59 research outputs found
Effect of planetary waves on cooling the upper mesosphere and lower thermosphere by the CO<sub>2</sub> 15-µm emission
Effect of planetary waves on cooling the upper mesosphere and lower thermosphere by the CO<sub>2</sub> 15-µm emission
International audienceThe steady-state 2-D linearized model of global-scale waves, calibrated according to available observations, is used to evaluate planetary-wave perturbations of temperature from the surface up to the height of about 165km. The maximum order of perturbation amplitudes in the upper mesosphere and lower thermosphere is found to be 15K for the ultra-fast Kelvin wave (UFKW) of the 3.5-day period, 8K for the 10-day wave, 5K for the 2- and 16-day waves, and 2K for the 5-day wave. The wave-caused variation in heat influx in the CO2 15-µm band, averaged over the wave period, depends on both the amplitude of temperature and temperature profile in the atmosphere unperturbed by the wave. An additional increase in radiative cooling is the prevailing effect of planetary waves in the upper mesosphere and lower thermosphere. The UFKW results in an increasing cooling rate up to ~0.1 of the cooling rate in the unperturbed atmosphere. The tangible contributions of the 2-, 10-, and 16-day waves are questionable. The contribution of the 5-day wave is negligible
Effect of planetary waves on cooling the upper mesosphere and lower thermosphere by the CO<sub>2</sub> 15-µm emission
The steady-state 2-D linearized model of global-scale waves,
calibrated according to available observations, is used to evaluate
planetary-wave perturbations of temperature from the surface up to the
height of about 165km. The maximum order of perturbation amplitudes in the
upper mesosphere and lower thermosphere is found to be 15K for the
ultra-fast Kelvin wave (UFKW) of the 3.5-day period, 8K for the 10-day
wave, 5K for the 2- and 16-day waves, and 2K for the 5-day wave. The
wave-caused variation in heat influx in the CO2 15-µm band,
averaged over the wave period, depends on both the amplitude of temperature and
temperature profile in the atmosphere unperturbed by the wave. An additional
increase in radiative cooling is the prevailing effect of planetary waves in
the upper mesosphere and lower thermosphere. The UFKW results in an increasing
cooling rate up to ~0.1 of the cooling rate in the unperturbed
atmosphere. The tangible contributions of the 2-, 10-, and 16-day waves are
questionable. The contribution of the 5-day wave is negligible
Effect of boundary conditions on the vibration frequencies and critical stresses of a cylindrical shell
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