First Simultaneous Lidar Observations of Thermosphere‐Ionosphere Sporadic Ni and Na (TISNi and TISNa) Layers (∼105–120 km) Over Beijing (40.42°N, 116.02°E)

Abstract

The meteoric metal layers in the Earth's upper atmosphere have received growing attention in recent years because of new observational discoveries made by high-sensitivity lidars and other remote sensing instruments (e.g., Chu et al.

Lidar Observations of Predawn Thermosphere‐Ionosphere Na (TINa) Layers Over Boulder (40.13°N, 105.24°W): Annual Phase Variations and Correlation With Sunrise and Tidal Winds

“…The production rate of TINa is k [Na + ][e − ] (Chu et al., 2020; Plane et al., 2015), where [Na + ] and [e − ] are Na + and electron densities. Rocket measurements show [Na + ] occupying the total electron density $$\left[{\text{Na}}^{+}\right]/\left[{\mathrm{e}}^{-}\right]=7.41\times {10}^{-2}/1.77=4.18\times {10}^{-2}$$ (Kopp, 1997; Wu et al., 2022). Assuming [e − ]∼5 × 10 4 cm −3 which is reasonable in converged ion layers, [Na + ] = 5 × 10 4 × 4.18 × 10 −2 = 2.1 × 10 3 cm −3 .…”

“…In the Na mixing ratio contours of qualified nights, predawn TINa layers are identified as layer structures that possess continuous phase evolutions of peak Na mixing ratios and whose maximum peak altitudes reach above 125 km. This threshold of 125 km is chosen to distinguish TINa layers from sporadic metal layers in the altitude range of 80–105 km (Plane, 2003) and from thermosphere‐ionosphere sporadic metal layers (Wu et al., 2022) that are usually below 120 km. Meteoric ablation efficiency decreases significantly above this altitude (Plane et al., 2015).…”

Seasonal Variation in the Mesospheric Ca Layer and Ca+ Layer Simultaneously Observed over Beijing (40.41°N, 116.01°E)

“…There are two distinct processes involved in the reaction of ionic compounds: dissociative recombination and the direct neutralization of metal ions through electron transfer. Wu et al [34] reported on the TISNi and TISNa layers seen in Beijing, spanning from 105 km to 120 km. Their findings indicate that TISNi and TISNa have similar formation mechanisms.…”

“…They mainly originate from the direct neutralization of Ni + and Na + with electrons [34]. To explore the formation of TISCa at 100 km to 115 km, this paper uses the ion-molecule reactions in Plane et al [3] and Plane et al [10] to deduce the first-order neutralization rates of Ca + [35][36][37] (see the Supplementary Materials), and the first-order neutralization rates of Na + , Ni + , and K + are derived from Jiao et al [35] and Wu et al [34]. Finally, the first-order neutralization rate curves for the dissociative recombination and direct recombination of metal Na + , Ni + , K + , and Ca + at f 0 Es = 10 MHz are plotted in Figure 7.…”

First Simultaneous Lidar Observations of Thermosphere-Ionosphere Sporadic Ni and Na (TISNi and TISNa) Layers (∼105–120 km) Over Beijing (40.42°N, 116.02°E)

“…Sporadic E data were provided by Beijing National Observatory of Space Environment, IGGCAS through the Geophysics Center, National Earth System Science Data Center (http://wdc.geophys.ac.cn). The data shown in this work, including the sporadic E data shown in Figure S1 in Supporting Information S1, can be downloaded in MatLab data format from Mendeley Data repository (Wu et al, 2022, https://doi.org/10.17632/scnxzsyj92.2).…”