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INFRARED ABSORPTION

By Charles Rhodes, P. Eng., Ph.D.

GLOSSARY OF TERMS

OVERVIEW OF INFRARED ABSORPTION:
For an overview of absorption of radiation by gaseous molecules please refer to:
CRISP
 

THE ROLE OF INFRARED ABSORPTION:
Recall from the Radiation Physics section that the emission temperature of an element of surface area of the earth is given by:
Ta = Te [(1 - Fr) / Ft]^.25
where the emissivity Ft is measured in the infrared spectral range and the albedo Fr is measured in the solar spectral range. Recall also that:
Ft = Integral from Z = 0 to Z = infinity of:
{Ftw(W) [15/Pi^4] Z^3 dZ / [exp(Z) - 1]}
where Z = (h F) / (K Ta)

In order to understand Ftw(W) it is necessary to understand the infrared absorption characteristics of the greenhouse gases and how these gases affect the infrared spectrum of the earth. The gases of most interest are water vapor, carbon dioxide, ozone, methane and nitrous oxide.
 

VIEW FROM OUTER SPACE:
When the earth is viewed from outer space with an infrared thermal emission spectrometer, the recorded spectrum consists of radiation from species that will readily interact with electromagnetic radiation. Oxygen and nitrogen do not interact with photons in the thermal emission spectral range and hence are not seen. Water vapor, which interacts with photons almost right across the thermal emission spectrum is seen, as are carbon dioxide and ozone. High resolution thermal emission spectroscopy equipment for satelite use is being developed.

The following Tropical Clear Sky thermal emission spectrum was recorded by an IRIS instrument (Infra Red Interferometer Spectrometer) on board a Nimbus-3 or Nimbus-4 satelite over the tropical central Pacific Ocean on an exceptionally clear day when there was almost no cloud in its 100 km wide field of view. This spectrum is undated but the satelite mission records indicate that this spectrum was recorded either in the time interval April 14, 1969 to July 22, 1969 or in the time interval April 18, 1970 to January 30, 1971.

Satelite References:
IRIS Description
Spectral Range of IRIS on Nimbus 4 satelite
Nimbus 3 IRIS Operational April 14, 1969 to July 22, 1969, Nimbus 4 IRIS Operational April 8, 1970 to April 14, 1971
NIMBUS 4 IRIS data good until January 30, 1971
Nimbus 3 IRIS Spectral Resolution = 5cm^-1, Nimbus 4 IRIS Spectral Resolution = 1.4 cm^-1
High resolution thermal emission spectroscopy equipment for satelite use
Consolidation of 9268 IRIS thermal IR spectra for the equatorial ocean published in Ph.D. thesis of Xianglei Huang, April 2004, pages 3 to 6, 14, 35 and 47.

This spectrum also shows the width (575 cm^-1 to 775 cm^-1) of the main carbon dioxide absorption band over the equitorial Pacific Ocean in 1970 as seen by the overhead satelite with minimum interference by water vapor.

For wavenumbers less than 400 cm^-1 and greater than 1300 cm^-1 even a small amount of water vapor obscures everything else. The above plot also shows a dark green 255 K black body line corresponding to the temperature of high altitude water vapor.

In the wavenumber band 996 cm^-1 to 1068 cm^-1 ozone in the upper atmosphere obscures the water vapor. At wavenumbers 1029 cm^-1 and 1054 cm^-1 an overhead satelite sees radiation of an intensity corresponding to the temperature of the ozone layer.

At a wavenumber of 669 cm^-1 carbon dioxide has a much stronger absorption than water vapor. Hence, when the earth is viewed from a satelite through 669 cm^-1 bandpass filter the carbon dioxide in the upper atmosphere obscures the water vapor from the satelite's view. Since the upper atmosphere is cold (215 K), that is the effective temperature seen by the satelite at 669 cm^-1.

In the wavenumber ranges 850 cm^-1 to 980 cm^-1 and 1080 cm^-1 to 1200 cm^-1 a dense cloud of water vapor will prevent infrared radiation originating below the cloud from reaching a spacecraft above the atmosphere. Hence the spacecraft sees the temperature at the top of the cloud.

On a clear day when there is almost no cloud the remaining water vapor is almost transparent in the wavenumber range 475 cm^-1 to 1200 cm^-1. Under these circumstances within this wavenumber range the satelite can see almost down to ground level, except within the carbon dioxide and ozone absorption bands. The satelite sees condensing water vapor above the surface of the ocean. Near the equator the equivalent black body temperature seen by the satelite is in the range 265 degrees K to 285 degrees K, depending on the season. This spectral band is known as the 'water vapor window". This band allows infrared emission to space from warm water vapor regions near the warm ocean surface. This relatively high temperature thermal emission carries away most of the Earth's thermal radiant energy, thus keeping the Earth cool. Increased obstruction of the "water window" by carbon dioxide absorption leads to an increase in the Earth's surface temperature.

Careful examination of the thermal emission spectrum recorded by the IRIS instrument reveals carbon dioxide side band absorption lines at 515 cm^-1, 548 cm^-1, 800 cm^-1 and 850 cm^-1, outside the main carbon dioxide absorption band but between 475 cm^-1 and 875 cm^-1. These side bands likely arise due to rotation of the CO2 molecule. Amplitude modulation theory indicates that there will be an infinite series of such side bands with diminishing amplitude away from the center frequency. The side band absorption lines become much more important at larger carbon dioxide concentrations.

The IRIS data shows that within the wavenumber range 400 cm^-1 to 1600 cm^-1, at the present atmospheric carbon dioxide concentration, there is no significant carbon dioxide gas absorption outside the 475 cm^-1 to 875 cm^-1 band.

Laboratory measurements of infrared absorption by carbon dioxide show that the carbon dioxide absorption band consists of a central strong absorption line at 669 cm^-1 (wavelength = 15 um) and a series of side bands of diminishing amplitude. Increasing the concentration of carbon dioxide in the measurement apparatus increases the strength of the absorption sidebands and hence effectively increases the width of the carbon dioxide absorption band.

In the Earth's atmosphere the central absorption band is saturated, but the side bands are not. Increasing the atmospheric CO2 concentration brings more CO2 absorption side bands into play. On Earth the atmospheric CO2 pressure is about .000387 bar. Experimental evidence from the planet Venus indicates that a its atmospheric CO2 pressure of about 90 bars causes a temperature increase of about 400 degrees C.

Although the above IR spectrum reveals a lot of useful information it cannot be used for global warming calculations because it is representative of nearly ideal cloudless conditions, not average conditions, and the value of Fr is not known for these nearly ideal conditions.
 

INFRARED ABSORPTION DATA:
Infrared Absorbance Data for water vapor, carbon dioxide, ozone, methane and nitrous oxide is available in both graphical and numerical form from the NIST Chemistry WebBook. This data is helpful for identifying the infrared absorption lines for each gas. For further background information it is helpful to refer to:
Content and Basic Properties of the Atmosphere and Infrared Spectroscopy
 

WATER VAPOR:
The physical structure of a water (H2O) molecule causes it to have a very complex families of rotational and vibrational states. The molecule is Vee shaped because the two hydrogen atoms bond to each other as well as bonding to the oxygen atom.

Chemically each of the two hydrogen atoms give up one electron to the oxygen atom, causing the oxygen atom to be negatively charged andt the hydrogen atoms to be positively charged. The mass of the hydrogen atoms is small compared to the mass of the oxygen atom, so the center of mass is located near the oxygen atom and the rotational moment of inertia is small. The moment of inertia is different in each of the three planes of rotation. Quantization of angular momentum leads to a wide range of rotational states forming absorption lines in the wavenumber range 200 cm^-1 to 600 cm^-1.(50 um to 16.6 um)

There are also vibrational states relating to the hydrogen-oxygen chemical bond. The interacion between the two hydrogen atoms massively complicates these vibrational states. These vibrational states form a broad absorption band in the frequency range start 1300 cm^-1 to 1900 cm^-1 (7.7 um to 5.2 um). This absorption band has an extremely narrow passband at about 1600 cm^-1.

Between the rotational states and the vibrational states Water vapor (H2O) has an infrared passband that extends from 600 cm^-1 to 1300 cm^-1 (20 um to 7.7 um).

The two water vopor absorption bands cut off the high wavenumber and low wavenumber ends of the infrared thermal emission spectrum emitted by the earth. Water vapor also has weak wideband absorption. Experimental data shows that increasing the water vapor concentration in the atmosphere increases the altitude at which the thermal emission occurs, and vice versa. It is possible that this wide band absorption is related to H2CO3 formed by combination of CO2 disolving in H20 cloud droplets. The exact physical mechanism of this wide band absorption remains to be resolved.

At any particular location the water vapor concentration goes through daily oscillations due to the rotation of the earth. The average water vapor concentration seeks a level that minimizes energy related to the daily water vapor concentration oscillations. The water vapor concentration adopts a level where the fluctuations in (1 - Fr) due to water vapor cancel out the fluctuations in Ft due to water vapor. Thus the temperature remains relatively constant and water is a moderating influence.

Recall that greenhouse warming is given by:
(Ta - Te) / Te = {[(1 - Fr) / Ft]^.25 - 1}
The effect of adding an increment of water vapor to the atmosphere is to increase albedo Fr and to decrease Ft. As the concentration of water vapor in the atmosphere increases the albedo increases which in turn reduces the amount of absorbed solar power, which reduces the rate of water evaporation. On average the rate of water evaporation matches the rate of precipitation. The rate of precipitation is set by the rate of infrared radiative cooling by the atmosphere. In the above equation these two effects cancel one another.

The effect of clouds is to moderate daily temperature swings because clouds reduce absorbed solar radiation during the day and trap infrared radiation during the night. When the atmospheric temperature is very low the water vapor concentration in the atmosphere is low, so there are relatively large daily temperature swings.

The concentration of water vapor in the atmosphere cannot be directly controlled by mankind. Water vapor goes through a phase change and tends to establish its own equilibrium.

Shown below is experimental relative infrared absorbance data published by NIST. The left hand column gives the wavenumber in cm^-1. The other columns give the absorbance results of ten successive experimental spectrum scans for the wavenumber range 450 cm^-1 to 2000 cm^-1. The far right column gives the average of the ten experimental runs in the spectral range of immediate interest.

NIST INFRARED ABSORPTION DATA FOR WATER VAPOR

WAVENUMBER(cm^-1)    ABSORBANCE                                   AVERAGE
450.0 97 1808 4679 1749 1382 2926 3112 759 1423 1682              1961.7
490.0 1555 1702 629 2741 1616 1569 1561 3208 1300 1338            1721.9
530.0 808 573 990 321 1352 1070 761 533 514 614                   753.6
570.0 900 1242 898 1368 791 1050 508 1035 612 602                 900.6
610.0 220 635 512 580 896 348 858 752 769 322    water window     589.2
650.0 460 377 458 476 213 791 325 454 201 615    water window     437.0
690.0 564 696 528 474 586 409 409 321 364 306    water window     465.7
730.0 400 259 373 476 535 310 480 340 241 418    water window     383.2
770.0 280 396 282 465 236 363 363 455 405 309    water window     355.4
810.0 467 235 399 256 405 228 340 359 277 349    water window     331.5
850.0 314 485 239 403 298 371 258 379 326 281    water window     335.4
890.0 377 310 370 247 443 294 376 306 405 324    water window
930.0 314 408 298 377 270 447 259 381 328 368    Water window
970.0 334 338 405 268 389 301 406 271 396 340    water window
1010.0 336 368 349 383 258 415 308 401 282 436   water window
1050.0 327 355 383 356 388 317 445 295 409 312   water window
1090.0 427 314 371 405 348 400 314 451 282 427   water window
1130.0 331 401 388 375 411 324 440 338 434 308   water window
1170.0 457 446 406 377 435 446 298 491 325 423   water window
1210.0 345 594 355 420 589 363 411 320 619 355   water window
1250.0 485 326 595 563 692 1090 542 496 478 893  water window
1290.0 862 883 547 522 324 1074 1519 2362 1220 678
1330.0 600 532 3686 2833 728 790 704 1606 2872 2101
1370.0 1377 3107 2174 943 2379 2016 3150 4455 2166 1526
1410.0 2525 403 6621 2679 3121 1234 4221 3423 1319 1350
1450.0 2363 3847 7480 3681 2250 2293 6614 4690 716 3528
1490.0 6097 2708 4544 3680 7523 10000 6087 7143 9633 5270
1530.0 5613 4122 6153 9560 7220 3325 4233 8971 5018 2175
1570.0 2909 2683 1973 2028 0 1274 540 1556 447 1294      narrow passband
1610.0 1430 989 3843 1317 3926 208 3423 3912 1967 2813
1650.0 6727 6477 2700 1834 2373 3100 5484 1568 5970 6742
1690.0 3409 2173 7444 6751 4878 1930 4049 7816 2728 905
1730.0 3154 7275 3233 2933 4399 5718 3197 3042 3036 1605
1770.0 3910 4492 1879 2542 2083 2709 3470 2649 3801 1188
1810.0 1606 1831 813 1478 2069 2935 1620 638 2226 3508
1850.0 1629 298 798 777 1724 3134 871 425 497 790
1890.0 1363 1145 687 515 662 846 1050 1188 1942 711
1930.0 350 506 369 1454 1081 345 379 527 277 951
1970.0 636 325 280 296 206 1183 1035 404 252 328
2010.0 176 524 878 526 267 310 129 403 563 352

Note the water window from 600 cm^-1 to 1300 cm^-1 and the very narrow passband between 1570 cm^-1 and 1610 cm^-1.  The width of this passband is less than the 40 cm^-1 incrementation of the digitized spectrum.

 

CARBON DIOXIDE:
From a global warming perspective the most important gas is carbon dioxide. Its laboratory measured relative transmittance versus:
Wavenumber= F / C
for five experimental runs is tabulated below using data from NIST. The claimed resolution is 4 cm^-1.


FREQUENCY (cm^-1) TRANSMITTANCE
             #1     #2     #3     #4     #5
458.879000 0.9730 0.9730 0.9720 0.9720 0.9720
463.551912 0.9720 0.9730 0.9730 0.9730 0.9730
468.224824 0.9750 0.9750 0.9760 0.9760 0.9780
472.897735 0.9780 0.9780 0.9790 0.9790 0.9790
477.570647 0.9790 0.9790 0.9780 0.9780 0.9760
482.243559 0.9760 0.9750 0.9750 0.9750 0.9750
486.916471 0.9750 0.9750 0.9750 0.9750 0.9750
491.589383 0.9750 0.9750 0.9750 0.9730 0.9730
496.262295 0.9730 0.9730 0.9730 0.9730 0.9710
500.935206 0.9710 0.9710 0.9690 0.9690 0.9690
505.608118 0.9690 0.9680 0.9660 0.9660 0.9660
510.281030 0.9650 0.9630 0.9630 0.9630 0.9620
514.953942 0.9620 0.9620 0.9620 0.9630 0.9630 Weak Sideband 515 = 669-(3X51.3)
519.626854 0.9650 0.9650 0.9660 0.9660 0.9660
524.299766 0.9660 0.9660 0.9660 0.9650 0.9650
528.972677 0.9650 0.9650 0.9650 0.9650 0.9650
533.645589 0.9650 0.9650 0.9650 0.9650 0.9650
538.318501 0.9650 0.9660 0.9660 0.9660 0.9650
542.991413 0.9650 0.9650 0.9630 0.9630 0.9630
547.664325 0.9620 0.9620 0.9620 0.9620 0.9620 Weak Sideband 548 = 650 -(2X51)
552.337236 0.9620 0.9630 0.9630 0.9650 0.9650
557.010148 0.9660 0.9660 0.9680 0.9690 0.9690
561.683060 0.9710 0.9710 0.9720 0.9720 0.9730   
566.355972 0.9730 0.9730 0.9730 0.9750 0.9750
571.028884 0.9750 0.9750 0.9760 0.9760 0.9760
575.701796 0.9780 0.9780 0.9780 0.9780 0.9760
580.374707 0.9760 0.9750 0.9750 0.9730 0.9730
585.047619 0.9730 0.9730 0.9720 0.9710 0.9690
589.720531 0.9690 0.9680 0.9650 0.9630 0.9620   
594.393443 0.9600 0.9590 0.9580 0.9560 0.9470
599.066355 0.9290 0.9080 0.9080 0.9290 0.9420  Sideband 599 = 650 - 51
603.739266 0.9400 0.9390 0.9360 0.9340 0.9340
608.412178 0.9330 0.9320 0.9330 0.9340 0.9360
613.085090 0.9360 0.9360 0.9390 0.9420 0.9450
617.758002 0.9430 0.9288 0.4711 0.4650 0.5749  Narrow 618 = 669 - 51
622.430914 0.9443 0.9470 0.9470 0.9261 0.9141
627.103826 0.9030 0.8850 0.8740 0.8560 0.8380
631.776737 0.8061 0.7781 0.7631 0.7441 0.7231
636.449649 0.7020 0.6800 0.6570 0.6340 0.6120
641.122561 0.5891 0.5671 0.5401 0.5340 0.5181
645.795473 0.5080 0.4979 0.4460 0.4010 0.3520
650.468385 0.3031 0.3030 0.3608 0.3550 0.3490   STRONG SIDEBAND 650 = 669 - 9
655.141297 0.3450 0.3420 0.3430 0.3480 0.3490
659.814208 0.3560 0.3620 0.3680 0.3750 0.3780
664.487120 0.3850 0.4200 0.4660 0.4630 0.1993   Relative Minimum Absorption
669.160032 0.1341 0.0692 0.1797 0.2737 0.2939   MAXIMUM ABSORPTION 669
673.832944 0.2990 0.2940 0.2900 0.2860 0.2810   Relative Minimum Absorption
678.505856 0.2800 0.2800 0.2810 0.2900 0.2990   Strong Sideband 678 = 669 + 9
683.178767 0.3060 0.3150 0.3230 0.3260 0.3350
687.851679 0.3430 0.3540 0.3670 0.3799 0.3949    
692.524591 0.4110 0.4290 0.4450 0.4620 0.4790
697.197503 0.4950 0.5100 0.5359 0.5490 0.5819
701.870415 0.6110 0.6310 0.6630 0.6800 0.6970     
706.543327 0.7130 0.7389 0.7520 0.7610 0.7829
711.216238 0.8090 0.8330 0.8490 0.8560 0.8690
715.889150 0.8770 0.8900 0.9109 0.9210 0.9300
720.562062 0.8149 0.7099 0.5790 0.3332 0.3330    Narrow Sideband 720 = 669 +51
725.234974 0.9578 0.9580 0.9550 0.9460 0.9430
729.907886 0.9390 0.9360 0.9330 0.9320 0.9300    
734.580797 0.9290 0.9290 0.9270 0.9270 0.9260
739.253709 0.9260 0.9260 0.9240 0.9230 0.9210 Sideband 739 = 669 + 51 + 9
743.926621 0.9230 0.9370 0.9460 0.9580 0.9600
748.599533 0.9630 0.9650 0.9680 0.9690 0.9730
753.272445 0.9760 0.9780 0.9790 0.9810 0.9820
757.945357 0.9820 0.9840 0.9840 0.9850 0.9860
762.618268 0.9860 0.9880 0.9890 0.9890 0.9890
767.291180 0.9890 0.9890 0.9890 0.9890 0.9890
771.964092 0.9910 0.9910 0.9910 0.9910 0.9910
776.637004 0.9910 0.9910 0.9910 0.9910 0.9920
781.309916 0.9920 0.9910 0.9910 0.9890 0.9890
785.982828 0.9890 0.9890 0.9890 0.9890 0.9890   Weaker
790.655739 0.9890 0.9890 0.9890 0.9890 0.9890   Weaker  
795.328651 0.9890 0.9890 0.9890 0.9890 0.9880   Weaker   
800.001563 0.9880 0.9860 0.9860 0.9860 0.9860   Weak Sideband 800
804.674475 0.9880 0.9880 0.9880 0.9880 0.9880   Weaker   
809.347387 0.9890 0.9890 0.9890 0.9890 0.9890   Weaker  
814.020298 0.9890 0.9910 0.9910 0.9910 0.9910
818.693210 0.9910 0.9910 0.9910 0.9910 0.9910
823.366122 0.9910 0.9910 0.9910 0.9910 0.9920
828.039034 0.9920 0.9920 0.9920 0.9910 0.9910
832.711946 0.9910 0.9920 0.9920 0.9920 0.9920
837.384858 0.9920 0.9920 0.9920 0.9920 0.9940
842.057769 0.9940 0.9940 0.9940 0.9940 0.9940
846.730681 0.9940 0.9940 0.9940 0.9940 0.9950
851.403593 0.9950 0.9940 0.9940 0.9940 0.9940
856.076505 0.9940 0.9940 0.9940 0.9950 0.9940  weak sideband 856
860.749417 0.9940 0.9940 0.9940 0.9940 0.9940
865.422328 0.9940 0.9940 0.9950 0.9950 0.9950
870.095240 0.9950 0.9950 0.9950 0.9950 0.9950
874.768152 0.9950 0.9950 0.9950 0.9950 0.9950
879.441064 0.9950 0.9950 0.9950 0.9950 0.9950
884.113976 0.9970 0.9970 0.9950 0.9950 0.9950
888.786888 0.9950 0.9950 0.9940 0.9940 0.9940 weak sideband
893.459799 0.9950 0.9950 0.9950 0.9950 0.9950 weak sideband
898.132711 0.9970 0.9950 0.9950 0.9950 0.9950 weak
902.805623 0.9950 0.9950 0.9950 0.9970 0.9970
907.478535 0.9970 0.9980 0.9980 0.9980 1.0000
912.151447 1.0000 1.0010 1.0010 1.0010 1.0010
916.824359 1.0010 1.0010 1.0010 1.0010 1.0020
921.497270 1.0020 1.0020 1.0020 1.0020 1.0020
926.170182 1.0020 1.0020 1.0040 1.0040 1.0040
930.843094 1.0040 1.0040 1.0040 1.0040 1.0040
935.516006 1.0040 1.0040 1.0050 1.0050 1.0050
940.188918 1.0050 1.0050 1.0050 1.0050 1.0050
944.861829 1.0050 1.0050 1.0050 1.0050 1.0050
949.534741 1.0050 1.0050 1.0050 1.0050 1.0050
954.207653 1.0050 1.0050 1.0050 1.0050 1.0050
958.880565 1.0050 1.0050 1.0050 1.0050 1.0050
963.553477 1.0050 1.0050 1.0050 1.0070 1.0070
968.226389 1.0070 1.0070 1.0070 1.0070 1.0070
972.899300 1.0070 1.0070 1.0070 1.0070 1.0080
977.572212 1.0080 1.0070 1.0070 1.0070 1.0070
982.245124 1.0070 1.0070 1.0070 1.0070 1.0070
986.918036 1.0070 1.0070 1.0070 1.0080 1.0080
991.590948 1.0080 1.0080 1.0100 1.0100 1.0100
996.263860 1.0100 1.0080 1.0080 1.0080 1.0080
1000.936771 1.0080 1.0070 1.0070 1.0050 1.0050
1005.609683 1.0040 1.0040 1.0040 1.0050 1.0070      absorption 1005
1010.282595 1.0080 1.0080 1.0100 1.0100 1.0100
1014.955507 1.0100 1.0110 1.0110 1.0110 1.0130
1019.628419 1.0130 1.0140 1.0140 1.0140 1.0140
1024.301330 1.0140 1.0140 1.0140 1.0140 1.0140
1028.974242 1.0140 1.0150 1.0150 1.0150 1.0150
1033.647154 1.0150 1.0150 1.0150 1.0150 1.0150
1038.320066 1.0150 1.0140 1.0140 1.0130 1.0130
1042.992978 1.0110 1.0110 1.0110 1.0110 1.0140      absorption 1042
1047.665890 1.0150 1.0150 1.0140 1.0050 1.0020      absorption 1047
1052.338801 1.0040 1.0140 1.0150 1.0150 1.0130
1057.011713 1.0130 1.0130 1.0140 1.0140 1.0140
1061.684625 1.0130 1.0130 1.0130 1.0130 1.0110
1066.357537 1.0110 1.0110 1.0100 1.0080 1.0050
1071.030449 1.0050 1.0040 1.0040 1.0040 1.0040
1075.703360 1.0040 1.0050 1.0050 1.0080 1.0080
1080.376272 1.0100 1.0110 1.0110 1.0110 1.0130
1085.049184 1.0130 1.0130 1.0140 1.0140 1.0140
1089.722096 1.0140 1.0140 1.0140 1.0150 1.0150
1094.395008 1.0150 1.0150 1.0150 1.0170 1.0170
1099.067920 1.0170 1.0170 1.0170 1.0170 1.0170
1103.740831 1.0170 1.0170 1.0170 1.0170 1.0170
1108.413743 1.0170 1.0170 1.0170 1.0170 1.0170
1113.086655 1.0180 1.0180 1.0180 1.0180 1.0180
1117.759567 1.0180 1.0180 1.0180 1.0180 1.0180
1122.432479 1.0180 1.0180 1.0180 1.0180 1.0180
1127.105391 1.0170 1.0170 1.0170 1.0170 1.0150
1131.778302 1.0140 1.0140 1.0140 1.0130 1.0130
1136.451214 1.0130 1.0130 1.0110 1.0110 1.0110
1141.124126 1.0110 1.0110 1.0130 1.0130 1.0140
1145.797038 1.0140 1.0150 1.0150 1.0150 1.0150
1150.469950 1.0170 1.0170 1.0180 1.0180 1.0180
1155.142861 1.0180 1.0180 1.0180 1.0180 1.0180
1159.815773 1.0180 1.0180 1.0180 1.0180 1.0180
1164.488685 1.0180 1.0180 1.0180 1.0180 1.0180
1169.161597 1.0180 1.0180 1.0180 1.0180 1.0180
1173.834509 1.0170 1.0150 1.0140 1.0140 1.0130
1178.507421 1.0110 1.0100 1.0100 1.0110 1.0140
1183.180332 1.0170 1.0170 1.0180 1.0180 1.0200
1187.853244 1.0200 1.0200 1.0210 1.0210 1.0230
1192.526156 1.0230 1.0230 1.0230 1.0230 1.0230
1197.199068 1.0230 1.0230 1.0230 1.0230 1.0230
1201.871980 1.0230 1.0230 1.0230 1.0230 1.0230
1206.544891 1.0230 1.0230 1.0230 1.0230 1.0230
1211.217803 1.0230 1.0230 1.0230 1.0230 1.0230
1215.890715 1.0230 1.0230 1.0230 1.0230 1.0230
1220.563627 1.0210 1.0210 1.0210 1.0210 1.0200
1225.236539 1.0200 1.0200 1.0200 1.0200 1.0200
1229.909451 1.0200 1.0210 1.0200 1.0200 1.0180
1234.582362 1.0180 1.0170 1.0150 1.0150 1.0140
1239.255274 1.0130 1.0100 1.0100 1.0080 1.0080
1243.928186 1.0080 1.0070 1.0070 1.0050 1.0050
1248.601098 1.0050 1.0040 1.0040 1.0020 1.0020
1253.274010 1.0010 1.0010 1.0010 1.0010 1.0010
1257.946922 1.0010 1.0010 1.0010 1.0010 1.0000
1262.619833 1.0000 1.0000 1.0000 1.0000 1.0000
1267.292745 1.0000 1.0000 1.0000 1.0000 1.0000
1271.965657 0.9980 0.9980 0.9980 0.9980 0.9980
1276.638569 0.9980 0.9980 0.9980 0.9980 0.9970
1281.311481 0.9970 0.9970 0.9970 0.9970 0.9970
1285.984392 0.9970 0.9970 0.9970 0.9950 0.9950
1290.657304 0.9940 0.9940 0.9940 0.9940 0.9940
1295.330216 0.9940 0.9940 0.9940 0.9940 0.9940
1300.003128 0.9940 0.9940 0.9940 0.9940 0.9940
1304.676040 0.9950 0.9950 0.9950 0.9950 0.9950
1309.348952 0.9950 0.9950 0.9950 0.9950 0.9950
1314.021863 0.9940 0.9940 0.9940 0.9920 0.9940
1318.694775 0.9940 0.9940 0.9940 0.9940 0.9940
1323.367687 0.9940 0.9950 0.9950 0.9950 0.9950
1328.040599 0.9950 0.9950 0.9950 0.9950 0.9950
1332.713511 0.9950 0.9950 0.9950 0.9950 0.9950
1337.386422 0.9950 0.9950 0.9950 0.9950 0.9950
1342.059334 0.9950 0.9950 0.9950 0.9950 0.9970
1346.732246 0.9970 0.9950 0.9950 0.9940 0.9940
1351.405158 0.9920 0.9910 0.9890 0.9880 0.9860
1356.078070 0.9860 0.9850 0.9850 0.9840 0.9840
1360.750982 0.9840 0.9840 0.9850 0.9850 0.9850
1365.423893 0.9850 0.9860 0.9860 0.9850 0.9840
1370.096805 0.9820 0.9820 0.9820 0.9810 0.9810
1374.769717 0.9790 0.9790 0.9790 0.9790 0.9780
1379.442629 0.9730 0.9660 0.9630 0.9620 0.9600
1384.115541 0.9620 0.9620 0.9630 0.9660 0.9690
1388.788453 0.9730 0.9790 0.9850 0.9890 0.9890
1393.461364 0.9910 0.9910 0.9920 0.9920 0.9940
1398.134276 0.9950 0.9950 0.9950 0.9950 0.9950
1402.807188 0.9950 0.9950 0.9950 0.9940 0.9950
1407.480100 0.9950 0.9950 0.9950 0.9950 0.9950
1412.153012 0.9950 0.9970 0.9970 0.9970 0.9980
1416.825923 0.9980 0.9970 0.9970 0.9950 0.9950
1421.498835 0.9950 0.9950 0.9950 0.9950 0.9950
1426.171747 0.9950 0.9950 0.9950 0.9950 0.9970
1430.844659 0.9970 0.9940 0.9940 0.9920 0.9920
1435.517571 0.9920 0.9910 0.9910 0.9920 0.9920
1440.190483 0.9920 0.9920 0.9920 0.9920 0.9920
1444.863394 0.9920 0.9920 0.9920 0.9920 0.9920
1449.536306 0.9920 0.9910 0.9910 0.9910 0.9890
1454.209218 0.9890 0.9880 0.9880 0.9880 0.9860
1458.882130 0.9860 0.9860 0.9880 0.9880 0.9890
1463.555042 0.9890 0.9890 0.9890 0.9890 0.9910
1468.227954 0.9910 0.9910 0.9910 0.9910 0.9910
1472.900865 0.9910 0.9910 0.9910 0.9910 0.9920
1477.573777 0.9910 0.9890 0.9890 0.9880 0.9860
1482.246689 0.9860 0.9860 0.9860 0.9860 0.9860
1486.919601 0.9860 0.9860 0.9880 0.9880 0.9890
1491.592513 0.9880 0.9880 0.9880 0.9880 0.9880
1496.265424 0.9880 0.9890 0.9890 0.9890 0.9880
1500.938336 0.9880 0.9880 0.9880 0.9880 0.9880
1505.611248 0.9880 0.9880 0.9890 0.9890 0.9890
1510.284160 0.9910 0.9890 0.9890 0.9890 0.9880
1514.957072 0.9880 0.9880 0.9880 0.9880 0.9880
1519.629984 0.9860 0.9860 0.9850 0.9860 0.9860
1524.302895 0.9860 0.9860 0.9860 0.9880 0.9880
1528.975807 0.9880 0.9880 0.9890 0.9890 0.9890
1533.648719 0.9890 0.9890 0.9880 0.9880 0.9880
1538.321631 0.9880 0.9860 0.9860 0.9860 0.9880
1542.994543 0.9860 0.9860 0.9860 0.9860 0.9880
1547.667454 0.9880 0.9880 0.9880 0.9890 0.9910
1552.340366 0.9910 0.9910 0.9910 0.9890 0.9880
1557.013278 0.9880 0.9880 0.9880 0.9880 0.9880
1561.686190 0.9880 0.9890 0.9880 0.9880 0.9880
1566.359102 0.9890 0.9890 0.9890 0.9890 0.9890
1571.032014 0.9880 0.9880 0.9880 0.9860 0.9860
1575.704925 0.9880 0.9860 0.9860 0.9860 0.9860
1580.377837 0.9860 0.9860 0.9860 0.9880 0.9880
1585.050749 0.9880 0.9890 0.9890 0.9910 0.9890
1589.723661 0.9890 0.9890 0.9890 0.9910 0.9890
1594.396573 0.9890 0.9890 0.9890 0.9890 0.9890
1599.069485 0.9890 0.9890 0.9890 0.9890 0.9880
1603.742396 0.9880 0.9890 0.9890 0.9890 0.9890
1608.415308 0.9890 0.9890 0.9890 0.9890 0.9880
1613.088220 0.9880 0.9880 0.9890 0.9890 0.9890
1617.761132 0.9890 0.9890 0.9890 0.9880 0.9860
1622.434044 0.9860 0.9880 0.9880 0.9890 0.9910
1627.106955 0.9910 0.9910 0.9910 0.9920 0.9910
1631.779867 0.9910 0.9910 0.9910 0.9920 0.9920
1636.452779 0.9940 0.9940 0.9940 0.9940 0.9950
1641.125691 0.9970 0.9970 0.9970 0.9980 0.9980
1645.798603 0.9980 0.9970 0.9970 0.9950 0.9950
1650.471515 0.9950 0.9940 0.9920 0.9920 0.9920
1655.144426 0.9920 0.9910 0.9890 0.9890 0.9890
1659.817338 0.9890 0.9890 0.9890 0.9890 0.9890
1664.490250 0.9890 0.9890 0.9890 0.9890 0.9880
1669.163162 0.9880 0.9880 0.9880 0.9880 0.9880
1673.836074 0.9880 0.9880 0.9890 0.9890 0.9880
1678.508985 0.9880 0.9860 0.9860 0.9910 0.9920
1683.181897 0.9920 0.9920 0.9920 0.9910 0.9910
1687.854809 0.9890 0.9890 0.9880 0.9860 0.9860
1692.527721 0.9860 0.9860 0.9860 0.9860 0.9860
1697.200633 0.9850 0.9850 0.9850 0.9850 0.9850
1701.873545 0.9850 0.9850 0.9850 0.9850 0.9850
1706.546456 0.9850 0.9850 0.9850 0.9860 0.9860
1711.219368 0.9880 0.9880 0.9860 0.9860 0.9860
1715.892280 0.9860 0.9860 0.9850 0.9850 0.9850
1720.565192 0.9850 0.9850 0.9840 0.9840 0.9840
1725.238104 0.9840 0.9840 0.9840 0.9840 0.9840
1729.911016 0.9840 0.9840 0.9840 0.9850 0.9850
1734.583927 0.9860 0.9860 0.9860 0.9860 0.9860
1739.256839 0.9860 0.9860 0.9850 0.9850 0.9850
1743.929751 0.9840 0.9850 0.9850 0.9850 0.9850
1748.602663 0.9850 0.9850 0.9850 0.9850 0.9850
1753.275575 0.9850 0.9850 0.9850 0.9850 0.9850
1757.948486 0.9850 0.9850 0.9850 0.9850 0.9850
1762.621398 0.9850 0.9850 0.9850 0.9850 0.9860
1767.294310 0.9860 0.9860 0.9860 0.9860 0.9860
1771.967222 0.9860 0.9860 0.9860 0.9860 0.9860
1776.640134 0.9860 0.9860 0.9860 0.9860 0.9860
1781.313046 0.9850 0.9860 0.9860 0.9860 0.9860
1785.985957 0.9860 0.9860 0.9860 0.9860 0.9860
1790.658869 0.9860 0.9860 0.9860 0.9860 0.9860
1795.331781 0.9860 0.9860 0.9860 0.9860 0.9860
1800.004693 0.9860 0.9860 0.9860 0.9860 0.9860
1804.677605 0.9860 0.9880 0.9880 0.9880 0.9880
1809.350516 0.9880 0.9880 0.9880 0.9880 0.9880
1814.023428 0.9880 0.9880 0.9880 0.9880 0.9880
1818.696340 0.9880 0.9880 0.9880 0.9880 0.9880
1823.369252 0.9880 0.9880 0.9880 0.9880 0.9880
1828.042164 0.9880 0.9880 0.9880 0.9880 0.9880
1832.715076 0.9880 0.9880 0.9880 0.9880 0.9880
1837.387987 0.9880 0.9880 0.9880 0.9880 0.9880
1842.060899 0.9880 0.9880 0.9880 0.9880 0.9880
1846.733811 0.9880 0.9880 0.9880 0.9880 0.9880
1851.406723 0.9880 0.9880 0.9880 0.9880 0.9880
1856.079635 0.9880 0.9880 0.9880 0.9880 0.9880
1860.752547 0.9880 0.9880 0.9880 0.9880 0.9880
1865.425458 0.9860 0.9860 0.9860 0.9860 0.9860
1870.098370 0.9860 0.9860 0.9860 0.9860 0.9860
1874.771282 0.9860 0.9860 0.9860 0.9860 0.9860
1879.444194 0.9860 0.9860 0.9860 0.9860 0.9860
1884.117106 0.9860 0.9860 0.9860 0.9860 0.9860
1888.790017 0.9860 0.9860 0.9860 0.9860 0.9860
1893.462929 0.9860 0.9860 0.9860 0.9860 0.9860
1898.135841 0.9860 0.9860 0.9860 0.9860 0.9860
1902.808753 0.9860 0.9860 0.9880 0.9880 0.9880
1907.481665 0.9860 0.9860 0.9860 0.9860 0.9860
1912.154577 0.9860 0.9860 0.9860 0.9860 0.9860
1916.827488 0.9860 0.9860 0.9860 0.9880 0.9880
1921.500400 0.9880 0.9880 0.9880 0.9880 0.9880
1926.173312 0.9880 0.9880 0.9880 0.9880 0.9880
1930.846224 0.9880 0.9880 0.9880 0.9880 0.9880
1935.519136 0.9880 0.9880 0.9860 0.9860 0.9860
1940.192047 0.9860 0.9860 0.9850 0.9840 0.9840
1944.864959 0.9840 0.9840 0.9840 0.9840 0.9850
1949.537871 0.9850 0.9850 0.9850 0.9850 0.9840
1954.210783 0.9820 0.9790 0.9780 0.9780 0.9790
1958.883695 0.9840 0.9860 0.9880 0.9880 0.9860
1963.556607 0.9880 0.9880 0.9890 0.9890 0.9890
1968.229518 0.9890 0.9890 0.9880 0.9890 0.9890
1972.902430 0.9890 0.9890 0.9890 0.9910 0.9910
1977.575342 0.9890 0.9890 0.9890 0.9890 0.9890
1982.248254 0.9890 0.9890 0.9890 0.9890 0.9890
1986.921166 0.9890 0.9890 0.9890 0.9890 0.9890
1991.594078 0.9890 0.9890 0.9890 0.9890 0.9890
1996.266989 0.9890 0.9890 0.9890 0.9890 0.9890
2000.939901 0.9890 0.9890 0.9890 0.9890 0.9890

Note that the absorbance of carbon dioxide contains multiple absorption lines (side bands) of diminishing strength around the main translational absorption wave number= 669 cm^-1. At higher carbon dioxide concentrations these sidebands play a major role in global warming. The main absorptin wavenumber 669 cm^-1 appears to be amplitude modulated by 9 cm^-1 and 51 cm^-1 signals, probably due to molecular rotation states.

The infrared absorption spectrum of carbon dioxide (CO2) recorded by the IRIS instrument in 1970 has a strong absorption band centered at 669 cm^-1 (15 um). The main absorption band clearly extends from 575 cm^-1 to 775 cm^-1 (17.39 um to 12.9 um). The IRIS instrument shows other smaller absorption bands on both sides of the main absorption band. The origin of these sidebands cannot be determined from the IRIS data alone. However, comparison of the IRIS data with the NIST data shows that the absorptions visible at 515 cm^-1, 548 cm^-1 and 800 cm^-1 on the IRIS data are all due to carbon dioxide.

At the central portion of the 15 um carbon dioxide absorption band only the temperature of the cold upper atmosphere is visible from outer space. At this wavelength the carbon dioxide in the lower atmosphere is opaque. Increasing the carbon dioxide concentration increases the absorption by side bands, making these sideband wavenumbers opaque as well. Thus, increasing the carbon dioxide concentration increases the apparent width of the main carbon dioxide absorption band, which decreases Ft and hence increases global warming. Note that the area of the main absorption band, if the carbon dioxide concentration is less than 16 times its present value, is bounded by 475 cm^-1, 875 cm^-1, the 215K black body line, the 290 K line and the water vapor absorption in the absence of carbon dioxide.

It is possible that carbon dioxide in the atmosphere combines with condensed water vapor droplets to form H2CO3, a wide band absorbing species. When there are no clouds there is no H2CO3, and hence this wide band absorption disappears. However, this wide band absorption may be negligible compared to water vapor absorption.Reference:Carbonic acid production in H2O:CO2 ices

As the concentration of carbon dioxide increases, Ftw(W) decreases at all the CO2 absorption lines (475 cm^-1 to 875 cm^-1) causing Ft to decrease. This decrease in Ft forces the temperature Ta to increase, and is the direct cause of global warming due to carbon dioxide.
 

OZONE:
A reference summarizing the absorption bands of ozone is:
Absorption band.

A reference summarizing ozone chemistry in the atmosphere is:
Stratospheric Ozone Chemistry

Recall that greenhouse warming is given by:
(Ta - Te) / Te = {[(1 - Fr) / Ft]^.25 - 1}
The effect of adding ozone (O3) to the atmosphere is to decrease Ft. Hence adding ozone has the effect of increasing greenhouse warming. However, ozone is kept in a constant equilibrium maintained by solar radiation. This equilibrium is in balance provided that there are no catalysts present such as chlorine atoms that destroy ozone. The total amount of ozone present is so small that only the main absorption band has any practical effect. The other absorption lines are too weak.

The main ozone absorption band of appears to have rounded edges. There is a rounded edge in the range 963 cm^-1 to 996 cm^-1. There strong absorptions at 1029 cm^-1 and 1056 cm^-1. There is another rounded edge in the range 1067 cm^-1 to 1080 cm^-1.

Ozone is catalyticly destroyed by chloro-fluorocarbon gases in the atmosphere. Due to the earth's magnetic field holes in the ozone layer tend to occur near the earth's magnetic poles. These holes allow more solar UV energy to reach the ground, contributing to melting of polar ice.

Ozone is not evenly distributed through the atmosphere. Ozone is concentrated in the upper atmosphere where it is made by interaction of UV light with oxygen. Since the total amount of ozone in the atmosphere is very small, its weak broad band absorption lines have little effect on Ft.

NIST INFRARED TRANSMITTANCE DATA FOR OZONE
Wavenumber(cm^-1)   Transmittance
402.089000 0.9630 0.9630 0.9630 0.9610 0.9590
408.616431 0.9590 0.9560 0.9560 0.9540 0.9540
415.143863 0.9520 0.9520 0.9480 0.9420 0.9400
421.671294 0.9380 0.9360 0.9340 0.9320 0.9320
428.198726 0.9300 0.9240 0.9220 0.9200 0.9200
434.726157 0.9150 0.9130 0.9130 0.9110 0.9090
441.253588 0.9050 0.9050 0.9050 0.9050 0.9050
447.781020 0.9030 0.9030 0.9010 0.9010 0.9010
454.308451 0.9010 0.9010 0.8990 0.8990 0.8970
460.835882 0.8950 0.8950 0.8950 0.8970 0.8970 460 weak absorption
467.363314 0.8990 0.8990 0.8990 0.8990 0.8990
473.890745 0.9010 0.9030 0.9030 0.9090 0.9090
480.418177 0.9090 0.9110 0.9110 0.9110 0.9110
486.945608 0.9130 0.9150 0.9180 0.9200 0.9200
493.473039 0.9200 0.9220 0.9220 0.9300 0.9340
500.000471 0.9340 0.9360 0.9360 0.9360 0.9360
506.527902 0.9380 0.9400 0.9420 0.9420 0.9440
513.055333 0.9440 0.9460 0.9460 0.9480 0.9500
519.582765 0.9520 0.9540 0.9560 0.9560 0.9590
526.110196 0.9590 0.9610 0.9630 0.9670 0.9710
532.637628 0.9730 0.9750 0.9770 0.9770 0.9790
539.165059 0.9830 0.9850 0.9870 0.9890 0.9910
545.692490 0.9930 1.0040 1.0060 1.0080 1.0080
552.219922 1.0100 1.0100 1.0120 1.0120 1.0160
558.747353 1.0180 1.0180 1.0180 1.0200 1.0220
565.274785 1.0220 1.0220 1.0240 1.0240 1.0240
571.802216 1.0260 1.0260 1.0260 1.0260 1.0260
578.329647 1.0260 1.0260 1.0280 1.0280 1.0280
584.857079 1.0260 1.0260 1.0260 1.0260 1.0260
591.384510 1.0260 1.0260 1.0260 1.0280 1.0280
597.911941 1.0280 1.0280 1.0280 1.0280 1.0260
604.439373 1.0260 1.0280 1.0280 1.0260 1.0260
610.966804 1.0240 1.0220 1.0220 1.0140 1.0080
617.494236 1.0060 1.0060 1.0060 1.0060 1.0060
624.021667 1.0040 1.0040 1.0020 1.0020 1.0000
630.549098 1.0000 1.0000 0.9970 0.9930 0.9890
637.076530 0.9810 0.9770 0.9750 0.9710 0.9670
643.603961 0.9610 0.9590 0.9481 0.9381 0.9320
650.131392 0.9300 0.9280 0.9240 0.9220 0.9200
656.658824 0.9200 0.9200 0.9200 0.9180 0.9180
663.186255 0.9130 0.9030 0.8950 0.8850 0.8790
669.713687 0.8750 0.8750 0.8830 0.8830 0.8174
676.241118 0.7950 0.7930 0.7930 0.7930 0.7930   676 absorption
682.768549 0.7930 0.7930 0.7930 0.7950 0.7970
689.295981 0.8050 0.8050 0.8110 0.8130 0.8150
695.823412 0.8230 0.8270 0.8360 0.8440 0.8460
702.350843 0.8500 0.8520 0.8520 0.8520 0.8520
708.878275 0.8520 0.8520 0.8520 0.8520 0.8520
715.405706 0.8500 0.8500 0.8500 0.8480 0.8460   715 Weak Absorption
721.933138 0.8480 0.8500 0.8540 0.8600 0.8660
728.460569 0.8700 0.8720 0.8750 0.8770 0.8790
734.988000 0.8830 0.8850 0.8850 0.8910 0.8910
741.515432 0.8930 0.8930 0.8950 0.8950 0.8950
748.042863 0.8990 0.9010 0.9050 0.9070 0.9110
754.570295 0.9110 0.9130 0.9130 0.9130 0.9130
761.097726 0.9150 0.9180 0.9180 0.9180 0.9180
767.625157 0.9180 0.9200 0.9200 0.9200 0.9200
774.152589 0.9180 0.9150 0.9150 0.9150 0.9130
780.680020 0.9070 0.9050 0.9030 0.9030 0.9010
787.207451 0.8990 0.8970 0.8950 0.8950 0.8910
793.734883 0.8890 0.8870 0.8870 0.8870 0.8890   793 Weak Absorption
800.262314 0.8890 0.8910 0.8910 0.8910 0.8910
806.789746 0.8910 0.8910 0.8930 0.8950 0.9010
813.317177 0.9050 0.9110 0.9110 0.9130 0.9150
819.844608 0.9180 0.9200 0.9220 0.9240 0.9240
826.372040 0.9240 0.9260 0.9260 0.9280 0.9280
832.899471 0.9280 0.9280 0.9280 0.9280 0.9280
839.426902 0.9280 0.9260 0.9260 0.9260 0.9260
845.954334 0.9260 0.9240 0.9240 0.9240 0.9240   846 Weak Absorption
852.481765 0.9240 0.9240 0.9260 0.9260 0.9260
859.009197 0.9260 0.9260 0.9260 0.9260 0.9260
865.536628 0.9260 0.9260 0.9260 0.9260 0.9260
872.064059 0.9260 0.9260 0.9260 0.9260 0.9260
878.591491 0.9260 0.9260 0.9260 0.9260 0.9260
885.118922 0.9260 0.9260 0.9260 0.9260 0.9260
891.646354 0.9260 0.9240 0.9240 0.9220 0.9220  892 Weak Absorption
898.173785 0.9220 0.9220 0.9240 0.9240 0.9220
904.701216 0.9200 0.9200 0.9200 0.9200 0.9200
911.228648 0.9200 0.9180 0.9180 0.9180 0.9180
917.756079 0.9180 0.9150 0.9150 0.9150 0.9150
924.283510 0.9150 0.9130 0.9130 0.9130 0.9130
930.810942 0.9110 0.9110 0.9110 0.9110 0.9090
937.338373 0.9090 0.9090 0.9070 0.9070 0.9070
943.865805 0.9070 0.9070 0.9070 0.9070 0.9070
950.393236 0.9070 0.9070 0.9070 0.9070 0.9070
956.920667 0.9050 0.9070 0.9070 0.9070 0.9050
963.448099 0.9050 0.9050 0.9050 0.9030 0.9030
969.975530 0.9010 0.9010 0.8990 0.8970 0.8950
976.502961 0.8950 0.8930 0.8910 0.8870 0.8830
983.030393 0.8790 0.8750 0.8700 0.8640 0.8580   
989.557824 0.8540 0.8360 0.8310 0.8170 0.7990   990 Low Frequency Edge
996.085256 0.7820 0.7661 0.7580 0.7291 0.7131        ABSORPTION
1002.612687 0.6940 0.6700 0.6330 0.6020 0.5880       ABSORPTION
1009.140118 0.5611 0.5361 0.4912 0.4562 0.4361       ABSORPTION
1015.667550 0.3990 0.3910 0.3810 0.3660 0.3480       ABSORPTION
1022.194981 0.3171 0.2931 0.2821 0.2721 0.2621       ABSORPTION
1028.722413 0.2600 0.2600 0.2600 0.2600 0.2620  1029 Local MAXIMUM ABSORPTION
1035.249844 0.2660 0.2720 0.2720 0.2740 0.2740       ABSORPTION
1041.777275 0.2739 0.2314 0.7170 0.5771 0.4362  1042 Local Minimum absorption
1048.304707 0.3911 0.3461 0.2683 0.2133 0.1633       ABSORPTION
1054.832138 0.1470 0.1390 0.1350 0.1370 0.1450  1054 MAXIMUM ABSORPTION
1061.359569 0.1550 0.1650 0.2596 0.4660 0.5018       ABSORPTION
1067.887001 0.5882 0.7251 0.7970 0.8340 0.8500  1068 High Frequency Edge
1074.414432 0.8520 0.8540 0.8540 0.8600 0.8680  
1080.941864 0.8700 0.8720 0.8720 0.8750 0.8770
1087.469295 0.8790 0.8810 0.8810 0.8830 0.8830
1093.996726 0.8830 0.8830 0.8830 0.8830 0.8830
1100.524158 0.8830 0.8850 0.8850 0.8850 0.8850
1107.051589 0.8850 0.8830 0.8830 0.8830 0.8830
1113.579020 0.8830 0.8830 0.8830 0.8810 0.8810  1114 Weak Absorption
1120.106452 0.8810 0.8810 0.8830 0.8830 0.8830
1126.633883 0.8830 0.8830 0.8850 0.8890 0.8890
1133.161315 0.8910 0.8910 0.8930 0.8930 0.8930  
1139.688746 0.8910 0.8910 0.8870 0.8870 0.8850  1140 Weak Absorption
1146.216177 0.8870 0.8910 0.8910 0.8930 0.8930
1152.743609 0.8930 0.8930 0.8930 0.8930 0.8950
1159.271040 0.8950 0.8950 0.8930 0.8910 0.8890  1159 Weak Absorption
1165.798471 0.8870 0.8890 0.8950 0.9089 0.9110
1172.325903 0.9110 0.9130 0.9150 0.9200 0.9200
1178.853334 0.9130 0.9090 0.9090 0.9110 0.9150  1179 Weak Absorption
1185.380766 0.9180 0.9220 0.9260 0.9300 0.9300
1191.908197 0.9300 0.9320 0.9320 0.9320 0.9320
1198.435628 0.9320 0.9320 0.9280 0.9200 0.8910
1204.963060 0.8750 0.8720 0.8700 0.8700 0.8700
1211.490491 0.8680 0.8680 0.8660 0.8620 0.8620
1218.017923 0.8580 0.8580 0.8620 0.8620 0.8640  1218 Weak Absorption
1224.545354 0.8640 0.8660 0.8700 0.8640 0.8640
1231.072785 0.8640 0.8640 0.8640 0.8660 0.8680
1237.600217 0.8700 0.8750 0.8770 0.8770 0.8770
1244.127648 0.8790 0.8790 0.8810 0.8810 0.8810
1250.655079 0.8810 0.8770 0.8750 0.8750 0.8720
1257.182511 0.8700 0.8700 0.8700 0.8700 0.8680
1263.709942 0.8680 0.8600 0.8600 0.8660 0.8660  1264 Weak Absorption
1270.237374 0.8660 0.8660 0.8660 0.8640 0.8640
1276.764805 0.8640 0.8620 0.8620 0.8640 0.8640
1283.292236 0.8680 0.8700 0.8700 0.8720 0.8720
1289.819668 0.8720 0.8700 0.8680 0.8680 0.8640
1296.347099 0.8600 0.8560 0.8520 0.8520 0.8520
1302.874530 0.8500 0.8500 0.8500 0.8480 0.8480  1303 Weak Absorption
1309.401962 0.8480 0.8480 0.8500 0.8500 0.8520
1315.929393 0.8520 0.8540 0.8560 0.8560 0.8560
1322.456825 0.8560 0.8560 0.8560 0.8560 0.8540
1328.984256 0.8540 0.8540 0.8520 0.8520 0.8520
1335.511687 0.8520 0.8500 0.8500 0.8480 0.8480
1342.039119 0.8480 0.8480 0.8460 0.8420 0.8380
1348.566550 0.8360 0.8360 0.8340 0.8310 0.8310
1355.093982 0.8290 0.8250 0.8230 0.8170 0.8130
1361.621413 0.8110 0.8110 0.8110 0.8110 0.8110
1368.148844 0.8090 0.8030 0.8010 0.7990 0.7970
1374.676276 0.7970 0.7970 0.7970 0.7970 0.7990  1375 Absorption
1381.203707 0.7990 0.7990 0.8010 0.8010 0.8050
1387.731138 0.8070 0.8090 0.8170 0.8170 0.8190
1394.258570 0.8190 0.8190 0.8210 0.8250 0.8270
1400.786001 0.8290 0.8310 0.8310 0.8340 0.8340
1407.313433 0.8360 0.8380 0.8400 0.8420 0.8420
1413.840864 0.8420 0.8420 0.8420 0.8311 0.8340  1414 Weak Absorption
1420.368295 0.8360 0.8420 0.8420 0.8440 0.8480
1426.895727 0.8480 0.8500 0.8500 0.8500 0.8500
1433.423158 0.8500 0.8500 0.8480 0.8380 0.8500  1434 Weak Absorption
1439.950589 0.8500 0.8500 0.8520 0.8520 0.8520
1446.478021 0.8520 0.8520 0.8500 0.8500 0.8500
1453.005452 0.8480 0.8440 0.8380 0.8360 0.8270   1453 Absorption
1459.532884 0.8340 0.8420 0.8440 0.8460 0.8460
1466.060315 0.8460 0.8460 0.8500 0.8500 0.8401
1472.587746 0.8340 0.8310 0.8340 0.8360 0.8440   1473 Absorption
1479.115178 0.8480 0.8480 0.8480 0.8500 0.8500
1485.642609 0.8500 0.8500 0.8420 0.8400 0.8360
1492.170040 0.8400 0.8420 0.8480 0.8500 0.8500
1498.697472 0.8460 0.8440 0.8440 0.8440 0.8440
1505.224903 0.8380 0.8250 0.8150 0.8150 0.8250   1505 Absorption
1511.752335 0.8270 0.8290 0.8340 0.8340 0.8310
1518.279766 0.8250 0.8190 0.8150 0.8170 0.8190   1518 Absorption
1524.807197 0.8210 0.8210 0.8210 0.8250 0.8270
1531.334629 0.8310 0.8310 0.8310 0.8310 0.8270
1537.862060 0.8190 0.8150 0.8110 0.8030 0.8030   1538 Absorption
1544.389492 0.8090 0.8130 0.8170 0.8230 0.8310
1550.916923 0.8360 0.8340 0.8310 0.8290 0.8290   1551 Weak Absorption
1557.444354 0.8110 0.7761 0.7760 0.8308 0.8340
1563.971786 0.8360 0.8360 0.8360 0.8290 0.8250   1564 Weak Absorption
1570.499217 0.8270 0.8360 0.8360 0.8360 0.8360
1577.026648 0.8250 0.8340 0.8360 0.8400 0.8420
1583.554080 0.8420 0.8420 0.8440 0.8440 0.8460
1590.081511 0.8460 0.8460 0.8440 0.8440 0.8440
1596.608943 0.8440 0.8440 0.8480 0.8480 0.8440
1603.136374 0.8440 0.8440 0.8440 0.8440 0.8440
1609.663805 0.8440 0.8420 0.8420 0.8420 0.8400
1616.191237 0.8290 0.8270 0.8290 0.8340 0.8340
1622.718668 0.8340 0.8340 0.8340 0.8340 0.8340
1629.246099 0.8310 0.8310 0.8340 0.8340 0.8340
1635.773531 0.8250 0.8150 0.8150 0.8270 0.8270
1642.300962 0.8270 0.8270 0.8250 0.8230 0.8210
1648.828394 0.8190 0.8170 0.8030 0.7861 0.7860   1649 Absorption
1655.355825 0.7951 0.8170 0.8230 0.8250 0.8290
1661.883256 0.8270 0.8250 0.8250 0.8250 0.8250
1668.410688 0.8170 0.8130 0.8110 0.8090 0.8090
1674.938119 0.8090 0.8110 0.8110 0.8130 0.8150
1681.465551 0.8130 0.8110 0.7970 0.7950 0.7950   1681 Absorption
1687.992982 0.8090 0.8110 0.8110 0.8090 0.8070
1694.520413 0.8050 0.8030 0.7970 0.7680 0.7640   1695 Absorption
1701.047845 0.7660 0.7969 0.7990 0.8010 0.7970
1707.575276 0.8010 0.8070 0.8090 0.8110 0.8110
1714.102707 0.8030 0.7950 0.7880 0.7721 0.7720   1714 Absorption
1720.630139 0.7820 0.7820 0.7840 0.7840 0.7840
1727.157570 0.7840 0.7840 0.7820 0.7780 0.7740
1733.685002 0.7580 0.7520 0.7450 0.7430 0.7430   1734 Absorption
1740.212433 0.7430 0.7430 0.7430 0.7450 0.7470
1746.739864 0.7500 0.7500 0.7520 0.7580 0.7600
1753.267296 0.7640 0.7700 0.7720 0.7760 0.7780
1759.794727 0.7820 0.7840 0.7840 0.7900 0.7930
1766.322158 0.7950 0.7970 0.7990 0.7990 0.7930
1772.849590 0.7900 0.7930 0.7950 0.7970 0.8030
1779.377021 0.8050 0.8090 0.8090 0.8090 0.8090
1785.904453 0.8090 0.8090 0.8090 0.8070 0.8070
1792.431884 0.8050 0.8050 0.8050 0.8070 0.8070   1792 Absorption
1798.959315 0.8070 0.8090 0.8090 0.8110 0.8110
1805.486747 0.8110 0.8130 0.8130 0.8130 0.8130
1812.014178 0.8150 0.8150 0.8170 0.8170 0.8190
1818.541610 0.8190 0.8210 0.8210 0.8210 0.8210
1825.069041 0.8190 0.8190 0.8170 0.8130 0.8130  1825 Absorption
1831.596472 0.8130 0.8150 0.8170 0.8190 0.8210
1838.123904 0.8210 0.8250 0.8250 0.8230 0.8130
1844.651335 0.8130 0.8150 0.8150 0.8190 0.8210   1845 Absorption
1851.178766 0.8230 0.8270 0.8270 0.8270 0.8290
1857.706198 0.8290 0.8290 0.8290 0.8290 0.8290
1864.233629 0.8290 0.8270 0.8270 0.8250 0.8250
1870.761061 0.8250 0.8270 0.8270 0.8270 0.8290   1871 Absorption
1877.288492 0.8290 0.8310 0.8310 0.8310 0.8310
1883.815923 0.8310 0.8310 0.8310 0.8340 0.8340
1890.343355 0.8310 0.8310 0.8310 0.8310 0.8310   1890 Absorption
1896.870786 0.8310 0.8310 0.8340 0.8340 0.8340
1903.398217 0.8340 0.8340 0.8340 0.8310 0.8310
1909.925649 0.8310 0.8310 0.8310 0.8290 0.8290
1916.453080 0.8270 0.8250 0.8250 0.8250 0.8270
1922.980512 0.8270 0.8270 0.8270 0.8250 0.8250   1923 Weak Absorption
1929.507943 0.8290 0.8290 0.8290 0.8290 0.8290
1936.035374 0.8290 0.8290 0.8290 0.8270 0.8270
1942.562806 0.8270 0.8270 0.8270 0.8270 0.8270
1949.090237 0.8270 0.8250 0.8250 0.8250 0.8250
1955.617668 0.8250 0.8250 0.8250 0.8230 0.8230   1956 Weak Absorption
1962.145100 0.8250 0.8250 0.8250 0.8250 0.8290
1968.672531 0.8290 0.8250 0.8250 0.8250 0.8270
1975.199963 0.8290 0.8290 0.8290 0.8270 0.8250
1981.727394 0.8250 0.8250 0.8250 0.8250 0.8270   1982 Weak Absorption
1988.254825 0.8270 0.8270 0.8250 0.8230 0.8230
1994.782257 0.8230 0.8250 0.8290 0.8290 0.8290
2001.309688 0.8290 0.8290 0.8280 0.8270 0.8220


Note the absorption band in the range 963 cm^-1 to 1080 cm^-1.There is a very narrow passband at 1041 cm^-1.

 

METHANE AND NITROUS OXIDE:
Methane (CH4) has an absorption band in the range 1200 cm^-1 to 1400 cm^-1 (8.3 um to 7.14 um). Nitrous oxide (N2O) has a narrow absorption line at 600 cm^-1 (16.6 um) and an absorption band in the range 1200 cm^-1 to 1350 cm^-1 (8.3 um to 7.4 um). The nitrous oxide absorption is coincident with the carbon dioxide and methane absorption bands, so when carbon dioxide and methane are both present the contribution of nitrous oxide is difficult to distinguish. Methane and nitrous oxide both have the potential to make a small contribution to greenhouse warming.
 

GLOSSARY OF TERMS

This web page last updated August 18, 2014

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