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Real-time SOI Data

Numerical data from here and values are calculated using the 1887-1989 base period. This information is usually updated every weekday at 2:00pm (AEST), public holidays excluded.

Date Pressure at Tahiti (hPa) Pressure at Darwin (hPa) Daily value 30-day average SOI 90-day average SOI
16-Oct-2019 1014.00 1011.50 -2.52 (+11.08) -7.95 (+0.11) -6.52 (+0.11)
15-Oct-2019 1012.88 1012.10 -13.60 (-7.86) -8.06 (-0.06) -6.63 (-0.03)
14-Oct-2019 1013.55 1011.55 -5.74 (-13.86) -8.00 (+0.70) -6.60 (+0.01)
13-Oct-2019 1014.55 1010.40 8.12 (+3.67) -8.70 (+1.23) -6.61 (+0.25)
12-Oct-2019 1014.13 1010.55 4.45 (+8.77) -9.93 (+0.97) -6.86 (+0.34)
11-Oct-2019 1013.52 1011.30 -4.32 (+7.03) -10.90 (+0.24) -7.20 (+0.18)
10-Oct-2019 1013.13 1012.00 -11.35 (-2) -11.14 (-0.01) -7.38 (+0.09)
9-Oct-2019 1013.19 1011.75 -9.35 (-7.41) -11.13 (+0.41) -7.47 (+0.12)
8-Oct-2019 1014.29 1011.70 -1.94 (+4.83) -11.54 (+0.63) -7.59 (+0.07)
7-Oct-2019 1014.24 1012.40 -6.77 (+4.45) -12.17 (+0.29) -7.66 (+0.11)
6-Oct-2019 1013.65 1012.50 -11.22 (+9.60) -12.46 (-0.03) -7.77 (+0.19)
5-Oct-2019 1012.66 1013.00 -20.82 (-1.03) -12.43 (-0.27) -7.96 (-0.07)
4-Oct-2019 1013.02 1013.20 -19.79 (+0.65) -12.16 (-0.17) -7.89 (-0.21)
3-Oct-2019 1013.57 1013.85 -20.44 (-8.51) -11.99 (-0.12) -7.68 (-0.18)
2-Oct-2019 1015.09 1014.05 -11.93 (-14.25) -11.87 (+0.29) -7.50 (-0.11)
1-Oct-2019 1017.10 1013.85 2.32 (-5.88) -12.16 (+0.56) -7.39 (+0.02)
30-Sep-2019 1017.40 1013.70 8.20 (+7.25) -12.72 (+0.67) -7.41 (+0.01)
29-Sep-2019 1016.68 1014.20 0.95 (+2.61) -13.39 (+0.72) -7.42 (+0.02)
28-Sep-2019 1016.39 1014.35 -1.66 (-3.68) -14.11 (+0.45) -7.44 (+0.09)
27-Sep-2019 1016.51 1013.85 2.02 (-0.36) -14.56 (+0.34) -7.53 (+0.31)
26-Sep-2019 1016.57 1013.85 2.38 (-3.62) -14.90 (+0.14) -7.84 (+0.33)
25-Sep-2019 1018.13 1014.80 6.00 (+8.43) -15.04 (+0.19) -8.17 (+0.40)
24-Sep-2019 1016.91 1015.00 -2.43 (+2.02) -15.23 (+0.10) -8.57 (+0.19)
23-Sep-2019 1016.52 1014.95 -4.45 (+7.49) -15.33 (+0.09) -8.76 (-0.01)
22-Sep-2019 1014.71 1014.40 -11.94 (+7.55) -15.42 (-0.54) -8.75 (-0.12)
21-Sep-2019 1012.89 1013.85 -19.49 (+8.26) -14.88 (-0.76) -8.63 (-0.01)
20-Sep-2019 1011.30 1013.65 -27.75 (+7.55) -14.12 (-0.56) -8.62 (+0.16)
19-Sep-2019 1010.93 1014.55 -35.30 (-14.33) -13.56 (-0.72) -8.78 (+/-0.00)
18-Sep-2019 1013.89 1015.10 -20.97 (-11.76) -12.84 (-1.06) -8.78 (-0.02)
17-Sep-2019 1015.32 1014.55 -9.21 -11.78 -8.76




Charts: 2019 | 2018 | 2017 | 2016 | 2015 | Source: The State of Queensland, Australia

ENSO Wrap Up (Source: here)

Issued on 15 October 2019

Positive Indian Ocean Dipole continues to strengthen

A strong positive Indian Ocean Dipole (IOD) continues to influence Australian and global climate. The El Niño–Southern Oscillation (ENSO) remains neutral.

The current positive Indian Ocean Dipole event has strengthened significantly over the past month. The latest weekly value of +2.15 °C is the strongest positive weekly value since at least 2001 (when the Bureau's weekly dataset commenced), and possibly since 1997, when strong monthly values were recorded. Over the past month, strong easterly trade winds across the tropical Indian Ocean aided upwelling of cooler water in the eastern Indian Ocean. At the same time, very warm waters off the Horn of Africa have caused an even greater temperature gradient across the basin.

Given the strength of the trade winds, the IOD may strengthen further over the next fortnight. However, international climate models surveyed by the Bureau indicate the positive IOD is unlikely to persist far into summer. IOD breakdown occurs when the monsoon trough moves into the southern hemisphere in early December. With the monsoon trough having a record-late retreat from India this year, the shift into the southern hemisphere may also be later than usual.

Typically, a positive IOD brings below average winter–spring rainfall to southern and central Australia, with warmer days for the southern two-thirds of the country. Positive IOD events are often associated with a more severe fire season for southeast Australia. Learn more about the Indian Ocean Dipole.

In the tropical Pacific Ocean, the El Niño–Southern Oscillation (ENSO) remains neutral. Most indicators of ENSO are near-average, although the Southern Oscillation Index (SOI) is negative (El Niño-like) due to very high atmospheric pressure at Darwin. The corresponding pressure in Tahiti is largely within normal bounds. This suggests the negative SOI is not related to a developing El Niño, but rather is likely related to the strong positive Indian Ocean Dipole and the cooler waters between Australia and Indonesia.

Climate models forecast neutral ENSO for the remainder of 2019 and into the first quarter of 2020. When ENSO is neutral, it has little effect on Australian and global climate, meaning other influences are more likely to dominate.


SOI summary:

The 30-day Southern Oscillation Index (SOI) for the 30 days ending 13 October was −8.5. The 90-day value was −7.2. Recent negative SOI values are due to very high atmospheric pressure over Darwin.

Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña. Values between +7 and −7 generally indicate neutral conditions.


Sea surface temperature summary:

Sea surface temperatures (SSTs) for the week ending 13 October remain warmer than average across the western to central equatorial Pacific Ocean, and slightly cooler than average in parts of the east, but overall patterns are consistent with a neutral ENSO state. Most of the northern half of the Pacific Ocean is warmer than average, as well as areas south of 30°S.

Cool anomalies remain in areas of the tropical Pacific east of 120°W, in parts of the South Pacific close to South America, and across waters between Australia and Papua New Guinea, the Arafura Sea, and on the southern side of the Indonesian archipelago. SSTs are more than 2 degrees cooler than average in some areas close to Sumatra. Cooler waters in the eastern Indian Ocean typically occur during a positive IOD. Warm anomalies have strengthened off the Horn of Africa, now reaching more than 2 degrees warmer than average. These strong warm anomalies off Africa, combined with very strong cool anomalies off the island of Sumatra reflect the current very strong positive values of the IOD index. (See weekly Indian Ocean SST anomaly map.)

The latest values of the three key NINO indices in the tropical Pacific for the week ending 13 October are: NINO3 +0.1 °C, NINO3.4 +0.5 °C and NINO4 +0.9 °C. All three NINO indices have warmed compared to two weeks ago.

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.


ENSO outlooks:

All eight surveyed international climate models indicate central tropical Pacific sea surface temperatures in the NINO3.4 region will remain at ENSO-neutral levels into early 2020.

One model indicates that values may move towards La Niña thresholds over summer, but does not reach the threshold until March. The remaining seven models are all maintain NINO3.4 values within the neutral range throughout the outlook period.

Last Accessed: Wed Oct 16 2019 23:07:47 HKT
Last Modified: Wed Jul 24 2019

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