摘要
Winter coastal upwelling off northwest Borneo in the South China Sea （SCS） is investigated by using satellite data, climatological temperature and salinity fields and reanalysis data. The upwelling forms in Decem- ber, matures in January, starts to decay in February and almost disappears in March. Both Ekman trans- port induced by the alongshore winter monsoon and Ekman pumping due to orographic wind stress curl are favorable for the upwelling. Transport estimates demonstrate that the month-to-month variability of Ekman transport and Ekman pumping are both consistent with that of winter coastal upwelling, but Ek- man transport is two times larger than Ekman pumping in January and February. Under the influence of E1 Nino-Southern Oscillation （ENSO）, the upwelling shows remarkable interannual variability： during winter of El Nino （La Nina） years, an anticyclonic （a cyclonic） wind anomaly is established in the SCS, which behaves a northeasterly （southwesterly） anomaly and a positive （negative） wind stress curl anomaly off the north- west Borneo coast, enhancing （reducing） the upwelling and causing anomalous surface cooling （warming） and higher （lower） chlorophyll concentration. The sea surface temperature anomaly （SSTA） associated with ENSO off the northwest Borneo coast has an opposite phase to that off southeast Vietnam, resulting in a SSTA seesaw pattern in the southern SCS in winter.
Winter coastal upwelling off northwest Borneo in the South China Sea （SCS） is investigated by using satellite data, climatological temperature and salinity fields and reanalysis data. The upwelling forms in Decem- ber, matures in January, starts to decay in February and almost disappears in March. Both Ekman trans- port induced by the alongshore winter monsoon and Ekman pumping due to orographic wind stress curl are favorable for the upwelling. Transport estimates demonstrate that the month-to-month variability of Ekman transport and Ekman pumping are both consistent with that of winter coastal upwelling, but Ek- man transport is two times larger than Ekman pumping in January and February. Under the influence of E1 Nino-Southern Oscillation （ENSO）, the upwelling shows remarkable interannual variability： during winter of El Nino （La Nina） years, an anticyclonic （a cyclonic） wind anomaly is established in the SCS, which behaves a northeasterly （southwesterly） anomaly and a positive （negative） wind stress curl anomaly off the north- west Borneo coast, enhancing （reducing） the upwelling and causing anomalous surface cooling （warming） and higher （lower） chlorophyll concentration. The sea surface temperature anomaly （SSTA） associated with ENSO off the northwest Borneo coast has an opposite phase to that off southeast Vietnam, resulting in a SSTA seesaw pattern in the southern SCS in winter.
基金
The National Natural Science Foundation of China under contract No.91128212
the National Natural Science Foundation of China under contract No.41306024
the National Basic Research Program of China under contract No.2013CB430301
the National Science Fund of China for Distinguished Young Scholars(NSFDYS)under contract No.41125019
the Project of Global Change and Air-Sea Interaction under con-tract No.GASI-03-01-03-03
the Basic Research Program of Second Institute of Oceanography,State Oceanic Administration of China under contract No.JT1301
