ECE Ph.D. student David Richardson won an Outstanding Student Presentation Award at the annual meeting of the American Geophysical Union (AGU) in New Orleans, LA, Dec. 13-17, 2021.

The selective award is given to fewer than 3% of all student presenters. AGU is the largest organization of Earth and space scientists in the world, and its annual meeting typically draws 25,000 presenters and attendees.

Richardson’s AGU presentation explored methods to unify two different, but complementary, approaches to mapping the electron density of the lower ionosphere (60-90 km altitude). This region impacts several critical forms of communications and responds to space weather (solar flares and storms) and being able to nowcast it would impact several different areas.

Much work has been done to use Very Low Frequency (VLF, 3-30 kHz) radio sources and receivers to do this, since VLF waves reflect efficiently from the lower ionosphere and are thus a remote sensing diagnostic. However, despite decades of research, this capability has not led to any operationally useful nowcasting of the lower ionosphere.

At this point there are two proposed methods to eventually do so. One involves using the natural VLF emissions from global lightning along with tomographic techniques to construct an image of the lower ionosphere. The other technique involves VLF communication beacons operated by the US Navy nominally for submarine communications, coupled with machine learning techniques to pull everything together.

Richardson’s work is the first real effort to merge the two methods together. This is a very difficult problem as the two sources of information - lightning emissions and communication beacons - couldn’t be more different from each other. The former is chaotic, with constantly shifting source locations characteristics of the emissions. The latter is steady and reliable but very limited in bandwidth and even more limited in where the sources are. Using data from Georgia Tech’s network of VLF receivers, he has been analyzing how the two algorithms could complement each other in a single unified approach. The eventual outcome could lead to improved communications for the aviation industry and others, and improved ability to detect and forecast space weather.

Richardson is a part of the Low Frequency Radio research group headed by ECE associate professor Morris Cohen. He worked in the Georgia Tech Research Institute (GTRI) before pursuing his Ph.D., and is a National Science Foundation (NSF) Graduate Research Fellow.