Gaps identified in Antarctic gravitational wave simulations

The discovery of a defect can be the first ripple in a wave of innovation.

The Research Organization for Information and Systems (ROIS) and colleagues compared directly observed gravitational waves with the latest sophisticated simulations, revealing important limitations in current atmospheric modeling. Their findings highlight the complexity of these atmospheric waves and their impact on weather and climate systems.

The study was published in the September 2 issue of the Journal of the Meteorological Society of Japan.

Gravitational waves are similar to the ripples created when you throw a pebble into a still pond, but they travel through the air instead of water. Although mostly invisible, these waves play a huge role in shaping weather and climate, and are probably the main cause of the turbulence you’ve experienced on airplanes. Scientists and climate modelers are working harder than ever to characterize these atmospheric phenomena.

“Our aim was to characterize the gravitational waves we observed, assess how well they are represented in the latest reanalysis ERA5, and pinpoint where the model falls short.” said Yoshihiro Tomikawa, ROIS associate professor and lead author of the study.

ERA5 is a high-resolution atmospheric reanalysis of data obtained by assimilating observational data into simulations, and is widely used in climate research.

From January to February 2022, the team conducted simultaneous observations using a superpressure balloon and the large-scale atmospheric radar PANSY at Showa Station in Antarctica. They detected near-inertial frequency gravitational waves (NIGW) in the lower stratosphere. Although ERA5 was able to qualitatively capture these NIGWs, it underestimated their amplitude and could not represent one of the observed wave packets.

“Our study shows that even the high-resolution general circulation models used in the latest reanalysis cannot fully reproduce gravitational waves and their effects,” Tomikawa said.

This shortcoming can be attributed to the inability of ERA5 to simulate waves with very short vertical wavelengths and its limitations in tracking precise position.

This study highlights both the importance of direct observations and the challenges of accurately modeling small-scale atmospheric processes like gravitational waves. Addressing these simulation gaps is important to enhance weather forecasting and climate modeling.

Professor Tomikawa said, “We would like to continue simultaneous observations using superpressure balloons and the PANSY radar, and by combining observational data, models, and gravitational wave theory, we will elucidate the three-dimensional structure of the influence of gravitational waves on the Antarctic.” .