Mesosphere

Mesosphere
Alexander Gerst · CC BY-SA 3.0 igo · source
Name	Mesosphere
Layer above	Thermosphere
Layer below	Stratosphere
Altitude range	50–85 km (approx.)
Main constituents	Nitrogen, O₂, Ozone
Temperature range	~200 K to 180 K (variable)
Notable features	Noctilucent clouds, Sporadic sodium layers, Meteor trails

Mesosphere The mesosphere is a layer of Earth's atmosphere situated between the Stratosphere and the Thermosphere, characterized by decreasing temperature with altitude, strong vertical mixing, and hosts unique optical and ionospheric phenomena. It interacts with phenomena studied by institutions such as NASA, European Space Agency, National Oceanic and Atmospheric Administration, JAXA, and Russian Academy of Sciences and is observed using platforms including sounding rockets, satellites, radar, and balloons.

Overview

The mesosphere occupies roughly 50–85 km above Earth's surface and is bounded by the Tropopause-adjacent regions defined in aeronomy research led by groups like American Meteorological Society and International Union of Geodesy and Geophysics. Studies by Gerald North, Carl Sagan, and teams at MIT and Harvard University have emphasized its role in coupling lower-atmosphere weather systems such as those tracked by European Centre for Medium-Range Weather Forecasts with upper-atmosphere processes investigated by NOAA and UK Met Office. Observational campaigns often coordinate across programs such as Campaign for Atmospheric and Mesospheric Studies and projects allied with Max Planck Institute for Solar System Research.

Structure and Properties

Vertically, the mesosphere is defined by gradients documented in work from Svante Arrhenius-inspired atmospheric physics and modern profiling by NASA missions and ESA instruments. Its density decreases exponentially as in canonical models developed at Jet Propulsion Laboratory and Smithsonian Institution. Turbulence, gravity waves, and planetary-scale waves identified in publications from American Geophysical Union and Royal Society shape its structure; studies referencing Ludwig Prandtl-influenced fluid dynamics and Fritz Haber-era photochemistry contribute to understanding diffusivity and eddy mixing. Mesospheric scale heights and pressure profiles are integrated into global circulation models at centers like NCAR and NOAA.

Temperature and Dynamics

Temperature in the mesosphere generally decreases with altitude to a cold trap, a phenomenon described in analyses by Vilhelm Bjerknes-inspired dynamics and refined by Jacob Bjerknes-era circulation studies. Thermodynamic balance involves radiative cooling by species investigated by Gordon Dobson's ozone measurements and dynamical heating from gravity waves studied at Scripps Institution of Oceanography and University of Colorado Boulder. Phenomena such as mesospheric inversion layers have been examined in papers from Caltech and University of Oxford and are modeled using frameworks from Richard Lindzen and Edward N. Lorenz for wave-mean flow interaction.

Composition and Chemistry

The mesosphere contains N₂, O₂, O, and trace O₃ and metal layers (e.g., Na, Fe, Ca) from meteoric ablation studied by Fred Whipple and teams at Cornell University. Photochemical reactions driven by ultraviolet flux measured by instruments on Landsat, TIMED, and Aqua influence odd-nitrogen and odd-oxygen cycles described in papers from University of Leeds and University of Manchester. Ionization processes producing sporadic layers are topics addressed by researchers at Dartmouth College and University of Tokyo.

Atmospheric Phenomena

The mesosphere hosts distinctive phenomena including Noctilucent clouds observed by SSTL and imaged by Olympus-era sensors, Noctilucent cloud variations tracked in studies by University of Colorado, University of Alaska Fairbanks, and University of Tromsø. Meteor ablation produces visible meteor trails and metal layers recorded by observatories such as Arecibo Observatory and arrays run by EISCAT. Polar mesospheric summer echoes, gravity waves, and planetary wave interactions are documented in literature from Lund Observatory, University of Oslo, and Stockholm University. Lightning-related sprites and elves connect mesospheric electrical activity with research at Princeton University and University of Minnesota.

Observation and Measurement

Measurements of mesospheric state variables come from sounding rockets launched by Wallops Flight Facility, lidar profilers operated by NCAR, microwave limb sounders aboard Aqua and Aura, and incoherent scatter radars such as EISCAT and Arecibo Observatory. Ground-based studies by University of Illinois and University of Colorado Boulder complement satellite remote sensing from missions like TIMED and instruments developed at JPL. International campaigns coordinated with World Meteorological Organization and COSPAR integrate datasets across facilities including Sondrestrom and Esrange.

Importance and Impact on Climate and Aviation

The mesosphere mediates coupling between tropospheric weather systems analyzed at European Centre for Medium-Range Weather Forecasts and thermospheric variability studied by NASA; impacts on trace gas distributions are relevant to assessments by Intergovernmental Panel on Climate Change authors and modeling centers like NCAR and Met Office Hadley Centre. While commercial aviation operated by carriers such as Boeing and Airbus rarely reaches mesospheric altitudes, high-altitude research aircraft and reentry vehicles developed by SpaceX, Blue Origin, Roscosmos, and European Space Agency must account for mesospheric drag and chemistry in mission planning. Changes in noctilucent cloud frequency and mesospheric temperatures are monitored in climate studies from University of Oxford and Princeton University to assess long-term atmospheric change.

Category:Atmospheric layers