Analyzing 2020 Total Solar Eclipse Generated Gravity Waves on Satellite Images

Major weather events (e.g., hurricane, volcano eruption) not only disturb the stable tropospheric atmosphere, but also trigger atmospheric gravity waves (AGWs) that carry momentum flux from the troposphere to the stratosphere and above. Upon detecting such gravity waves, recognizing the properties and origin of the waves can help understand AGW formation and propagation, and how they couple the lower and upper atmosphere and impact the climate. A total solar eclipse (TSE) happens once ~18 months, which causes a large area of sudden reduction of incoming solar radiation and thus excites AGWs. The excitation mechanism and source altitude remain in dark by far. This is one of the two science focus areas of the Nationwide Eclipse Ballooning Project (NEBP). Funded by NASA-Science Activation Program (SciACT), NEBP is an initiative to broaden participation from STEM learners with scientific ballooning by taking relay radiosonde measurements along the 2023 and 2024 solar eclipse tracks.

During the December 14, 2020 TSE event, the NEBP team carried a radiosonde campaign along the TSE path over Chile. In conjunction, AQUA-Atmospheric Infrared Sounder (AIRS) and NPP-Cross-track Infrared Sounder (CrIS) observations were collected during this event for cross-comparison for AGW characteristics in the stratosphere with the radiosonde observations. We applied the same signal processing procedures to the AIRS Level-1 radiance observations and CrIS Level-2 temperature retrievals, which are (1) high-pass filtering to extract small-scale perturbations; (2) Gabor filter to enhance the edge of AGW wave front and suppress high-frequency noises; (3) wavelet transform to extract AGW wavelength information. With these steps, two AGW packets along the TSE paths are identified from AIRS Level-1 data, but not from CrIS Level-2 retrievals. We speculate that the eclipse generated GWs are of small-scale and small amplitude, the signal of which is removed effectively from the retrieval process. We will show in this presentation the AGW characteristics from these two AGW packets and their comparisons to the radiosonde observed AGWs.