資料來源：請按此。此南方濤動指數是由1887至1989年的基數計算所得。資料每天 (公眾假期除外) 在澳洲東部標準時間下午2時更新一次。
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Issued on 19 June 2018
El Ni簽o WATCH; chance of El Ni簽o in spring increases to 50%
The El Niño–Southern Oscillation (ENSO) remains neutral. However, latest model outlooks and recent warming in the tropical Pacific Ocean indicates that the chance of El Niño forming in spring has increased. As a result, the Bureau's ENSO Outlook status has moved to El Niño WATCH. El Niño WATCH means that the likelihood of El Niño forming in 2018 is approximately 50%; double the normal chance.
Oceanic indicators are currently neutral—neither El Niño nor La Niña—but show some signs of potential El Niño development. Sea surface temperatures in the eastern Pacific Ocean, though currently neutral, have been slowly warming since April. Importantly, waters below the surface of the tropical Pacific are now warmer than average—a common precursor to El Niño.
The majority of international climate models surveyed by the Bureau forecast the tropical Pacific Ocean will continue to warm but stay in the neutral range during July and August. However, five of eight models indicate the ocean warmth is likely to reach El Niño thresholds in the southern hemisphere spring, while a sixth model falls just short.
During El Niño, rainfall in eastern Australian is typically below average during winter and spring. A neutral ENSO phase has little effect on Australian climate.
The Indian Ocean Dipole (IOD) remains neutral. Five of six climate models indicate the IOD is likely to remain neutral in the coming months, and one model suggests a positive IOD.
The 30-day Southern Oscillation Index (SOI) to 17 June was −2.2, and the 90-day SOI was +2.3. The SOI has been within the neutral range since late April.
Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below −7 typically indicate El Niño. Values between +7 and −7 generally indicate neutral conditions.
Sea surface temperatures (SSTs) across the central Pacific Ocean are slightly warmer than average along the eastern half of the equatorial Pacific.
The latest values for the week ending 17 June are: NINO3 +0.4 °C, NINO3.4 +0.3 °C and NINO4 +0.4 °C. Persistent NINO3 or NINO3.4 values warmer than +0.8 °C are typical of El Niño, while persistent values cooler than −0.8 °C typically indicate La Niña.
Warmer than average SSTs (more than 1 °C above average) persist in areas of the South Pacific Ocean and the Tasman Sea.
Around the north of Australia SSTs are generally near average. Further north, areas of weak warm anomalies remain in areas across the Maritime Continent to the north of Papua New Guinea.
All but one of the eight surveyed international climate models predict further warming of central equatorial Pacific sea surface temperatures (SSTs) over the coming months.
During the remainder of the southern hemisphere winter, all models forecast central Pacific SSTs to remain within neutral values. However, five of the eight models reach El Niño levels during spring, with a sixth model falling just short of the threshold value.
最近訪問日期: Tue Jun 19 2018 22:29:42 HKT
最近修訂日期: Mon Jul 11 2016