Impact of molecular diffusion on the CO2 distribution and the temperature in the mesosphere -: art. no. 1729

被引:48
作者
Chabrillat, S
Kockarts, G
Fonteyn, D
Brasseur, G
机构
[1] Inst Aeron Spatiale, B-1180 Brussels, Belgium
[2] Max Planck Inst Meteorol, Hamburg, Germany
关键词
D O I
10.1029/2002GL015309
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Modelling the energy budget in the mesosphere and lower thermosphere requires a precise evaluation of CO2 distribution in this region. This distribution is primarily determined by competition between vertical eddy diffusion and molecular diffusion. A simple algorithm is proposed to take into account both processes, at all altitudes. Using the SOCRATES bi-dimensional model of the middle atmosphere, we show that molecular diffusion has a direct impact on CO2 vertical distribution down to approximately 80 km altitude, i.e. well into the mesosphere and below the turbopause altitude. A sensitivity study with regard to different aeronomical processes shows that molecular diffusion has the deepest influence in the mesospheric polar night region. Our model shows that molecular diffusion of CO2 is responsible for a polar night mesopause 12 K warmer than if this process was neglected. Hence, dynamical models should take this process in account across the whole mesospheric altitude range.
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页数:4
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