Polar mesospheric cloud structures observed from the cloud imaging and particle size experiment on the Aeronomy of Ice in the Mesosphere spacecraft: Atmospheric gravity waves as drivers for longitudinal variability in polar mesospheric cloud occurrence

Abstract

[1] The cloud imaging and particle size (CIPS) experiment is one of three instruments on board the Aeronomy of Ice in the Mesosphere (AIM) spacecraft that was launched into a 600 km Sun-synchronous orbit on 25 April 2007. CIPS images have shown distinct wave patterns and structures in polar mesospheric clouds (PMCs), around the summertime mesopause region, which are qualitatively similar to structures seen in noctilucent clouds (NLCs) from ground-based photographs. The structures in PMC are generally considered to be manifestations of upward propagating atmospheric gravity waves (AGWs). Variability of AGW effects on PMC reported at several lidar sites has led to the notion of longitudinal differences in this relationship. This study compares the longitudinal variability in the CIPSobserved wave occurrence frequency with CIPS-measured PMC occurrence frequency and albedo along with mesospheric temperatures measured by the sounding of the atmosphere using broadband emission radiometry instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics spacecraft. Our results for the latitude ranges between 70°and 80°show a distinct anticorrelation of wave structures with cloud occurrence frequency and correlations with temperature perturbations for at least two of the four seasons analyzed, supporting the idea of gravity wave-induced cloud sublimation. The locations of the observed wave events show regions of high wave activity in both hemispheres. In the Northern Hemisphere, while the longitudinal variability in observed wave structures show changes from the 2007-2008 seasons, there exist regions of both low and high wave activities common to the two seasons. These persistent features may explain some of the observed differences in PMC activity reported by ground-based lidar instruments distributed at different longitudes. The statistical distribution of horizontal scales increases with wavelength up to at least 250 km. We also discuss the possibility of atmospheric tides, especially the nonmigrating semidiurnal tide, aliasing our observations and affecting the results presented in this analysis.

Wave influence on polar mesosphere summer echoes above Wasa: experimental and model studies

“…It is interesting to note that previously Chandran et al (2009) have obtained similar results, i.e. most of the waves had wavelengths less than 100 km, but later Chandran et al (2010) have argued that it was due to the visual detection method of wave patterns in CIPS images and ". .…”

“…Chandran et al (2010) have used images of polar mesospheric clouds made with the CIPS instrument onboard the AIM satellite and have found the distributions of horizontal wavelengths of gravity waves having a peak at 250-300 km; the study included both hemispheres between 70 and 80 • for the summer seasons of 2007 and 2008. Our estimation of horizontal wavelength equal to 252 km perfectly fits this result.…”

Global Dynamics of the MLT

“…Preusse et al (2009) calculated temperature variance from SABER data as an indictor of gravity wave activity. Another approach for determining gravity waves from satellite data was used by Surv Geophys (2012) 33:1177-1230 1189 Chandran et al (2010). They reported on the horizontal structure of gravity waves derived from satellite images of polar mesospheric clouds.…”

Characteristics and sources of gravity waves observed in noctilucent cloud over Norway

“…However, these observations are not possible during the high latitude polar summer when the mesosphere remains sunlit. Recently, Pautet et al (2011) recognized that even though it is not possible to use the airglow during this period, the structures present in the NLC, known to be caused by gravity waves and their instabilities (Hines, 1960;Thomas, 1991;Fritts et al, 1993;Chandran et al, 2009Chandran et al, , 2010, could themselves be used to infer the gravity waves present. Analyzing NLC images from Stockholm, Sweden (59.5 • N, 18.2 • E), they were able to provide the first climatology of gravity-wave wavelengths, phase speeds and propagation directions from 60 to 64 • N during the polar summer.…”