Sara Taylor, Andrew F. Thompson, Luke Kachelein, Patrice Klein
Kinetic energy (KE) transfer between spatial scales contributes to the ocean's energy budget by linking scales of KE supply and KE dissipation. Numerical simulations have indicated that for scales smaller than the baroclinic deformation radius, cross-scale KE transfer has complex spatial and temporal variability, modulated by mixed layer properties, fronts, and eddies. Here, over a decade of upper-ocean surface velocity data, collected from high-frequency radar within the Santa Barbara Channel, are used to estimate cross-scale KE transfer. The transfer of KE across 7 km has strong seasonal and interannual variations linked to energy exchange with the atmosphere. This study observationally confirms (a) the importance of the surface divergence field in determining the direction of the KE transfer and (b) the equi-partitioning of KE transfer between divergent and straining motions. The temporal variability in KE transfer suggests that surface forcing influences the long-term redistribution of energy between scales.
{"title":"Seasonal to Interannual Cross-Scale Energy Transfer Variability: Observational Insight From the Santa Barbara Channel","authors":"Sara Taylor, Andrew F. Thompson, Luke Kachelein, Patrice Klein","doi":"10.1029/2025GL117885","DOIUrl":"https://doi.org/10.1029/2025GL117885","url":null,"abstract":"<p>Kinetic energy (KE) transfer between spatial scales contributes to the ocean's energy budget by linking scales of KE supply and KE dissipation. Numerical simulations have indicated that for scales smaller than the baroclinic deformation radius, cross-scale KE transfer has complex spatial and temporal variability, modulated by mixed layer properties, fronts, and eddies. Here, over a decade of upper-ocean surface velocity data, collected from high-frequency radar within the Santa Barbara Channel, are used to estimate cross-scale KE transfer. The transfer of KE across 7 km has strong seasonal and interannual variations linked to energy exchange with the atmosphere. This study observationally confirms (a) the importance of the surface divergence field in determining the direction of the KE transfer and (b) the equi-partitioning of KE transfer between divergent and straining motions. The temporal variability in KE transfer suggests that surface forcing influences the long-term redistribution of energy between scales.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"53 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL117885","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexandros C. Cooke-Politikos, Sergey Shuvalov, Yaxue Dong, Yi Qi, David A. Brain, Jasper S. Halekas
At Mars, the MAVEN spacecraft has made observations of Hot Flow Anomalies (HFAs) in the foreshock. Due to the bow shock's proximity to the planet, it is theorized that HFAs contribute to atmospheric escape at Mars through the excavation of ionospheric ions. A case study investigates one HFA observation, with parameters suggesting a novel mechanism for planetary ion extraction. The event is further characterized by elevated number densities of