Studies of solar heating by CO2 in the upper atmosphere using a non-LTE model and satellite data

Solar heating and thermal cooling rates by the CO2 near-infrared bands in the mesosphere and lower thermosphere are derived from measurements of the CO2 4.3μm atmospheric emission by the Stratospheric and Mesospheric Sounder on Nimbus 7. A detailed analysis of the relaxation of the solar energy initially absorbed by the different bands, before it escapes to space or is thermalized, is included. The isotopic and hot bands of CO2 near 4.3μm play an important role since they produce a significant heating in the mesosphere and are important emitters of the solar energy absorbed at 4.3μm and 2.7μm around the mesopause. The pathways followed by the fraction of the electronic energy of O(1D) that is transferred into the CO2(0001)-N2(1) system have been studied, resulting that an important fraction of this energy is emitted by the CO2 4.3μm fundamental band in the lower thermosphere. -from Authors