Estimation of Mesospheric Densities at Low Latitudes Using the Kunming Meteor Radar Together With SABER Temperatures

Abstract

Neutral mesospheric densities at a low latitude have been derived during April 2011 to December 2014 using data from the Kunming meteor radar in China (25.6°N, 103.8°E). The daily mean density at 90 km was estimated using the ambipolar diffusion coefficients from the meteor radar and temperatures from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument. The seasonal variations of the meteor radar‐derived density are consistent with the density from the Mass Spectrometer and Incoherent Scatter (MSIS) model, show a dominant annual variation, with a maximum during winter, and a minimum during summer. A simple linear model was used to separate the effects of atmospheric density and the meteor velocity on the meteor radar peak detection height. We find that a 1 km/s difference in the vertical meteor velocity yields a change of approximately 0.42 km in peak height. The strong correlation between the meteor radar density and the velocity‐corrected peak height indicates that the meteor radar density estimates accurately reflect changes in neutral atmospheric density and that meteor peak detection heights, when adjusted for meteoroid velocity, can serve as a convenient tool for measuring density variations around the mesopause. A comparison of the ambipolar diffusion coefficient and peak height observed simultaneously by two co‐located meteor radars indicates that the relative errors of the daily mean ambipolar diffusion coefficient and peak height should be less than 5% and 6%, respectively, and that the absolute error of the peak height is less than 0.2 km.

Long‐Term Distribution of Meteors in a Solar Cycle Period Observed by VHF Meteor Radars at Near‐Equatorial Latitudes

“…Therefore, a more in-depth discussion of these results is necessary. We found that the diurnal variation in meteor rates was affected by periodic solar radiation as given by Hajduk et al (1980), Lindblad (2003), and McIntosh and Hajduk (1977); the variation in meteor count rate reach their peaks once per year (Liu et al, 2017;Szasz et al, 2005;Yi et al, 2018;Younger et al, 2009; and the annual variation in meteor rates appears to have an inverse relationship with the 11-year solar cycle (Lindblad, 1967;Prikryl, 1983). This will be considered separately in this section.…”

“…Temporally and spatially, the trends of these two parameters are affected by the external energy of the MLT system, its internal dynamics, and coupling of the thermosphere and ionosphere (Qian & Solomon, 2012). To date, information on the meteor backscatter signal has allowed us to determine variations in atmospheric neutral density (Clemesha & Batista, 2006;Lima et al, 2015;Stober et al, 2014;Takahashi et al, 2002;Yi et al, 2018) and atmospheric neutral temperature in the region of meteoroid ablation (Hocking et al, 1997;Holdsworth et al, 2006;Kozlovsky et al, 2016;Yi et al, 2018). However, neutral atmospheric conditions in the MLT region are generally determined via empirical models.…”

“…The role of solar activity in meteor height and meteor rate has been reported and discussed. Several researchers (Hajduk et al, 1980;Lindblad, 1967Lindblad, , 2003Liu et al, 2017;McIntosh & Hajduk, 1977;Prikryl, 1983;Simek & Pecina, 2000;Szasz et al, 2005;Yi et al, 2018;Younger et al, 2009;Zigo et al, 2009) have observed variation in the intensity of meteor echoes and meteor rates due to the influence of solar activity. Additionally, other researchers have been used from radar at low latitude on southern hemisphere (Lima et al, 2015) and on northern hemisphere (Jacobi, 2014;Pecina & Simek, 1999;Pellinen-Wannberg et al, 2009;Porubčan & Cevolani, 1983) to investigate the effects of solar activity, described by solar radio flux, F10.7, and the number of solar sunspot (R), on meteor height distribution.…”

Climatology of the mesopause relative density using a global distribution of meteor radars

“…Here, to estimate the relative errors in D a and the density, we conduct a similar approach using simultaneous meteor echoes observed by two co-located meteor radars with different frequencies (33 and 55 MHz) at Davis Station. The 33 and 55 MHz meteor radars at Davis Station are described in related studies (see, e.g., Reid et al, 2006;Younger et al, 2014). Figure 2a shows the height distributions of meteor detections in 1 km bins on 1 January and 1 July 2006 for the 33 and 55 MHz meteor radars at Davis Station.…”

“…Geographic coordinates Frequency Data used in this study 2008) and geopotential height data (version 4) were restricted to data obtained within a 10 • × 20 • bounding box centered on each of the abovementioned meteor radar locations. Geometric heights, z, for Aura MLS observations were computed from geopotential heights, z g , via the equation (Younger et al, 2014), where R E (φ) is the radius of Earth at latitude φ, based on the WGS84 ellipsoid (Decker, 1986). The daily averaged MLS temperature and geometric height observations were interpolated into 1 km bins between 85 and 95 km to produce temperature profiles.…”