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This scientific study explores the inter-basin sources for the two-year predictability of the multi-year La Niña event in 2010-2012. It analyzes various factors such as Nino3.4 SSTA, sensitivity experiments, and impacts of warm Indian Ocean and Atlantic SSTA on La Niña prediction.
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Inter-basin sources for two-year predictability of the multi-year La Niña event in 2010-2012 Jing-Jia Luo (j.luo@bom.gov.au), Alves Oscar, Harry Hendon, and Toshio Yamagata Luo et al., 2017: Inter-basin sources for two-year predictability of the multi-year La Niña event in 2010–2012. Scientific Reports, DOI : 10.1038/s41598-017-01479-9.
Nino3.4 SSTA (120º-170ºW, 5ºS-5ºN,14 models, 1981-2001) Multi-model ENSO prediction: Luoand Leeet al. 2015
La Niña: • Bring cool and wet climate (floods) • Reduce global sea level • Scientifically interesting • Generally more predictable • ….
Multi-year prediction of La Niña: Nino3.4 SSTA; D20 (5˚S-5˚N, 150˚-270˚E) SSTA (˚C) D20a (m) Nino3.4 SSTA Nino3.4 SSTA SSTA (˚C) SSTA (˚C) Luo et al. J. Climate 2008
Real time forecasts (http://www.jamstec.go.jp/frsgc/research/d1/iod/e/seasonal/outlook.html) ENSO 2-year lead ENSO 2-year lead Obs. 1 Jan. 2010 1 Aug. 2009 ENSO 2-year lead ENSO 2-year lead 1 Jun. 2011 1 Jan. 2011
Observed SINTEX-F forecasts Rainfall anom. (mm) from 1Nov2010 Predicted from 1Apr2010 from 1Aug2010 Dec. 2010 – Feb. 2011 Predicted from 1Jul2010 from 1Sep2010 from 1Nov2010 Mar. – May 2011 mm/day
Nino3.4 SSTA; WWV (D20, 5ºS-5ºN, 150ºE-90ºW); U(5ºS-5ºN, 150ºE-160ºW)
dU/dt (5ºS-5ºN, 150ºE-160ºW); IO SSTA (20ºS-20ºN,40ºE-120ºE); Atl SSTA (20ºS-20ºN,70ºW-15ºE) dU/dt = a × IO SSTA + b × Atl SSTA R=0.59
2-year prediction of 2010-12 La Niña: (9-member mean) (20-member mean)
(20ºS-20ºN, 40ºE-120ºE) (20ºS-20ºN, 70ºW-15ºE)
Sensitivity prediction experiments using SINTEX-F (9 members, initiated from every month during Jan 2010-Dec 2011) • IO SSTA impact • i) Specify observed SST in the Indian Ocean (20ºS-20ºN, 40ºE-120ºE) • ii) Specify observed climatological SST in the IO • IO + Atlantic SSTA impact • i) Specify observed SST in both the IO and Atlantic (20ºS-20ºN, 70ºW-15ºE) • ii) Specify observed climatological SST in both the IO and Atlantic
2-year lead ENSO prediction (SINTEX-F, 1982-2004): Nino3.4 SSTA prediction (120º-170ºW, 5ºS-5ºN) 0.5 Ensemble mean Each member Persistence Lead time (month) Luo et al., J. Climate, 2008.
A possible reason for the 2-year predictability of 2010-12 La Niña: Impacts of warm IO SSTA on the La Niña prediction Impacts of warm Atlantic-IO SSTA on the La Niña prediction Nino3.4 SSTA U10m (150˚-200˚E, 5˚S-5˚N)
Summary: • The warm SSTA in both the Atlantic and Indian Ocean may play an important role in the double-peaked La Niña in 2010-12 (in addition to local air-sea interactions). • Implication for the predictability and future change under global warming.
Work in progress (ACCESS-S:0.25ºL75 NEMO, N216L85 UM) Red: ensemble mean; grey: each member; blue: persistence