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Operational Calibration of the Imagers and Sounders
|
Channel | M | B |
---|---|---|
2 | 227.3889 | 68.2167 |
3 | 38.8383 | 29.1287 |
4 | 5.2285 | 15.6854 |
5 | 5.0273 | 15.3332 |
Channel | M | B |
---|---|---|
1 | 528.9773 | 1745.625 |
2 | 540.0049 | 1566.014 |
3 | 485.6243 | 1311.186 |
4 | 394.5752 | 887.7943 |
5 | 357.8019 | 787.1643 |
6 | 334.1747 | 417.7184 |
7 | 311.5226 | 249.2180 |
8 | 314.6032 | 251.6826 |
9 | 434.3518 | 716.6805 |
10 | 1126.224 | 900.9795 |
11 | 1899.565 | 1139.739 |
12 | 2874.342 | 2155.757 |
13 | 9642.747 | 626.7785 |
14 | 14105.38 | 916.8496 |
15 | 26221.34 | 1704.387 |
16 | 10720.60 | 428.8239 |
17 | 12136.11 | 497.5806 |
18 | 19358.13 | 348.4463 |
To convert radiance to temperature, one first uses the following formula (the inverse of the Planck function) to derive "effective" temperature:
Teff = (c2n)/ln(1 + [c1n3]/R) ,
where Teff is effective temperature (K), "ln" stands for natural logarithm, and R is radiance. The coefficients c1 and c2 are the two radiation constants, given by
c1 = 1.191066x10-5 mW/(m2-sr-cm-4)
c2 = 1.438833 K/cm-1
The quantity n is the central wavenumber of the channel. For a given channel it may vary slightly among detectors, and it will vary from instrument to instrument. The values of appear in tables A3-A6.
To convert effective temperature Teff to actual temperature T (K), one uses the following formula:
T = bTeff + a,
The constants n, a, and b and depend on channel, detector, and instrument and appear in Tables A3-A6.
The use of Teff accounts for the variation of the Planck function across the spectral passband of the channel. The differences between the values of T and Teff increase with decreasing temperature. They are usually of the order of 0.1K. In the worst case, near 180K, they are approximately 0.3K.
The mode - A count value Xa is derived from the temperature with the following equations15:
For 163K <= T <= 242K, Xa = 418 - T.
For 242K <= T <= 330K, Xa = 660 - 2T.
Mode-A count values are on an eight-bit scale and range in value from 0 to 255, with high counts representative of low temperatures. Beyond the difference in precision, there is a fundamental difference between GVAR counts and mode-A counts--their units. GVAR counts are scaled radiances, whereas mode-A counts are temperatures.
Tables of GVAR counts, radiances, temperatures, and mode-A counts will be provided by the first author on request.
Channel | Detector | n(cm-1) | a(K) | b |
---|---|---|---|---|
2 | 1 | 2556.71 | -0.578526 | 1.001512 |
2 | 2 | 2558.62 | -0.581853 | 1.001532 |
3 | 1 | 1481.91 | -0.593903 | 1.001418 |
4 | 1 | 934.30 | -0.322585 | 1.001271 |
4 | 2 | 935.38 | -0.351889 | 1.001293 |
5 | 1 | 837.06 | -0.422571 | 1.001170 |
5 | 2 | 837.00 | -0.466954 | 1.001257 |
Channel | Detector | n(cm-1) | a(K) | b |
---|---|---|---|---|
2 | 1 | 2555.18 | -0.579908 | 1.000942 |
2 | 2 | 2555.18 | -0.579908 | 1.000942 |
3 | 1 | 1481.82 | -0.493016 | 1.001076 |
4 | 1 | 934.59 | -0.384798 | 1.001293 |
4 | 2 | 934.28 | -0.363703 | 1.001272 |
5 | 1 | 834.02 | -0.302995 | 1.000941 |
5 | 2 | 834.09 | -0.306838 | 1.000948 |
Channel | Detector | n(cm-1) | a(K) | b |
---|---|---|---|---|
1 | 1 | 680.59705 | 0.0011541479 | 1.0000183 |
1 | 2 | 680.51139 | 0.0047380732 | 1.0000086 |
1 | 3 | 680.81462 | 0.0014610959 | 1.000018 |
1 | 4 | 680.73182 | -0.00042293612 | 1.0000216 |
2 | 1 | 695.92447 | -0.067530673 | 1.0001987 |
2 | 2 | 695.93168 | -0.069026616 | 1.0002026 |
2 | 3 | 696.1214 | -0.073060464 | 1.0002117 |
2 | 4 | 695.8373 | -0.056595405 | 1.0001696 |
3 | 1 | 711.80216 | -0.010171243 | 1.0000582 |
3 | 2 | 711.8637 | -0.015032924 | 1.0000701 |
3 | 3 | 711.96416 | -0.011705031 | 1.0000615 |
3 | 4 | 711.80891 | -0.011002261 | 1.0000614 |
4 | 1 | 732.48438 | -0.0042959367 | 1.0000392 |
4 | 2 | 732.39916 | -0.0040822167 | 1.0000379 |
4 | 3 | 732.46298 | -0.0051373478 | 1.0000106 |
4 | 4 | 732.46931 | -0.0049827181 | 1.0000101 |
5 | 1 | 747.75312 | -0.037536733 | 1.0001166 |
5 | 2 | 747.53399 | -0.031523095 | 1.0001032 |
5 | 3 | 747.59143 | -0.031117282 | 1.0001025 |
5 | 4 | 747.48321 | -0.022986702 | 1.0000855 |
6 | 1 | 790.5998 | -0.09722985 | 1.0002888 |
6 | 2 | 790.39692 | -0.093920988 | 1.0002841 |
6 | 3 | 790.35717 | -0.089752097 | 1.0002749 |
6 | 4 | 791.35802 | -0.13292141 | 1.0003539 |
7 | 1 | 827.63841 | -0.0232754 | 1.0003278 |
7 | 2 | 830.40346 | -0.19918135 | 1.0006315 |
7 | 3 | 829.32451 | -0.13434617 | 1.0005204 |
7 | 4 | 827.61148 | 0.017236714 | 1.0002605 |
8 | 1 | 906.81053 | -0.15212177 | 1.0004685 |
8 | 2 | 906.20913 | -0.15912377 | 1.0004923 |
8 | 3 | 906.91478 | -0.18977748 | 1.0005115 |
8 | 4 | 907.56109 | -0.2034948 | 1.0005222 |
9 | 1 | 1029.7209 | -0.045072033 | 1.0001371 |
9 | 2 | 1029.6963 | -0.043802031 | 1.000135 |
9 | 3 | 1029.2687 | -0.033910527 | 1.0001365 |
9 | 4 | 1029.3769 | -0.035802096 | 1.0001361 |
10 | 1 | 1339.7687 | -0.15379456 | 1.0003742 |
10 | 2 | 1339.2473 | -0.14469896 | 1.0003929 |
10 | 3 | 1339.5185 | -0.14680066 | 1.0003878 |
10 | 4 | 1339.5473 | -0.14827852 | 1.0003824 |
11 | 1 | 1421.09 | -0.23363311 | 1.0007483 |
11 | 2 | 1421.8586 | -0.24877913 | 1.0006982 |
11 | 3 | 1420.6829 | -0.21459881 | 1.0007938 |
11 | 4 | 1422.4471 | -0.26186387 | 1.0006938 |
12 | 1 | 1536.2837 | -0.16825513 | 1.000216 |
12 | 2 | 1535.3069 | -014374678 | 1.0002864 |
12 | 3 | 1537.5272 | -0.23662459 | 1.0000769 |
12 | 4 | 1535.0548 | -0.16469406 | 1.0002578 |
13 | 1 | 2184.7961 | -0.01849728 | 1.0000665 |
13 | 2 | 2184.7961 | -0.01849728 | 1.0000665 |
13 | 3 | 2184.7961 | -0.01849728 | 1.0000665 |
13 | 4 | 2184.7961 | -0.01849728 | 1.0000665 |
14 | 1 | 2207.5585 | -0.023929612 | 1.0000191 |
14 | 2 | 2207.5585 | -0.023929612 | 1.0000191 |
14 | 3 | 2207.5585 | -0.023929612 | 1.0000191 |
14 | 4 | 2207.5585 | -0.023929612 | 1.0000191 |
15 | 1 | 2247.5698 | -0.034093166 | 0.99993075 |
15 | 2 | 2247.5698 | -0.034093166 | 0.99993075 |
15 | 3 | 2247.5698 | -0.034093166 | 0.99993075 |
15 | 4 | 2247.5698 | -0.034093166 | 0.99993075 |
16 | 1 | 2422.0784 | -0.066306989 | 1.000011 |
16 | 2 | 2422.0784 | -0.066306989 | 1.000011 |
16 | 3 | 2422.0784 | -0.066306989 | 1.000011 |
16 | 4 | 2422.0784 | -0.066306989 | 1.000011 |
17 | 1 | 2509.4001 | -0.060780208 | 1.0001174 |
17 | 2 | 2509.4001 | -0.060780208 | 1.0001174 |
17 | 3 | 2509.4001 | -0.060780208 | 1.0001174 |
17 | 4 | 2509.4001 | -0.060780208 | 1.0001174 |
18 | 1 | 2664.7035 | -0.34148389 | 1.0009243 |
18 | 2 | 2664.7035 | -0.34148389 | 1.0009243 |
18 | 3 | 2664.7035 | -0.34148389 | 1.0009243 |
18 | 4 | 2664.7035 | -0.34148389 | 1.0009243 |
Channel | Detector | n(cm-1) | a(K) | b |
---|---|---|---|---|
1 | 1 | 681.53264 | -0.061569679 | 1.0001824 |
1 | 2 | 681.40135 | -0.053410761 | 1.0001603 |
1 | 3 | 681.52794 | -0.090823775 | 1.0002626 |
1 | 4 | 681.23907 | -0.049632175 | 1.0001508 |
2 | 1 | 694.26673 | -0.035721417 | 1.0001135 |
2 | 2 | 694.09261 | -0.026237608 | 1.0000894 |
2 | 3 | 693.93184 | -0.014017787 | 1.0000574 |
2 | 4 | 694.11597 | -0.026341654 | 1.0000893 |
3 | 1 | 711.39629 | -0.043973934 | 1.0001314 |
3 | 2 | 711.25223 | -0.035778771 | 1.0001112 |
3 | 3 | 711.00519 | -0.026554312 | 1.0000877 |
3 | 4 | 711.07759 | -0.025028536 | 1.0000841 |
4 | 1 | 732.56429 | -0.031778653 | 1.0000973 |
4 | 2 | 732.50229 | -0.028546325 | 1.0000897 |
4 | 3 | 732.50527 | -0.032654323 | 1.0000997 |
4 | 4 | 732.33055 | -0.025780988 | 1.0000829 |
5 | 1 | 747.19713 | -0.043470631 | 1.0001236 |
5 | 2 | 747.1825 | -0.04211854 | 1.0001205 |
5 | 3 | 746.83467 | -0.020193021 | 1.0000714 |
5 | 4 | 746.91053 | -0.03125795 | 1.0000972 |
6 | 1 | 789.55684 | -0.065385221 | 1.0002199 |
6 | 2 | 789.72841 | -0.072530803 | 1.0002344 |
6 | 3 | 789.84766 | -0.080716615 | 1.0002493 |
6 | 4 | 789.35098 | -0.056105065 | 1.0001998 |
7 | 1 | 826.87703 | 0.041396369 | 1.000228 |
7 | 2 | 827.22901 | 0.0274577 | 1.0002501 |
7 | 3 | 828.27187 | -0.087133142 | 1.000445 |
7 | 4 | 828.67767 | -0.069590619 | 1.0004218 |
8 | 1 | 911.22294 | -0.30550413 | 1.0006317 |
8 | 2 | 910.73052 | -0.28258246 | 1.0006113 |
8 | 3 | 909.80214 | -0.23979418 | 1.0005719 |
8 | 4 | 909.70281 | -0.22061492 | 1.0005457 |
9 | 1 | 1028.9077 | -0.058287786 | 1.0001362 |
9 | 2 | 1028.8798 | -0.054285716 | 1.0001341 |
9 | 3 | 1028.7845 | -0.055189391 | 1.000134 |
9 | 4 | 1028.8579 | -0.055101679 | 1.0001342 |
10 | 1 | 1335.2658 | -0.1131839 | 1.0004206 |
10 | 2 | 1335.8313 | -0.13015363 | 1.0003907 |
10 | 3 | 1336.0503 | -0.13414168 | 1.0003834 |
10 | 4 | 1335.8627 | -0.1304702 | 1.0003901 |
11 | 1 | 1420.8469 | -0.2383551 | 1.0007496 |
11 | 2 | 1421.0338 | -0.24007956 | 1.0007414 |
11 | 3 | 1420.6599 | -0.23051649 | 1.0007729 |
11 | 4 | 1420.7697 | -0.23480823 | 1.000752 |
12 | 1 | 1529.1783 | -0.18721929 | 1.000148 |
12 | 2 | 1529.4056 | -0.19578939 | 1.0001144 |
12 | 3 | 1529.2363 | -0.17817533 | 1.0001506 |
12 | 4 | 1529.6935 | -0.20017465 | 1.0001009 |
13 | 1 | 2183.9199 | -0.019638376 | 1.0000246 |
13 | 2 | 2183.9199 | -0.019638376 | 1.0000246 |
13 | 3 | 2183.9199 | -0.019638376 | 1.0000246 |
13 | 4 | 2183.9199 | -0.019638376 | 1.0000246 |
14 | 1 | 2207.0082 | -0.024176572 | 0.99999895 |
14 | 2 | 2207.0082 | -0.024176572 | 0.99999895 |
14 | 3 | 2207.0082 | -0.024176572 | 0.99999895 |
14 | 4 | 2207.0082 | -0.024176572 | 0.99999895 |
15 | 1 | 2245.837 | -0.029091526 | 0.99994699 |
15 | 2 | 2245.837 | -0.029091526 | 0.99994699 |
15 | 3 | 2245.837 | -0.029091526 | 0.99994699 |
15 | 4 | 2245.837 | -0.029091526 | 0.99994699 |
16 | 1 | 2415.1642 | -0.051874656 | 1.000095 |
16 | 2 | 2415.1642 | -0.051874656 | 1.000095 |
16 | 3 | 2415.1642 | -0.051874656 | 1.000095 |
16 | 4 | 2415.1642 | -0.051874656 | 1.000095 |
17 | 1 | 2512.0862 | -0.063295056 | 1.0000751 |
17 | 2 | 2512.0862 | -0.063295056 | 1.0000751 |
17 | 3 | 2512.0862 | -0.063295056 | 1.0000751 |
17 | 4 | 2512.0862 | -0.063295056 | 1.0000751 |
18 | 1 | 2665.3491 | -0.28151318 | 1.0007142 |
18 | 2 | 2665.3491 | -0.28151318 | 1.0007142 |
18 | 3 | 2665.3491 | -0.28151318 | 1.0007142 |
18 | 4 | 2665.3491 | -0.28151318 | 1.0007142 |
Next | Previous | Table of Contents
Contact Michael P. Weinreb at michael.weinreb@noaa.gov
Latest Revision: July 9, 1997