.3 5.2 5.0 1502.6962 1525.0681
VNR08672.120 22.1 5.3 4.9 1502.2582 1524.6613
VNR09763.234 11.4 3.8 3.6 1244.8290 1262.4288
VNR10866.713 21.1 6.0 4.1 956.2577 1005.5964
VNR11867.086 21.3 5.8 4.3 956.5735 1005.5181
VNP01671.892 20.9 6.0 4.1 1503.6050 1525.9627
VNP02866.180 20.3 5.6 4.2 956.8333 1007.5356
SWI011054.994 21.4 10.4 2.5 646.5213 652.4925
SWI021385.351 20.2 7.0 3.4 361.2250 354.9883
SWI031634.506 195.8 18.8 12.1 237.5784 232.5702
SWI042209.481 50.8 17.4 3.5 84.2413 81.3353
TIR0110793.5 763.2 210.6 4.3 0.0000 0.0000
TIR0211956.8 783.0 252.0 3.7 0.0000 0.0000
Approximation: RSR(W) = exp( log(1/2) * ( abs(W - WLc)/(HW/2) )^EX )
W: wavelength [nm]
TransW: Transition width [nm] from 0.1 to 0.8
F0 is calculated by Thuiller (2003) (at 1.0AU): GCOM-C standard irradiance
F0(Kur) is calculated by Kurucz (1992) (at 1.0AU)

Center wavelength of VNR-NP (telescope-L/N/R) and VNR-PL by normalized pixel number (-0.5 ~ +0.5) (rev. 2014/09/26, rev. 2014/10/23, rev. 2015/3/29 (POL), rev. 2015/12/25 (POL))

Coefficients c0~c4, regression error, Average, Min and Max of center wavelengths of VNL (VNR-NP telescope-Left), VNN (VNR-NP telescope-Nadir), VNR (VNR-NP telescope-Right) and VNR-PL (The coefficients were calculated by EORC using original measurements by SGLI sensor team) (rev. 2014/09/26, rev. 2014/10/23, rev. 2015/3/29 (POL), rev. 2015/12/25 (POL))
Bandc0 c1 c2 c3 c4 RgErr[nm]Ave[nm]Min[nm]Max[nm]
VNL013.7983E+02-2.0654E-014.0953E-017.6962E-01-7.5110E-010.005 379.85 379.80 379.91
VNL024.1235E+021.1515E-01-7.2607E-025.3384E-01-2.0197E+000.005 412.31 412.11 412.38
VNL034.4337E+029.0581E-026.3376E-015.5982E-027.0385E-020.004 443.43 443.37 443.57
VNL044.8966E+02-3.0622E-013.3672E-014.5020E-01-3.9824E-010.005 489.69 489.60 489.81
VNL055.2952E+02-3.5294E-019.6784E-01-3.1234E-011.9387E+000.011 529.62 529.47 530.08
VNL065.6589E+022.4046E-018.7851E-016.2411E-01-2.7019E+000.008 565.93 565.76 566.12
VNL076.7184E+02-3.4264E-017.7027E-01-6.1871E-015.8120E+000.020 671.98 671.81 672.61
VNL086.7201E+02-4.1357E-016.0967E-011.8496E-015.3048E+000.018 672.13 671.96 672.65
VNL097.6327E+023.1900E-01-2.6370E+00-1.6204E+00-4.7683E+000.008 762.96 762.35 763.28
VNL108.6738E+021.8538E+00-1.3750E+01-1.2301E+014.8520E+010.046 866.83 866.23 867.48
VNL118.6759E+021.8948E+00-1.3941E+01-1.2742E+014.8163E+010.042 867.02 866.40 867.70
VNN013.8001E+021.7104E-012.9402E-01-6.5029E-01-6.9351E-010.005 380.03 379.99 380.08
VNN024.1257E+021.6869E-01-2.2033E-014.3098E-01-1.9828E+000.008 412.52 412.28 412.60
VNN034.4316E+02-9.9156E-027.1108E-01-1.6487E-024.1156E-010.005 443.23 443.16 443.40
VNN044.8983E+022.8187E-012.9698E-01-3.6911E-01-5.8977E-010.005 489.85 489.77 489.97
VNN055.2952E+023.9348E-018.8587E-012.7552E-012.0914E+000.010 529.63 529.48 530.09
VNN065.6613E+022.9743E-017.9222E-014.1063E-01-2.9697E+000.007 566.16 565.96 566.34
VNN076.7182E+023.8590E-011.2226E+00-2.3696E-023.8871E+000.022 671.97 671.76 672.55
VNN086.7194E+024.3907E-017.5132E-012.2127E-025.3565E+000.018 672.08 671.89 672.66
VNN097.6342E+02-3.1793E-01-2.5845E+001.6389E+00-4.8441E+000.008 763.12 762.51 763.43
VNN108.6730E+02-1.7540E+00-1.3713E+011.2056E+014.8410E+010.045 866.76 866.18 867.43
VNN118.6767E+02-1.8758E+00-1.3568E+011.2824E+014.7018E+010.032 867.12 866.50 867.81
VNR013.8020E+02-1.4418E-012.5644E-016.5340E-01-9.4438E-010.006 380.21 380.18 380.24
VNR024.1265E+022.0817E-01-3.2323E-013.4006E-01-1.7034E+000.006 412.60 412.34 412.68
VNR034.4296E+021.0681E-018.1284E-01-3.6629E-027.1595E-010.004 443.04 442.96 443.24
VNR044.9032E+02-2.2237E-011.0639E-022.1432E-01-5.0950E-010.007 490.31 490.21 490.39
VNR055.2955E+02-4.1437E-019.1150E-01-1.2109E-011.6420E+000.011 529.65 529.50 530.09
VNR065.6636E+023.4432E-017.4963E-012.2421E-01-3.3094E+000.006 566.38 566.16 566.56
VNR076.7177E+02-4.0534E-011.1152E+00-1.8236E-014.7486E+000.018 671.93 671.73 672.55
VNR086.7198E+02-5.0520E-016.5910E-012.4386E-015.1359E+000.017 672.10 671.91 672.67
VNR097.6357E+023.0504E-01-2.5451E+00-1.5900E+00-4.8479E+000.007 763.28 762.68 763.58
VNR108.6725E+021.7793E+00-1.3803E+01-1.2226E+014.9354E+010.048 866.71 866.11 867.44
VNR118.6760E+022.0163E+00-1.3424E+01-1.4051E+014.8480E+010.034 867.08 866.46 867.90
VNP016.7191e+02-3.3244e-011.2376e+011.2811e+00-3.2838e+010.023672.54671.89673.10
VNP028.6620e+02-1.7438e+001.0498e+005.1759e+00-5.6396e+000.007866.22865.85866.63
WLc[nm]=c0 +c1*X +c2*X^2 +c3*X^3 +c4* X^4
X (= -0.5 ~ +0.5): (pixels - center_pixel)/pixel_length
pixels: 1~pixel_length at a telescope
pixel_length=1500 (VNR-NP 250m), pixel_length=857 (VNR-PL)
c0: center wavelength at the telescope center (X=0)

[these equations or the above conversion tables are recommended]
(optimized for 130K~400K)


From SGLI-band Radiance (RD) to SGLI-band Brightness temperature (BT) by SGLI center wavelength (WL)
BT0 =c2 /WL /log(c1/RD/WL^5 +1);
BT[K] =cr2t(1) +cr2t(2)*BT0 +cr2t(3)*BT0^2;

From SGLI-band Brightness temperature (BT) to SGLI-band Radiance (RD) by SGLI center wavelength (WL)
RD0 =c1 /WL^5 /(exp(c2/WL/BT) -1);
RD[W/m^2/str/um] =ct2r(1) +ct2r(2)*RD0 +ct2r(3)*RD0^2;

Constants (same as Himawari-8):
c =299792458;
h =6.62606957E-34;
k =1.38064880E-23;
c1=2*h*c^2 *1.0E+24;
c2=(h*c)/(k *1.0E-6);

TIR01:
WL[um]=10.7935
cr2t=[-3.6658555409e-01, 1.0032838274e+00, -6.0965021334e-06];
ct2r=[-3.2302206075e-01, 1.0031652102e+00, -6.3965619878e-06];

TIR02:
WL[um]=11.9568
cr2t=[-2.7185709007e-04, 9.9843659844e-01, 6.1836121620e-05];
ct2r=[-4.9968999113e-04, 9.9866962896e-01, 8.0654962709e-05];

(BT->Radiance or Radiance->BT table should be used for precise calculations; see aboves)
Upper panel shows brightness temperature (BT) and Radiance relation
Light blue: TIR01 (10.7935 um), Red: TIR02 (11.9568 um)
Lower panel shows BT error due to monochromatic approximation:
Radiance[W/m^2/str/um] = 119104286.8142 / WL[um]^5 / ( exp( 14387.7696 / WL[um] / BT[K] ) - 1);
WL: center wavelength [um] (= wavelength [nm] *0.001)
BT: Brightness Temperature [K]
- TIR01 center wavelength (white weight): 10.7935um, RMSE=0.0522[K]
- TIR02 center wavelength (white weight): 11.9568um, RMSE=0.0497[K]
-- TIR01 minimum error wavelength: 10.7939um, RMSE=0.0521[K]
-- TIR02 minimum error wavelength: 11.9555um, RMSE=0.0485[K]

2. Signal to Noise Ratio (SNR)

  • SNR at Lstd (VN09:1km, others:250m)
  • BandNPLNPNNPRLstd(W/m2/sr/um)
    VN0165967569260
    VN0282678678975
    VN0348753153264
    VN0485887086853
    VN0546852245741
    VN0610641038101733
    VN071006101398823
    VN0853756454625
    VN0917461592160040
    VN105104704938
    VN1150451147830
  • SNR at Lstd (1km)
  • Pol 60 0 -60Lstd(W/m2/sr/um)
    PL0164370761425
    PL0264676376030
  • SNR at Lstd (SW03:250m, others:1km)
  • BandSRU-ASRU-BLstd(W/m2/sr/um)
    SW0195193757
    SW023463378
    SW031001033
    SW043793811.9
  • NEdT(K) (500m)
  • BandSRU-ASRU-BNEdT(K)
    TIR10.0390.038300
    TIR20.0690.065300

    3. Polarization sensitivity

    4. Stray light (TBD)