The near-global mesospheric potassium layer: Observations and modeling

Area of Science:

• Atmospheric chemistry and dynamics
• Upper atmosphere research
• Geophysics and space science

Background:

• Meteoric metal layers (K, Na, Fe) serve as tracers for atmospheric processes.
• Potassium (K) layers exhibit a distinct semiannual seasonality, contrasting with the annual cycles of Na and Fe.
• Previous K layer studies were limited to sparse ground-based lidar observations.

Purpose of the Study:

• To retrieve and analyze the near-global potassium (K) layer using satellite data for the first time.
• To validate a new potassium chemistry scheme within a whole atmosphere model.
• To investigate the global extent of K layer seasonality and its relationship with atmospheric phenomena.

Main Methods:

• Utilized spaceborne observations from the Optical Spectrograph and InfraRed Imager System (OSIRIS) on the Odin satellite (2004-2013).
• Employed a whole atmosphere chemistry climate model with a recently proposed potassium chemistry scheme.
• Validated model implementation against satellite-derived K layer data.

Main Results:

• Successfully retrieved the near-global K layer, confirming its semiannual seasonality with maxima in winter and summer.
• Demonstrated that this semiannual pattern is global, most pronounced at middle and high latitudes.
• Observed consistency between satellite and model data for K layer abundance, height, and width, aligning with lidar records.

Conclusions:

• The new potassium chemistry scheme provides a chemical basis for the observed semiannual K layer seasonality.
• Satellite data confirms the global nature of K layer semiannual variation.
• Further analysis explored the impact of polar mesospheric clouds and the occurrence of sporadic K layers.