Double séminaire LATMOS-Guyancourt, Salle 317, Vendredi 13 juin 2014, 11h

Orateurs: Prof. Xiankang DOU and Prof. Dongsong SUN (University of Science and Technology of China - USTC)

Dr. Prof. X. Dou, Vice president of the University of Science and Technology of China

Topics: ” Recent progress on sporadic sodium layers studies in MLT region detected by USTC/CMP lidars” (20min)

Abstract: The recent progress on sporadic sodium layers studies in MLT region using the USTC lidars and the lidars from the Chinese Meridian Project will be presented. Two cases of the lower thermospheric enhanced sodium layer (TeSL) was observed at a low latitude station, Lijiang, China (26N, 100E) on March 10, 2012 and April 10, 2012. In addition, strong sporadic sodium layers (SSLs) near 100 km accompanied the TeSL observed. Both the TeSLs and SSLs exhibited tidal-induced downward motion. The adjacent ground-based and space-borne ionospheric radio observations showed strong Es layers before the appearance of the TeSLs. I will also show the statistical features of sporadic sodium layers (SSLs) and the thermospheric enhanced layers (TeSLs) observed by a lidar chain located at Beijing (40N, 116E), Hefei (31.8N, 117.3E), Wuhan (30.5N, 114.4E), and Haikou (19.5N, 109.1E). Both the SSLs and TeSLs at four lidar sites showed evident summer enhancements and correlated well with Es. The co-observations of SSLs at three lidar site pairs indicated that a large-scale SSL extended horizontally for at least a few hundred kilometers and exhibited a tidal-induced modulation.

Dr. D. Sun, Profess, School of earth and space sciences, USTC

Topics: ”Lidar Development for Wind Measurement at USTC” (20min)

Abstract: The wind lidar system for upper atmosphere will be described. The Doppler frequency from the molecular backscattering is analyzed by a double Fabry-Perot etalon based technique. Some comparison field experiments between the lidar and the GPS radiosonde show good agreement. Continuous wind profiles in Delingha (37.4°N?97.4°E), China, demonstrated the stability and robustness of the lidar system.