- 1Forschungszentrum Juelich, ICE-4, Germany
- 2High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO, United States
- 3School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
- 4Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
CAIRT, the Middle-Atmosphere candidate and one of two finalists for ESA’s Earth Explorer
11 mission, offers unprecedented capabilities for observing and understanding atmospheric
dynamics. With an advanced infrared limb imager with high spectral resolution in the range of
720 cm-1 to 2200 cm-1, CAIRT is designed to measure a wide range of trace gas
concentrations and temperature from the upper troposphere and lower stratosphere (UTLS)
up to the lower thermosphere. The instrument enables 3D tomographic retrieval along the
satellite track with an along-track resolution of 50 km and an across-track resolution of 25 km
within a 400 km swath. In particular, temperature observations span altitudes of about 10 to
110 km with a 500 m vertical resolution, making CAIRT well-suited for observing Gravity Wave
(GW) activity throughout the middle atmosphere.
Here, we highlight CAIRT’s capabilities for GW observation and analysis based on model
simulations and synthetic retrieval runs. First, we present the methodology to isolate a
planetary wave (PW) background directly from the temperature observations, which is
essential for deriving the residual, GW-induced temperature perturbations.
Secondly, we demonstrate the analysis of the temperature residuals using the S3D
methodology (based on sinusoidal fits in limited volume data cubes). The analysis enables
robust estimation of individual GW parameters and allows the calculation of GW momentum
fluxes and the associated GW drag, thereby shedding light into the role of GWs in the middle
atmosphere dynamics. In particular, we investigate the GW contribution to the sudden
stratospheric warming (SSW) event during northern hemisphere winter 2018/2019.
Furthermore, the S3D methodology determines the 3D wave vector for individual GWs,
which we use for the initialization of GW ray-tracing to extend our analysis beyond the
observation window, offering insights into GW evolution and potential source regions.
If CAIRT is chosen as the Earth Explorer 11 following the User Consultation Meeting in July
2025, the mission would greatly increase our observational capabilities within the middle
atmosphere and advance our understanding of the middle atmosphere dynamics.
How to cite: Rhode, S., Ern, M., Preusse, P., Liu, H., Maniyattu, P., Mathew, A., Pedatella, N., Sinnhuber, B.-M., and Ungermann, J.: Gravity wave analyses with CAIRT – Temperature measurements, GWMF, and ray-tracing, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11207, https://doi.org/10.5194/egusphere-egu25-11207, 2025.
