Advanced mesospheric temperature mapper for high-latitude airglow studies

Abstract

Over the past 60 years, ground-based remote sensing measurements of the Earth's mesospheric temperature have been performed using the nighttime hydroxyl (OH) emission, which originates at an altitude of ∼87 km. Several types of instruments have been employed to date: spectrometers, Fabry-Perot or Michelson interferometers, scanning-radiometers, and more recently temperature mappers. Most of them measure the mesospheric temperature in a few sample directions and/or with a limited temporal resolution, restricting their research capabilities to the investigation of larger-scale perturbations such as inertial waves, tides, or planetary waves. The Advanced Mesospheric Temperature Mapper (AMTM) is a novel infrared digital imaging system that measures selected emission lines in the mesospheric OH (3,1) band (at ∼1.5 μm) to create intensity and temperature maps of the mesosphere around 87 km. The data are obtained with an unprecedented spatial (∼0.5 km) and temporal (typically 30″) resolution over a large 120° field of view, allowing detailed measurements of wave propagation and dissipation at the ∼87 km level, even in the presence of strong aurora or under full moon conditions. This paper describes the AMTM characteristics, compares measured temperatures with values obtained by a collocated Na lidar instrument, and presents several examples of temperature maps and nightly keogram representations to illustrate the excellent capabilities of this new instrument.

The Deep Propagating Gravity Wave Experiment (DEEPWAVE): An Airborne and Ground-Based Exploration of Gravity Wave Propagation and Effects from Their Sources throughout the Lower and Middle Atmosphere

“…Rayleigh and resonance lidars have likewise contributed to the definition of GW properties via measurements of temperatures, winds, and/or metallic species densities from very low altitudes to ~100 km or above (e.g., Chanin and Hauchecorne 1981;Gardner and Voelz 1987;She et al 1991;Whiteway and Carswell 1994;Williams et al 2006;Duck et al 2001;Alexander et al 2011;Lu et al 2015). Other optical instruments, especially ASIs and the newer AMTMs, provide valuable information on GW horizontal wavelengths, orientations, phase speeds, and amplitudes, sometimes at multiple altitudes, that contribute greatly to quantification of GW character, propagation, and potential for instability and mean flow interactions (e.g., Gavrilov and Shved 1982;Taylor et al 1995;Taylor and Hapgood 1988;Hecht et al 1997Hecht et al , 2001Walterscheid et al 1999;Nakamura et al 2003;Smith et al 2009;Pautet et al 2014;Hecht et al 2014;Fritts et al 2014).…”

A fast SWIR imager for observations of transient features in OH airglow

“…Hecht et al, 2002or Taguchi et al, 2004. Another type of instrument related to both spectrometers and imagers are the MTM (Mesospheric Temperature Mapper; Taylor et al, 1999) and the AMTM (Advanced Mesospheric Temperature Mapper; Pautet et al, 2014), both of which use very narrowband filters to isolate individual emission lines, allowing the determination of airglow temperature during later processing.…”

“…It is equipped with a three-stage thermoelectric cooler and usually cooled to 235 K to reduce the dark current. Similar detectors are used by Pautet et al (2014). The standard optics consist of an F# 1.4 Schneider-Kreuznach SWIRON lens with a focal length of 23 mm.…”

Simultaneous Observations of Mesoscale Gravity Waves Over the Central US with CRRL Na Doppler Lidars and USU Temperature Mapper

“…This study was enabled by the simultaneous observations with two Na Doppler lidars of the Consortium of Resonance and Rayleigh Lidars (CRRL) at Boulder, CO [4], and at Logan, UT [5], combining with an Advanced Mesospheric Temperature Mapper (AMTM) [6] The STAR lidar signal levels reached over 1000 counts/shot from 80 to 115 km with the averaged laser power of ~500 mW at 30 Hz repetition rate and a telescope primary mirror of ~80 cm in diameter. The raw lidar data were collected in the temporal and spatial resolutions of 3 s and 24 m. After binning to 5 min and 0.96 km, the measurement uncertainties in w and T are ~0.5 m/s and ~1 K near the Na layer peak.…”