Rayleigh lidar observations of mesospheric inversion layers at Poker Flat, Alaska (65 °N, 147°W)

Abstract

Abstract. Rayleigh lidar measurements of the stratosphere and mesosphere have been made on an ongoing basis over a threeyear period at Poker Flat, Alaska (65 ø N, 147 ø W). These observations have yielded 27 nightly measurements of the middle atmosphere temperature profile (-40-80 km). These nighttime measurements are distributed between August and April. Mesospheric inversion layers have been observed on five occasions. The average altitude of the inversion layer peak is 60 km, with average amplitude of 1õ K. The temperature gradients on the topside of the inversion layers approach the adiabatic lapse rate. The inversion layers do not exhibit the apparent downward phase velocities that are commonly observed at lower latitudes. Furthermore, the inversion layers appear significantly less frequently than at lower latitudes. The observations are discussed in terms of current models and observations at other sites.

Simultaneous observations of a Mesospheric Inversion Layer and turbulence during the ECOMA-2010 rocket campaign

“…Both these scenarios are discussed in detail e.g., in the review article by Meriwether and Gerrard (2004). The adiabatic temperature gradient above both inversion layers detected in our case has been repeatedly observed by lidars (e.g., Whiteway et al, 1995;Thomas et al, 1996;Cutler et al, 2001;Duck and Greene, 2004;Liu et al, 2004;Collins et al, 2011) and has most often been the only argument regarding turbulence activity associated with temperature inversions. However, Thomas et al (1996) performed simultaneous observations of MILs with Rayleigh lidar and mesospheric echoes with VHF radar and concluded that both dynamic and convective instabilities (and, therefore, the generated turbulence) are associated with these phenomena.…”

Statistical characteristics of PMWE observations by the EISCAT VHF radar

“…They pointed out that broad spectra measured with the Indian MST Radar located in Gadanki are associated with so-called lower MILs observed by the co-located Rayleigh lidar and that both are related to strong turbulence activity at those heights. Lidar observations at mid-latitudes by Whiteway et al (1995); Thomas et al (1996); Liu et al (2004) and high-latitudes by Cutler et al (2001); Duck and Greene (2004); Collins et al (2011) have shown that MILs are often associated with turbulence activity which is reflected in the lidar temperature measurements as an adiabatic lapse rate on top of the inversion layers. On the other hand, numerical simulations by Liu et al (2000) showed that vigorous turbulence is required to change the thermal structure to the shape associated with temperature inversions.…”

Statistical analysis of the mesospheric inversion layers over two symmetrical tropical sites: Réunion (20.8° S, 55.5° E) and Mauna Loa (19.5° N, 155.6° W)

“…It is worth noting that this procedure has been applied in many previous studies investigating the phenomenon of mesospheric inversion (Leblanc et al, 1998;Meriwether and Gardner, 2000;Duck et al, 2001;Duck and Greene, 2004;Cutler et al, 2001;Siva Kumar et al, 2001;Ratnam et al, 2003;Gan et al, 2012). Figure 1 shows an example of a vertical temperature profile obtained from lidar and SABER observations over the Réunion site and showing a significant MIL structure.…”