Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019
Abstract
:1. Introduction
2. Materials and Methods
3. Results
3.1. Climatological Distribution
3.2. Seasonal Variability
3.3. Interannual Variability
4. Discussion
4.1. Data Reanalysis
4.2. Integral Depth
4.3. EKE and the EAPE
5. Conclusions
- The 2D distribution images of the climatological mean EAPE show that the higher EAPE values are distributed in three regions, where two regions are located in the northern SCS, with one around 21° N to the west of the Luzon Strait and the other one around 17° N near Luzon Island. The third region is in the western SCS off the coast of Vietnam.
- The EAPE in the SCS presents an evident seasonal circle. The percentages of the seasonal EAPE over the total EAPE account for 21.6%, 23.2%, 24.2%, and 31.0% in spring, summer, autumn, and winter, respectively. A noticeable enhancement in winter is attributed to much weak stratification, especially in the northern SCS, which is favorable for enhancing the EAPE.
- In the northern SCS, the EAPE is generally smaller in spring and autumn and larger in summer and winter. The location of the peak EAPE has little seasonal variation around 21° N but moves westward to the central basin around 17° N. For the interannual variability, the EAPE in the two northern regions weakens during La Nina periods. ENSO plays an important role in the northern SCS.
- Off the Vietnam coast, the EAPE is closely related to coastal upwelling and presents higher values in autumn. The EAPE in this region has remarkable seasonal variabilities. During the La Niña events, the EAPE is enhanced and spreads from the Vietnam coast to the central SCS. During El Niño events, coastal upwelling and the EAPE are greatly suppressed. During the negative phase of the IOD, the EAPE is significantly enhanced in the western SCS, while there is no significant difference in the eastern SCS between the two IOD phases.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Season | Around 21 °N and West of Luzon Strait | Around 17 °N and West of Luzon Island | Off the Vietnam Coast | ||||||
---|---|---|---|---|---|---|---|---|---|
EAPE × 104 J m−2 | kg m−3 | log10 s−2 | EAPE × 104 J m−2 | kg m−3 | log10 s−2 | EAPE × 104 J m−2 | kg m−3 | log10 s−2 | |
Spring (March–May) | 1.33 | 0.22 | −3.71 | 1.01 | 0.25 | −3.59 | 0.84 | −0.03 | −3.60 |
Summer (June–August) | 1.33 | −0.21 | −3.62 | 1.26 | −0.44 | −3.57 | 0.98 | −0.20 | −3.57 |
Autumn (September–November) | 1.14 | −0.21 | −3.66 | 1.09 | −0.28 | −3.58 | 1.20 | 0.50 | −3.55 |
Winter (December–February) | 1.83 | 0.20 | −3.82 | 1.73 | 0.37 | −3.73 | 1.22 | 0.21 | −3.62 |
Mean | 1.41 | 0.21 1 | −3.70 | 1.27 | 0.33 1 | −3.62 | 1.06 | 0.23 1 | −3.59 |
STD | 0.30 | 0.01 | 0.09 | 0.32 | 0.09 | 0.08 | 0.18 | 0.20 | 0.03 |
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Li, Q.; Zhou, L.; Xie, L. Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019. Water 2021, 13, 926. https://doi.org/10.3390/w13070926
Li Q, Zhou L, Xie L. Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019. Water. 2021; 13(7):926. https://doi.org/10.3390/w13070926
Chicago/Turabian StyleLi, Qiang, Lei Zhou, and Lingling Xie. 2021. "Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019" Water 13, no. 7: 926. https://doi.org/10.3390/w13070926