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Sodium lidar‐observed gravity wave breaking followed by an upward propagation of sporadic sodium layer over Hefei, China
Author(s) -
Ban Chao,
Li Tao,
Fang Xin,
Dou Xiankang,
Xiong Jiangang
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja021339
Subject(s) - lidar , gravity wave , meteor (satellite) , wind shear , geology , atmospheric sciences , sodium , gravitational wave , wind speed , meteorology , remote sensing , physics , materials science , astronomy , oceanography , metallurgy
The University of Science and Technology of China sodium temperature/wind lidar observed a strong zonal wind shear (~60 m/s/km) near 98 km between 1315 and 1330 UT on 29 July 2013 and a cooling near 96–100 km (above a warming near 90–95 km) between 1330 and 1430 UT. This suggests a possible gravity wave (GW) breaking event. Comparison of the lidar results with observations from a nearby meteor radar and with satellite results indicated that the GW likely broke down over a large horizontal area. In addition, the sodium number density suddenly increased 10–12 times (∼13, 000atm/cm 3 ) near 95 km at 1400 UT, immediately following the GW breaking. This sporadic sodium layer (SSL), which is different from most previously observed SSL events (which propagate downward), tended to propagate upward and also appeared ~2 min earlier in the west channel than in the east channel. The horizontal propagation direction of the SSL was aligned with the horizontal wind direction, which was likely due to the propagation of a high‐density sodium layer from the northwest of the lidar site, and was possibly related to the earlier GW breaking event.