Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments
Abstract Cusp-shaped fluctuations of the sea surface temperature (SST) front in the tropical Pacific, now known as tropical instability waves (TIWs), were discovered by remote sensing in the 1970s. Their discovery was followed by both theoretical and analytical studies, which, along with in situ obs...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
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Nature Portfolio
2023-09-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-023-41159-5 |
| _version_ | 1797453367882022912 |
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| author | Takahiro Toyoda L. Shogo Urakawa Hidenori Aiki Hideyuki Nakano Eiki Shindo Hiromasa Yoshimura Yuma Kawakami Kei Sakamoto Akio Yamagami Yusuke Ushijima Yayoi Harada Chiaki Kobayashi Hiroyuki Tomita Tomoki Tozuka Goro Yamanaka |
| author_facet | Takahiro Toyoda L. Shogo Urakawa Hidenori Aiki Hideyuki Nakano Eiki Shindo Hiromasa Yoshimura Yuma Kawakami Kei Sakamoto Akio Yamagami Yusuke Ushijima Yayoi Harada Chiaki Kobayashi Hiroyuki Tomita Tomoki Tozuka Goro Yamanaka |
| author_sort | Takahiro Toyoda |
| collection | DOAJ |
| description | Abstract Cusp-shaped fluctuations of the sea surface temperature (SST) front in the tropical Pacific, now known as tropical instability waves (TIWs), were discovered by remote sensing in the 1970s. Their discovery was followed by both theoretical and analytical studies, which, along with in situ observations, identified several possible generation mechanisms. Although modeling studies have shown that TIWs strongly influence the heat budget, their influence on local variations of realistically initialized predictions is not yet understood. We here evaluate a series of medium-range (up to ~ 10 days) coupled atmosphere–ocean predictions by a coupled model with different horizontal resolutions. Observational SST, surface wind stress, heat flux, and pressure data showed that representation of temporally and spatially local variations was improved by resolving fine-scale SST variations around the initialized coarse-scale SST front fluctuations of TIWs. Our study thus demonstrates the advantage of using high-resolution coupled models for medium-range predictions. In addition, analysis of TIW energetics showed two dominant sources of energy to anticyclonic eddies: barotropic instability between equatorial zonal currents and baroclinic instability due to intense density fronts. In turn, the eddy circulation strengthened both instabilities in the resolved simulations. This revealed feedback process refines our understanding of the generation mechanisms of TIWs. |
| first_indexed | 2024-03-09T15:20:51Z |
| format | Article |
| id | doaj.art-cfb2755c27d34bd78187733f43e9ecca |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-03-09T15:20:51Z |
| publishDate | 2023-09-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-cfb2755c27d34bd78187733f43e9ecca2023-11-26T12:48:55ZengNature PortfolioScientific Reports2045-23222023-09-0113111310.1038/s41598-023-41159-5Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experimentsTakahiro Toyoda0L. Shogo Urakawa1Hidenori Aiki2Hideyuki Nakano3Eiki Shindo4Hiromasa Yoshimura5Yuma Kawakami6Kei Sakamoto7Akio Yamagami8Yusuke Ushijima9Yayoi Harada10Chiaki Kobayashi11Hiroyuki Tomita12Tomoki Tozuka13Goro Yamanaka14Meteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyInstitute for Space–Earth Environmental Research, Nagoya UniversityMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyMeteorological Research Institute, Japan Meteorological AgencyFaculty of Environmental Earth Science and Graduate School of Environmental Science, Hokkaido UniversityDepartment of Earth and Planetary Science, Graduate School of Science, The University of TokyoMeteorological Research Institute, Japan Meteorological AgencyAbstract Cusp-shaped fluctuations of the sea surface temperature (SST) front in the tropical Pacific, now known as tropical instability waves (TIWs), were discovered by remote sensing in the 1970s. Their discovery was followed by both theoretical and analytical studies, which, along with in situ observations, identified several possible generation mechanisms. Although modeling studies have shown that TIWs strongly influence the heat budget, their influence on local variations of realistically initialized predictions is not yet understood. We here evaluate a series of medium-range (up to ~ 10 days) coupled atmosphere–ocean predictions by a coupled model with different horizontal resolutions. Observational SST, surface wind stress, heat flux, and pressure data showed that representation of temporally and spatially local variations was improved by resolving fine-scale SST variations around the initialized coarse-scale SST front fluctuations of TIWs. Our study thus demonstrates the advantage of using high-resolution coupled models for medium-range predictions. In addition, analysis of TIW energetics showed two dominant sources of energy to anticyclonic eddies: barotropic instability between equatorial zonal currents and baroclinic instability due to intense density fronts. In turn, the eddy circulation strengthened both instabilities in the resolved simulations. This revealed feedback process refines our understanding of the generation mechanisms of TIWs.https://doi.org/10.1038/s41598-023-41159-5 |
| spellingShingle | Takahiro Toyoda L. Shogo Urakawa Hidenori Aiki Hideyuki Nakano Eiki Shindo Hiromasa Yoshimura Yuma Kawakami Kei Sakamoto Akio Yamagami Yusuke Ushijima Yayoi Harada Chiaki Kobayashi Hiroyuki Tomita Tomoki Tozuka Goro Yamanaka Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments Scientific Reports |
| title | Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments |
| title_full | Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments |
| title_fullStr | Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments |
| title_full_unstemmed | Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments |
| title_short | Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere–ocean prediction experiments |
| title_sort | effective generation mechanisms of tropical instability waves as represented by high resolution coupled atmosphere ocean prediction experiments |
| url | https://doi.org/10.1038/s41598-023-41159-5 |
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