Infrared Emission from the Stratosphere and Mesosphere

J. T. Houghton
1965 Proceedings of the Royal Society A  
T he co n trib u tio n s w hich stu d ies o f in frared em ission h av e m ad e to o u r know ledge o f th e stra to sp h e re a n d m esosphere are review ed. O bservations o f in frared em ission can be used to deduce com position a n d te m p e ra tu re in th e strato sp h e re . T he tra n sfe r of in frared ra d ia tio n is v e ry im p o rta n t in consid eratio n of th e energy b u d g e t o f th e stra to sp h e re a n d m eso sp h ere; n e a r th e m esopause, non-eq u ilib riu m
more » ... es m u st be included in energy b u d g e t studies. O bservations of th e in frare d airglow em ission from O H a n d 0 2 are briefly review ed. T he energy ra d ia te d b y O H n e a r 80 km is com p arab le w ith th a t ra d ia te d b y th e rm a l processes from o th e r in frared b ands. 1 . I n t r o d u c t i o n B ecause of th e presence in th e atm osphere of polyatom ic m olecules having strong ro ta tio n a n d v ib ra tio n -ro ta tio n absorption bands in th e infrared region, and because, a t atm ospheric tem p eratu res, th erm al processes can excite ro ta tio n a l and v ib ra tio n a l tran sitio n s, su b sta n tia l emission th ro u g h m uch of th e infrared region can be observed from th e atm osphere. T he ap p roxim ate d istrib u tio n of this em is sion w ith w avelength w hich w ould be received by a detector facing upw ards a t an b la c k b o d y \220°K w avelength (pm) F ig u r e 1. A pproxim ate spectral distribution of infrared emission from th e atm osphere above 15 km. a ltitu d e of 15 km , is shown in figure 1 . The m ain bands are due to th e molecules C0 2, H 20 a n d 0 3. O ther bands, too w eak to show on th e diagram , are due to m ethane a t 7-65 |xm an d nitrous oxide a t 7-78 jum. Only th e m ean outline of th e bands is draw n in figure 1 , such as would be observed by a spectrom eter of fairly low resolving power. I f an in stru m e n t of m uch higher resolving power were used, th e individual lines m aking up th e bands w ould be observed, having stru ctu re sim ilar to th a t shown in figure 2. [ 545 ]
doi:10.1098/rspa.1965.0241 fatcat:3qjrevsnj5d3rklbqq66i5nppy