YES THE MESOSPHERE IS WHERE ALL THOSE SMALL METEORS BURN UP AND THE MESOSPHERE GIVES US NOCTILUCENT CLOUDS, BUT THERE’S MORE TO THE MESOSPHERE IN THE AGE OF CLIMATE CHANGE. THIS POST IS A LITERATURE REVIEW ON THIS TOPIC.

RELATED POST ON NOCTILUCENT CLOUDS: LINK: https://tambonthongchai.com/2018/07/17/noctilucentclouds/

RELATED POST ON STRATOSPHERIC COOLING: LINK: https://tambonthongchai.com/2018/08/22/stratospheric-cooling/

RELATED 2016 PAPER ON THE VERTICAL PROFILE OF ATMOSPHERIC CO2 CONCENTRATION BY Johannes Klimpt, Elmar Friese, Hendrik Elbern: This idealized regional atmospheric inversion study assesses the potential of the 4-dimensional variational (4D-Var) method to estimate CO2 fluxes and the atmospheric CO2 concentration state jointly. In order to distinguish and quantify the surface-atmosphere CO2 fluxes, combining anthropogenic CO2 emissions, photosynthesis, and respiration: LINK: https://www.researchgate.net/publication/306338381

MESOSPHERE BIBLIOGRAPHY

Roble, R. G., and R. E. Dickinson. “How will changes in carbon dioxide and methane modify the mean structure of the mesosphere and thermosphere?.” Geophysical Research Letters 16.12 (1989): 1441-1444. A global average model of the coupled mesosphere, thermosphere and ionosphere is used to examine the effect of trace gas variations on the overall structure of these regions. In particular, the variations caused by CO₂ and CH₄ doublings and halvings from present day mixing ratios are presented. The results indicate that the mesosphre and thermosphere temperatures will cool by about 10K and 50K respectively as the CO₂ and CH₄ mixing ratios are doubled. These regions are heated by similar amounts when the trace gas mixing ratios are halved. Compositional redistributions also occur in association with changes in the temperature profile. The results show that global change will occur in the upper atmosphere and ionosphere as well as in the lower atmosphere during the 21st century

Thomas, G. E. “Is the polar mesosphere the miner’s canary of global change?.” Advances in Space Research 18.3 (1996): 149-158. The polar mesosphere is an atmospheric region located between latitude 50° and the pole, and between 50 and 90 km. During summer it becomes the coldest region on earth (<130K). This review focuses on past and future alterations of the temperature and water vapor content of this extremely cold region. These two influences are crucial for the formation of mesospheric ice particles in noctilucent clouds (NLC). A recent two-dimensional model study has been conducted of how long-term changes in carbon dioxide (CO₂) and methane (CH₄) concentrations may modify the temperature and water vapor concentration at mesopause heights. The model is a version of the well-known Garcia-Solomon model, modified to include accurate non-LTE cooling in the CO₂ 15 μm band. The existence region of NLC is defined as a domain where water-ice is supersaturated. Reduced levels of CO₂ and CH₄ are found to confine the model NLC existence region to within the perpetually-sunlit polar cap region, where the clouds would no longer be visible to a ground observer. A doubling of CO₂ and CH₄ could extend the NLC region to mid-latitudes, where they would be observable by a large fraction of the world’s population.

Schmidt, H., et al. “The HAMMONIA chemistry climate model: Sensitivity of the mesopause region to the 11-year solar cycle and CO2 doubling.” Journal of Climate 19.16 (2006): 3903-3931. This paper introduces the three-dimensional Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), which treats atmospheric dynamics, radiation, and chemistry interactively for the height range from the earth’s surface to the thermosphere (approximately 250 km). It is based on the latest version of the ECHAM atmospheric general circulation model of the Max Planck Institute for Meteorology in Hamburg, Germany, which is extended to include important radiative and dynamical processes of the upper atmosphere and is coupled to a chemistry module containing 48 compounds. The model is applied to study the effects of natural and anthropogenic climate forcing on the atmosphere, represented, on the one hand, by the 11-yr solar cycle and, on the other hand, by a doubling of the present-day concentration of carbon dioxide. The numerical experiments are analyzed with the focus on the effects on temperature and chemical composition in the mesopause region. Results include a temperature response to the solar cycle by 2 to 10 K in the mesopause region with the largest values occurring slightly above the summer mesopause. Ozone in the secondary maximum increases by up to 20% for solar maximum conditions. Changes in winds are in general small. In the case of a doubling of carbon dioxide the simulation indicates a cooling of the atmosphere everywhere above the tropopause but by the smallest values around the mesopause. It is shown that the temperature response up to the mesopause is strongly influenced by changes in dynamics. During Northern Hemisphere summer, dynamical processes alone would lead to an almost global warming of up to 3 K in the uppermost mesosphere.

Solomon, Stanley C., et al. “Whole atmosphere simulation of anthropogenic climate change.” Geophysical Research Letters 45.3 (2018): 1567-1576. We simulated anthropogenic global change through the entire atmosphere, including the thermosphere and ionosphere, using the Whole Atmosphere Community Climate Model‐eXtended. The basic result was that even as the lower atmosphere gradually warms, the upper atmosphere rapidly cools. The simulations employed constant low solar activity conditions, to remove the effects of variable solar and geomagnetic activity. Global mean annual mean temperature increased at a rate of +0.2 K/decade at the surface and +0.4 K/decade in the upper troposphere but decreased by about −1 K/decade in the stratosphere‐mesosphere and −2.8 K/decade in the thermosphere. Near the mesopause, temperature decreases were small compared to the interannual variation, so trends in that region are uncertain. Results were similar to previous modeling confined to specific atmospheric levels and compared favorably with available measurements. These simulations demonstrate the ability of a single comprehensive numerical model to characterize global change throughout the atmosphere. SUMMARY IN PLAIN LANGUAGE: We performed the first whole‐atmosphere simulations of global change that include the lower atmosphere (0–15 km), middle atmosphere (15–90 km), and thermosphere‐ionosphere (90–500 km). All significant known changes caused by human activity were included in a new version of the Whole Atmosphere Community Climate Model‐eXtended. The basic result is that even as the lower atmosphere gradually warms, the upper atmosphere rapidly cools. Simulations were conducted using constant low solar activity conditions, in order to remove the effects of the solar cycle on the upper atmosphere. Global mean annual average temperature increased at a rate of +0.2 K/decade at the surface and +0.4 K/decade about 10 km above the surface but decreased throughout the upper atmosphere, from about 20 km to 500 km, reaching −2.8 K/decade above 200 km. Near 90 km, very small temperature decreases were calculated, but the year‐to‐year variation was large, so temperature trends in that altitude region are uncertain. Results were similar to those obtained from previous work using numerical models that were confined to specific atmospheric levels and compare favorably with available measurements. These simulations demonstrate the ability of a single comprehensive numerical model to characterize global change throughout the atmosphere.

Qian, Liying, Christoph Jacobi, and Joseph McInerney. “Trends and solar irradiance effects in the mesosphere.” Journal of Geophysical Research: Space Physics 124.2 (2019): 1343-1360. We investigate trends and solar irradiance effects in the mesosphere using the Whole Atmosphere Community Climate Model with eXtended thermosphere and ionosphere (WACCM‐X) and radar measurements of winds at Collm (51°N, 13°E), for the period of 1980–2014. We found that in the mesosphere, dynamics significantly impact temperature and wind trends, as well as how solar irradiance affects the temperature and winds. The global average temperature trends are negative, with a maximum of ~−1 K per decade in the middle to lower mesosphere. Solar irradiance effects on the global average temperature are positive and decrease monotonically with decreasing altitude, changing from ~3 K/100 solar flux units (sfu) near the mesopause to ~1 K per 100 sfu in the lower mesosphere. In the summer upper mesosphere, temperature trends can become near 0 or positive, likely due to dynamical effects. Both wind trends and solar effects on the winds show dynamical patterns with negative and positive values, indicating that they are predominantly controlled by dynamics. The wind trends and solar effects on the winds are on the orders of ~±5 m/s per decade and ~±5 m/s per 100 sfu, respectively, and they are not as statistically significant as their temperature counterparts. At Collm (51°N, 13°E), the observed zonal winds at 90 km have a larger trend of 1.98 m/s per decade compared to the simulated zonal winds and it is statistically significant, but both the simulated and observed meridional winds do not have statistically significant trends.

SUMMARY AND CONCLUSION

Global warming by the greenhouse effect of atmospheric CO2 is a surface phenomenon limited to the lower 10km of the atmosphere. At higher altitudes we see mostly cooling or the absence of significant greenhouse effects. However, the upper atmosphere is more responsive to solar irradiance variation than the lower atmosphere. The failure of the critique of AGW theory with the solar irradiance argument may be understood in this context. LINKS TO RELATED POST ON SOLAR IRRADIANCE:

LINK#1: https://tambonthongchai.com/2020/06/16/a-grand-solar-minimum/ **

LINK#2: https://tambonthongchai.com/2019/02/26/a-chaotic-solar-cycle/ **

LINK#3: https://tambonthongchai.com/2019/07/23/cooling/