Observations of Gravity Wave Packets Using a Multiple Balloon, Multiple Linear Regression Technique

Abstract Typical climate model resolutions preclude the explicit simulation of most of the spectrum of atmospheric gravity waves (GWs). Climate models must therefore rely on GW parameterizations, which observations help constrain. Between 2011 and 2021, Loon LLC launched thousands of balloons, some of which flew close enough together to be affected by the same GW packet. These groups provide sufficient information to estimate the wavenumbers of GW packets. We identify 23 distinct GW packets seen by groups of four or more balloons using Wavelet analysis. For each GW packet, we perform a multiple linear regression using the balloons' spacing and phase offset to estimate the horizontal and vertical wavenumbers, which we use to calculate the phase speed and group velocity. Across the 23 packets found, we observe mostly low‐frequency GWs that propagate primarily meridionally. From packet properties and ERA5 reanalysis data, we test for proximity to convective and shear instabilities and find no preference for either. These results serve as a proof of concept for a novel GW property estimation technique.