Upper atmospheric gravity wave details revealed in nightglow satellite imagery

Abstract

Gravity waves (disturbances to the density structure of the atmosphere whose restoring forces are gravity and buoyancy) comprise the principal form of energy exchange between the lower and upper atmosphere. Wave breaking drives the mean upper atmospheric circulation, determining boundary conditions to stratospheric processes, which in turn influence tropospheric weather and climate patterns on various spatial and temporal scales. Despite their recognized importance, very little is known about upper-level gravity wave characteristics. The knowledge gap is mainly due to lack of global, high-resolution observations from currently available satellite observing systems. Consequently, representations of wave-related processes in global models are crude, highly parameterized, and poorly constrained, limiting the description of various processes influenced by them. Here we highlight, through a series of examples, the unanticipated ability of the Day/Night Band (DNB) on the NOAA/NASA Suomi National Polar-orbiting Partnership environmental satellite to resolve gravity structures near the mesopause via nightglow emissions at unprecedented subkilometric detail. On moonless nights, the Day/Night Band observations provide all-weather viewing of waves as they modulate the nightglow layer located near the mesopause (∼90 km above mean sea level). These waves are launched by a variety of physical mechanisms, ranging from orography to convection, intensifying fronts, and even seismic and volcanic events. Cross-referencing the Day/Night Band imagery with conventional thermal infrared imagery also available helps to discern nightglow structures and in some cases to attribute their sources. The capability stands to advance our basic understanding of a critical yet poorly constrained driver of the atmospheric circulation.

Modeling Volcanic Eruption Parameters by Near-Source Internal Gravity Waves

“…Gravity waves have also been observed in satellite imagery725 as expanding pressure fronts centered around the volcano and consistent with the free oscillation of a fluid isothermal atmosphere triggered by the point injection of a large mass of volcanic material27. We have shown how the point source model272122 provides a reasonable and simple physical solution to explain the origin of atmospheric gravity oscillations at ~1 mHz also in near-source region79.…”

Dynamical Coupling Between Hurricane Matthew and the Middle to Upper Atmosphere via Gravity Waves

“…Also, its horizontal spatial resolution is uniform across the entire swath from nadir to both edges. This allows us to explore the subkilometer‐level details of GWs with vertical wavelengths longer than ~10 km (Miller et al, ), when the GWs modulate the airglow layer in the mesopause region.…”

“…GW propagation through or along the mesopause can produce fluctuations in the airglow brightness (Miller et al, ). Figures a and b show a VIIRS/DNB imagery collected at 06:51 UTC on 1 October.…”

“…Ground‐based airglow imagers in Japan observed typhoon excited GWs at the mesopause (Suzuki et al, ). From the top‐down perspective, two visible and near infrared (NIR) band sensors in space—(1) the Day/Night Band (DNB, Miller et al, ) of the Visible Infrared Imager Radiometer Suite (VIIRS) on board the Suomi National Polar‐orbiting Partnership (Suomi NPP) satellite and (2) the Visible‐light and Infrared Spectrum Imager of International Space Station Ionosphere, Mesosphere, Upper Atmosphere and Plasmasphere Mapping Mission—have observed a large number of TC GWs at the mesopause globally (Lai et al, ; Miller et al, ; Perwitasari et al, ; Yue et al, ). Both mesoscale (40‐ to 60‐km horizontal wavelength) and synoptic scale (~500‐km wavelength) GWs were observed over TC Mahasen (2013) in the Bay of Bengal (Yue et al, ).…”

New AIM/CIPS global observations of gravity waves near 50–55 km

“…Because the data from different instruments pertain to different spatial, spectral, and temporal scales [e.g., Alexander and Barnet, 2007], a complete understanding of GWs requires that the various observations be combined. Nadir sounders such as the Atmospheric Infrared Sounder (AIRS) [Gong et al, 2015;Hoffmann and Alexander, 2009] and the Visible Infrared Imaging Radiometer Suite (VIIRS) [Miller et al, 2015] have extensive horizontal coverage, but vertical weighting functions that limit vertical resolution and range. Nadir sounders such as the Atmospheric Infrared Sounder (AIRS) [Gong et al, 2015;Hoffmann and Alexander, 2009] and the Visible Infrared Imaging Radiometer Suite (VIIRS) [Miller et al, 2015] have extensive horizontal coverage, but vertical weighting functions that limit vertical resolution and range.…”