Evaluation of estimated mesospheric temperatures from 11-year meteor radar datasets of King Sejong Station (62°S, 59°W) and Esrange (68°N, 21°E)

Abstract

We have evaluated the reliability of two methods for estimating mesospheric temperatures from all-sky VHF meteor radar data. The first method utilizes the decay time of meteor trails, and the other method takes advantage of the linear relation between temperatures and the full width at half maximum (FWHM) of the observed meteor echoes height distribution. We estimated the temperatures from two meteor radar datasets of King Sejong Station (62.22°S, 58.78°W), Antarctic and Esrange, Sweden (67.90°N, 21.10°E) during a period of 2007–2017 and 2003 to 2013, respectively. We devised an improved decay time method of temperature estimation that utilizes careful selection of detected echoes by reflecting seasonal change in height range where ambipolar diffusion is dominant in meteor decay. Applying the improved method, we achieved temperature estimation on average within 6.2 and 5.4% from Aura/MLS temperatures around 90 km at Esrange and KSS, respectively. In comparison, temperatures estimated by the FWHM method have mean differences of 5.1 and 3.6% from the MLS temperatures at Esrange and KSS, respectively. The FWHM temperatures show significantly less discrepancy from MLS temperatures and temporal fluctuations than the temperatures estimated by the decay time for both sites. This may indicate that the FWHM method is more robust to estimate mesospheric temperatures from meteor radar data.