The Atmospheric-Ionospheric-Magnetospheric Responses to the 2015 St. Patrick's Day Geomagnetic Storm at High Latitudes

The atmospheric-ionospheric-magnetospheric (AIM) system response to extreme solar wind conditions depends on the solar wind driving conditions, ionospheric configurations, and neutral atmospheric transportation. The 17 March 2015 geomagnetic storms driven by coronal mass ejections (CME) provide an opportunity to investigate how the global AIM response depends on the solar wind inputs. In this study, multiple instruments, including lidars, magnetometers, HF radars, satellites, and others, are combined to provide global, coordinated coverage in the AIM system. First, we examined the ionospheric responses at high latitude regions in both the northern and southern hemispheres, by using the conjugate West Greenland and Antarctic magnetometer chains to remotely sense several current systems. There were dramatic differences between the intensity, duration, and spatial structure of the current systems between hemispheres. Then, we examined the neutral atmospheric response and its connection with the MI systems in the high latitude regions with the Fe Boltzmann Lidar observations at the McMurdo station in Antarctica. The neutral Fe layer observed by Lidar from abnormally high altitudes (nearly 160km) is enhanced during the storm. It should be associated with not only the neutral atmospheric factors but also MI factors such as Joule heating and ionospheric electromagnetic drifting. These multiple instrument observations present an overall picture and help understand the AIM coupling mechanisms better.