The gravity wave drag parametrization of the Whole Atmosphere Community Climate Model (WACCM) has been modified to include the wave-driven atmospheric vertical mixing caused by propagating, non-breaking, gravity waves. The strength of this atmospheric mixing is represented in the model via the "effective wave diffusivity" coefficient K_wave. Using K_wave, a new total dynamical diffusivity K_Dyn is defined. K_Dyn represents the vertical mixing of the atmosphere by both breaking (dissipating) and vertically propagating (non-dissipating) gravity waves. Here we show that, when the new diffusivity is used, the downward fluxes of Fe and Na between 80 and 100 km largely increase. Larger meteoric ablation injection rates of these metals (within a factor 2 of measurements) can now be used in WACCM, which produce Na and Fe layers in good agreement with lidar observations. Mesospheric CO2 is also significantly impacted, with the largest CO2 concentration increase occurring between 80-90 km, where model-observations agreement improves. However, in regions where the model overestimates CO2 concentration, the new parametrization exacerbates the model bias. The mesospheric cooling simulated by the new parametrization, while needed, is currently too strong almost everywhere. The summer mesopause in both hemispheres becomes too cold by about 30K compared to observations, but it shifts upward, partially correcting the WACCM low summer mesopause. Our results highlight the far-reaching implications and the necessity of representing vertically propagating gravity waves in climate models. This novel method of modelling gravity waves contributes to growing evidence that it is time to move away from dissipative-only gravity wave parametrizations.

SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) is a 10-channel infrared radiometer that is one of four instruments on the NASA TIMED (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics) satellite mission to study the structure, energetics, chemistry, and dynamics of the Earth’s mesosphere and lower thermosphere. The TIMED spacecraft was launched into a 625 km circular polar orbit (74.1º inclination) via a Boeing Delta II rocket from Vandenberg Air Force Base on 7 December 2001. SABER continues to operate nominally and collect data routinely as it has for over 21 years. Over 2,200 peer-reviewed journal articles have been published worldwide using SABER data. A list of these articles is included in the Supporting Information accompanying this paper. The Space Dynamics Laboratory (SDL) of Utah State University designed, fabricated, and calibrated the SABER instrument in close collaboration with NASA Langley Research Center, Hampton University, and Global Atmospheric Technologies and Science (GATS). This paper provides a detailed technical description of the SABER instrument, including performance specifications and observed instrument performance.

SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) is a 10-channel infrared radiometer that is one of four instruments on the NASA TIMED (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics) satellite mission to study the structure, energetics, chemistry, and dynamics of the Earth’s mesosphere and lower thermosphere. The TIMED spacecraft was launched into a 625 km circular polar orbit (74.1º inclination) via a Boeing Delta II rocket from Vandenberg Air Force Base on 7 December 2001. SABER continues to operate nominally and collect data routinely as it has for over 21 years. Over 2,200 peer-reviewed journal articles have been published worldwide using SABER data. A list of these articles is included in the Supporting Information accompanying this paper. This paper presents a detailed technical description of the SABER instrument including major subsystems of the instrument and technical performance parameters. This paper comprehensively describes the instrument and its components and provides final instrument design and performance parameters. The motivation for this paper is to document this information permanently for future reference. The Space Dynamics Laboratory (SDL) of Utah State University designed, fabricated, and calibrated the SABER instrument in close collaboration with NASA Langley Research Center, Hampton University, and Global Atmospheric Technologies and Science (GATS).

The ability of satellite instruments to accurately observe long-term changes in atmospheric temperature depends on many factors including the absolute accuracy of the measurement, the stability of the calibration of the instrument, the stability of the satellite orbit, and the stability of the numerical algorithm that produces the temperature data. We present an example of algorithm instability recently discovered in the temperature dataset from the SABER instrument on the NASA TIMED satellite. The instability resulted in derived temperatures that were substantially colder than anticipated from mid-December 2019 to mid-2022. This algorithm-induced change in temperature over one to two years corresponded to the expected change over several decades from increasing anthropogenic CO2. This paper highlights the importance of algorithm stability in developing Geospace Data Records (GDRs) for Earth’s mesosphere and lower thermosphere. A corrected version (Version 2.08) of the temperatures from SABER is described.

Elevated stratopauses are typically associated with prolonged disturbed conditions in the northern hemisphere polar winter. MIPAS and MLS observed a short-lived and highly zonally asymmetric stratopause at mesospheric altitudes in November 2009, the earliest in the season reported so far. The Arctic climatological winter stratopause vanished and MIPAS and MLS measured temperatures of 260K at 82\,km and 250K at 75\,km, respectively, in a region smaller than in typical mid-winter elevated stratopause events. Planetary wave activity was initially high. Zonal mean zonal winds and the poleward temperature gradient northward of 70$^\circ$N stayed reversed during 7 days. The mesosphere did not cool during that phase. Wave activity dropped until the eastward stratospheric zonal winds resumed, a strong vortex restored in the mesosphere, and the stratopause emerged at a high altitude. An enhanced downward transport followed. It took the stratopause 9 days to move down to its typical winter altitudes.