Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring
Rapid restratification of the ocean surface boundary layer in the Indonesian-Australian Basin was captured in austral spring 2018, under the conditions of low wind speed and clear sky during the suppressed phase of Madden–Julian Oscillations (MJOs). Despite sunny days, strong diurnal variations of s...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2022-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ac4f11 |
| _version_ | 1827869538082881536 |
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| author | Je-Yuan Hsu Ming Feng Susan Wijffels |
| author_facet | Je-Yuan Hsu Ming Feng Susan Wijffels |
| author_sort | Je-Yuan Hsu |
| collection | DOAJ |
| description | Rapid restratification of the ocean surface boundary layer in the Indonesian-Australian Basin was captured in austral spring 2018, under the conditions of low wind speed and clear sky during the suppressed phase of Madden–Julian Oscillations (MJOs). Despite sunny days, strong diurnal variations of sea surface temperature (SST) were not observed until the wind speed became extremely low, because the decreasing wind speed modulated the latent heat flux. Combined with the horizontal advection of ocean current, the reduced upward heat loss inhibited the nighttime convective mixing and facilitated the restratification of the subsurface ocean layers. The surface mixed layer was thus shoaled up to 40 m in two days. The restratified upper ocean then sustained high SSTs by trapping heat near the sea surface until the onset of the MJO convection. This restratification process might be initialized under the atmospheric downwelling conditions during the suppressed phase of MJOs. The resulted high SSTs may affect the development and trajectories of MJOs, by enhancing air-sea heat and moisture fluxes as the winds pick up. Simulating this detailed interaction between the near-surface ocean and atmospheric features of MJOs remains a challenge, but with sufficient vertical resolution and realistic initial conditions, several features of the observations can be well captured. |
| first_indexed | 2024-03-12T15:45:38Z |
| format | Article |
| id | doaj.art-06001577888d40c08b2bf62cd9edb13e |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:45:38Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-06001577888d40c08b2bf62cd9edb13e2023-08-09T15:26:05ZengIOP PublishingEnvironmental Research Letters1748-93262022-01-0117202403110.1088/1748-9326/ac4f11Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral springJe-Yuan Hsu0https://orcid.org/0000-0002-4229-2633Ming Feng1Susan Wijffels2Institute of Oceanography, National Taiwan University , Taipei, TaiwanCSIRO Oceans and Atmosphere , Perth, Australia; Centre for Southern Hemisphere Oceans Research (CSHOR) , Hobart, AustraliaWoods Hole Oceanographic Institution , Woods Hole, United States of AmericaRapid restratification of the ocean surface boundary layer in the Indonesian-Australian Basin was captured in austral spring 2018, under the conditions of low wind speed and clear sky during the suppressed phase of Madden–Julian Oscillations (MJOs). Despite sunny days, strong diurnal variations of sea surface temperature (SST) were not observed until the wind speed became extremely low, because the decreasing wind speed modulated the latent heat flux. Combined with the horizontal advection of ocean current, the reduced upward heat loss inhibited the nighttime convective mixing and facilitated the restratification of the subsurface ocean layers. The surface mixed layer was thus shoaled up to 40 m in two days. The restratified upper ocean then sustained high SSTs by trapping heat near the sea surface until the onset of the MJO convection. This restratification process might be initialized under the atmospheric downwelling conditions during the suppressed phase of MJOs. The resulted high SSTs may affect the development and trajectories of MJOs, by enhancing air-sea heat and moisture fluxes as the winds pick up. Simulating this detailed interaction between the near-surface ocean and atmospheric features of MJOs remains a challenge, but with sufficient vertical resolution and realistic initial conditions, several features of the observations can be well captured.https://doi.org/10.1088/1748-9326/ac4f11importance of upper ocean stratified layers in air-sea interaction3D restratification processes near the sea surfacestrong diurnal variations of SSTMJO-ocean interaction during the suppressed phase of MJOsrapid restratification of the ocean surface boundary layer |
| spellingShingle | Je-Yuan Hsu Ming Feng Susan Wijffels Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring Environmental Research Letters importance of upper ocean stratified layers in air-sea interaction 3D restratification processes near the sea surface strong diurnal variations of SST MJO-ocean interaction during the suppressed phase of MJOs rapid restratification of the ocean surface boundary layer |
| title | Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring |
| title_full | Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring |
| title_fullStr | Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring |
| title_full_unstemmed | Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring |
| title_short | Rapid restratification of the ocean surface boundary layer during the suppressed phase of the MJO in austral spring |
| title_sort | rapid restratification of the ocean surface boundary layer during the suppressed phase of the mjo in austral spring |
| topic | importance of upper ocean stratified layers in air-sea interaction 3D restratification processes near the sea surface strong diurnal variations of SST MJO-ocean interaction during the suppressed phase of MJOs rapid restratification of the ocean surface boundary layer |
| url | https://doi.org/10.1088/1748-9326/ac4f11 |
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