This is the Matlab routine used for the normal mode decomposition analysis in Giambenedetti et al., 2023 [1]. The code performs a normal mode decomposition on the assumption of Quasi-Geostrophic (Q-G) dynamics on the vertical profiles of buoyancy frequency (N^2), calculated directly from in-situ CTD data. This is an improved version of a code originally created by Rogério Chumbinho (Last modified October 1994) [2], given by Vincenzo Artale and Salvatore Marullo [3]. Modal shapes depend strongly on the amount of filtering applied to the profile. Best performances were obtained using a Savinsky-Golay filter of order 1 and frame length 15.
Dependencies:
- TEOS-10 functions http://www.teos-10.org/
Contents:
- example_data.txt example CTD data randomly generated
- NM_main.m main code to run
- NM_fun.m core function
- n_modes.m nested function
- filtering.m filters
- bruntvais.m N^2 calculation with the speed of sound correction
References: [1] Giambenedetti, B., Lo Bue, N., Kokoszka, F., Artale, V., and Falcini, F. (2023). Multiapproach analysis of baroclinic internal tide perturbation in the Ionian Sea abyssal layer (Mediterranean Sea). Geophysical Research Letters, 50, e2023GL104311. https://doi.org/10.1029/2023GL104311 [2] Chumbinho, R. P. A. (1994). Kinematics and dynamics of a cyclonic eddy off Pt. Arena, California (Doctoral dissertation, Monterey, California. Naval Postgraduate School). https://hdl.handle.net/10945/42791 [3] Artale, V., Falcini, F., Marullo, S., Bensi, M., Kokoszka, F., Iudicone, D., & Rubino, A. (2018). Linking mixing processes and climate variability to the heat content distribution of the Eastern Mediterranean abyss. Scientific reports, 8(1), 11317. https://doi.org/10.1038/s41598-018-29343-4