(from ‘outer’ to ‘inner’:)
(the mesopause is the temperature minimum at the boundary between the ‘mesosphere’ and the ‘thermosphere’ atmospheric regions)
(due to the lack of ‘solar heating’ and very strong radiative cooling from carbon dioxide, the mesosphere is the coldest region on earth with temperatures as low as -100 °C (-148 °F or 173 K))
(the altitude of the mesopause for many years was assumed to be at around 85 km (53 mi.), but observations to higher altitudes and modeling studies in the last 10 years have shown that in fact the mesopause consists of 2 minima – one at about 85 km and a stronger minimum at about 100 km. (62 miles))
(another feature is that the ‘summer mesopause’ is cooler than the ‘winter’ (sometimes referred to as the ‘mesopause anomaly’)
(it is due to a ‘summer-to-winter’ circulation giving rise to ‘upwelling’ at the ‘summer pole’ and ‘downwelling’ at the ‘winter pole’)
(air rising will ‘expand’ and ‘cool’ resulting in a cold ‘summer mesopause’ and conversely downwelling air results in ‘compression’ and associated ‘increase in temperature’ at the ‘winter mesopause’)
(in the ‘mesosphere’ the ‘summer-to-winter circulation’ is due to ‘gravity wave dissipation’, which deposits momentum against the mean east-west flow, resulting in a small ‘north-south circulation’)
(in recent years the ‘mesopause’ has also been the focus of studies on ‘global climate change’ associated with increases in CO2)
(unlike the ‘troposphere’, where ‘greenhouse’ gases result in the atmosphere heating up, increased CO2 in the ‘mesosphere’ acts to cool the atmosphere due to increased ‘radiative emission’)
(this results in a measurable effect – the ‘mesopause’ should become cooler with increased CO2)
(observations do show a decrease of temperature of the ‘mesopause’, though the magnitude of this decrease varies and is subject to further study)
(modeling studies of this phenomenon have also been carried out)
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(***BACK TO “SUBDIVISIONS OF PLANET EARTH’S ATMOSPHERE”***)
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*TABLE OF CONTENTS*
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*”WE WON THE WAR”*
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