Investigating Non-Propagating Waves in the Outflow Layer of Tropical Cyclones
Chamhitt, S., Nolan, D. S., Lawton, Q. A., Kukulies, J., Vömel, H.. (2025). Investigating Non-Propagating Waves in the Outflow Layer of Tropical Cyclones. , doi:https://doi.org/10.5065/a4nw-d771
| Title | Investigating Non-Propagating Waves in the Outflow Layer of Tropical Cyclones |
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| Genre | Manuscript |
| Author(s) | Shanna Chamhitt, D. S. Nolan, Quinton A. Lawton, Julia Kukulies, Holger Vömel |
| Abstract | Recent studies have investigated spiral gravity waves in tropical cyclones (TCs), where similar wave-like features have been observed in the upper outflow layer. Among these are non-propagating waves (NPWs), which are defined in this study as wave-like features that resemble gravity waves but lack their outward or spiral propagation. Despite being visually apparent in satellite imagery, NPWs remain largely unstudied, and their role in TC dynamics is unknown. This study explores whether NPWs can be quantitatively assessed using geostationary satellite data, under what conditions they are most likely to occur, and when they are most likely to occur. A set of major West Pacific tropical cyclones from 2014 to 2024 was manually inspected using visible satellite imagery. NPWs were observed in most storms, especially during periods of high intensity or times of intensification, and in environments with low vertical wind shear. To explore NPWs beyond visual identification, normalized radiance data were used to extract cross sections through the storm center and construct Hovmöller diagrams. Gravity waves appeared as outward-propagating diagonal features, while NPWs stood out as nearly vertically aligned, quasi-stationary structures. Although difficult to quantify directly, NPWs consistently appeared in both spatial and temporal fields, supporting their presence as coherent wave-like features. These results demonstrate that geostationary satellite data, particularly normalized radiance fields, can capture distinct differences between spiral gravity waves and NPWs in the TC outflow. This study serves as an initial step toward understanding NPWs and highlights the need for future efforts to objectively detect and assess them. |
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| Publication Date | Aug 1, 2025 |
| Publisher's Version of Record | https://doi.org/10.5065/a4nw-d771 |
| OpenSky Citable URL | https://n2t.net/ark:/85065/d7st7vb1 |
| OpenSky Listing | View on OpenSky |
| EOL Affiliations | ISF |