Lidar observations of the upper atmospheric nickel layer at Beijing (40∘N,116∘E

A Comparison of the Midlatitude Nickel and Sodium Layers in the Mesosphere: Observations and Modeling

“…One dye laser excites the Na resonance fluorescence transition at 589 nm (Jiao et al., 2015). The second is frequency‐doubled to produce light at 341 nm with an average pulse energy of ∼30 mJ, which is used for Ni resonance fluorescence scattering (Wu et al., 2021). A 1200‐mm‐diameter Cassegrain telescope, coupled with the receiver unit (optical filters, photomultiplier tubes, and photon counters), detects Rayleigh scattering from air molecules and resonant fluorescence scattering from the Ni and Na layers.…”

“…The initial measurements of the Ni layer made by this lidar were analyzed by Wu et al. (2021): for 25 nights of measurements, the Ni peak density ranged from 98 to 460 cm −3 with the peak altitude between 80 and 88 km. In the present paper, this initial data set is substantially increased: from April 2019 to March 2020 and April 2021 to August 2021, we obtained 1090 hr of Ni and Na number density data, covering 126 nights of observations at Yanqing.…”

“…The average peak density of 258 ± 115 cm −3 and the Ni column abundance, which varied from (1.5–6.0) × 10 8 cm −2 between midsummer and midwinter, is in good agreement with the earlier Kühlungsborn result (Gerding et al., 2019). One standout feature that all three studies agree on is that the underside of the Ni layer profile is significantly broader than that of the Fe layer, often extending to below 80 km (Collins et al., 2015; Gerding et al., 2019; Wu et al., 2021).…”

“…Although the Ni layer was only observed for the first time in 2012 (Collins et al., 2015), much progress in understanding the characteristic features of the layer has been made in the past 5 years. This has been achieved through a combination of further observations (Gerding et al., 2019; Wu et al., 2021), laboratory studies of relevant physicochemical parameters (Bones et al., 2019, 2020; Daly et al., 2020; Mangan et al., 2019), and atmospheric modeling (Carrillo‐Sánchez et al., 2020; Daly et al., 2020).…”

“…The very large discrepancy between the results from Chatanika and Kühlungsborn stimulated a further Ni lidar study over 25 nights between April and December 2019 at Yanqing, China (40.41°N, 116.01°E) (Wu et al., 2021). This study reported that the Ni peak density ranged from 98 to 460 cm −3 with a peak altitude between 80 and 88 km.…”