Interannual variations of North Equatorial Current transport in the Pacific Ocean during two types of El Nino

• Published in: Chinese journal of oceanology and limnology Vol. 34; no. 3; pp. 585 - 596
• Main Author: 吴国丽 翟方国 胡敦欣
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.05.2016; Springer Nature B.V
• Subjects: Analysis; Annual variations; Anomalies; Earth and Environmental Science; Earth Sciences; Ekman pumping; El Nino; El Nino phenomena; Marine; Ocean circulation; Ocean currents; Oceanography; Pacific Ocean; Physics; Planetary waves; Pumping; Sea surface; Upwelling; Variation; Wave propagation; Weather forecasting; Wind; wind direction; Wind stress; Wind stress curl; 中期天气预报; 北赤道流; 厄尔尼诺; 年际变化; 热带太平洋; 热带西太平洋; 类型; 西风异常; Pacific Ocean; AS, Atlantic, North Equatorial Current; IS, Tropical Pacific; IN, North Pacific; El Niño; North Equatorial Current; transport; interannual variation
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-015-4352-y

Interannual variations of Pacific North Equatorial Current （NEC） transport during eastern- Pacific E1 Nifios （EP-EI Nifios） and central-Pacific E1 Nifios （CP-E1 Nifios） are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3. During EP-E1 Nifio, NEC transport shows significant positive anomalies from the developing to decay phases, with the largest anomalies around the mature phase. During CP-EI Nifio, however, the NEC transport only shows positive anomalies before the mature phase, with much weaker anomalies than those during EP-El Nifio. The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific. During EP-E1 Nifio, strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean, lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific. During CP-E1 Nifio, however, strength of the wind and associated Ekman pumping velocity are very weak. Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Nino.