3:30 PM - 4:50 PM
The Polar Research Institute of China has carried out observations of upper atmospheric physics with various instruments, such as, optical cameras, HF radar, imaging riometers, digisonde, magnetometers, TEC receiver, and so on, in both Antarctic and Arctic since it was founded in 1989. This talk will briefly introduce these observations at first and then present a statistical study on dayside diffuse aurora (DDA) based on ground optical observations obtained at Yellow River Station. We found that the DDAs can be commonly observed in the dayside and present different forms in the morning, noon, and afternoon. The DDAs observed near the magnetic local noon often show stripy structure and the orientation of stripy DDA is consistent with the ionospheric convection. Most interestingly, we found that the poleward end of the stripy DDA can extend to equatorward of the discrete auroral oval and is always connected with a discrete auroral arc that is north-south aligned and perpendicularly connected to the discrete aurora oval. The north-south aligned discrete auroral arc was named throat aurora and was suggested to be projection of newly opened flux of magnetopause reconnection. We argue that our observational results may present the optical evidence for the physical process of cold plasmas flowing into the dayside reconnection site and this process has very important implications.