Climate Model Summary

Climate Model Summary Archive: February 2014

Models indicate tropical Pacific to warm

All of the international climate models surveyed by the Bureau of Meteorology indicate the El Niño-Southern Oscillation (ENSO) is likely to remain neutral into the austral autumn. However all models suggest warming of the tropical Pacific Ocean will occur leading into winter, with some (but not all) models either approaching or exceeding El Niño thresholds by July. Hence neither neutral nor El Niño states can be discounted for the second half of 2014, while La Niña appears unlikely.

It should be noted that model outlooks which span autumn tend to have lower skill than outlooks issued at other times of the year, therefore more or less warming than indicated remains possible. Key indicators of ENSO will continue to be monitored closely for any significant changes.

The Indian Ocean Dipole (IOD) is also neutral. The IOD typically has little impact upon Australian climate throughout the months from December to April.

NINO3.4 Outlook

The latest NINO3.4 forecasts (initialised in February) from all available models ENSO is likely to remain neutral throughout the austral autumn. All models surveyed indicate a warming trend leading into winter, with two of the seven models surveyed exceeding El Niño thresholds by July 2014. The Bureau will continue to monitor the ENSO state closely as forecasts enter the time of year when historically they have been more reliable. The most recent NINO3.4 value is –0.4 °C for the week ending 16 February 2014.

Indian Ocean Dipole (IOD)

The IOD index remains neutral with a latest weekly value of –0.4 °C for the week ending 16 February 2014. The IOD typically has little effect on Australian climate during the months from December to April. This is due to the IOD pattern being unable to form once the monsoon trough moves south over the eastern tropical Indian Ocean.

The following graph shows the average forecast value of the IOD index for each international model surveyed for the selected calendar month. If the majority of models are approaching or exceeding the blue dashed line, then there is an increased risk of a negative IOD event. If the majority of models are approaching or exceeding the red dashed line, then there is an increased risk of a positive IOD event.

Predictive Ocean Atmosphere Model for Australia (POAMA)

POAMA, run at the Bureau of Meteorology, generates an eight-monthly forecast on the first day of each month. The most recent model run (started in February) predicts NINO3.4 is most likely to remain within neutral values throughout the forecast period. The following forecast values are for the ensemble mean.

POAMA archive data is available here.

ENSO Dials

The arrows on the dials below indicate the combined average ofmonthly NINO3.4 outlooks from a survey of international global climate models. Note that the individual model runs vary around the average.

ENSO dial month+1 ENSO dial month+3 ENSO dial month+5

NINO3.4 outlook bar-graphs

The following graphs shows the average forecast value of NINO3.4 for each international model surveyed for the selected calendar month. If the bars on the graph are approaching or exceeding the blue dashed line, there is an increased risk of La Niña. Similarly, if the bars on the graph are approaching or exceeding the red dashed line, there is an increased chance of El Niño.

NINO3.4 bar graph month+1 NINO3.4 bar graph month+3 NINO3.4 bar graph month+5

IOD outlook bar-graphs

The following graph shows the average forecast value of the IOD index for each international model surveyed for the selected calendar month. If the majority of models are approaching or exceeding the blue dashed line, then there is an increased risk of a negative IOD event. If the majority of models are approaching or exceeding the red dashed line, then there is an increased risk of a positive IOD event.

IOD bar graph month+1 IOD bar graph month+3 IOD bar graph month+5

Past climate model summaries