ENSO Outlook in spring/summer 2013 Beijing Climate Center/CMA Rongqing Han Hello, it's my pleasure to meet you all. I am Han Rongqing. I am from NCC of CMA Beijing Climate Center/CMA April 9, 2013

Outline Influences of Climatological background Trend Diagnoses of zonal tropical wind Impacts of the North Pacific SST Models’ prediction Discussion and Conclusion As follows

1. Influences of Climatological background Trend

Global SST Anomaly (0C) and Anomaly Tendency

Stronger Walker cell in recent years Feb Mar 2012 2013

And Stronger meridional cells Feb Mar 2012 2013

Correlation between Monthly Nino3 Correlation between Monthly Nino3.4 index & January Siberian High (1981-2011) 95%confidence 90% confidence Correlations 95% Concurrent year, yesteryear, following year 99%confidence Y（-1） Y（0） Y（+1） Month for Nino3.4 index

Negative Siberian high index in January 2013 will be favor of the warmer Nino SST in later months

NINO3.4 Heat Budget (from CPC) SSTA tendency (dT/dt) in NINO3.4 region (dotted black line) was positive, but decreased in Mar 2013. All the advection terms, as well as thermodynamical term (Qq) were positive, consistent with weakening of negative SSTA Huang, B., Y. Xue, X. Zhang, A. Kumar, and M. J. McPhaden, 2010 : The NCEP GODAS ocean analysis of the tropical Pacific mixed layer heat budget on seasonal to interannual time scales, J. Climate., 23, 4901-4925. Qu: Zonal advection; Qv: Meridional advection; Qw: Vertical entrainment; Qzz: Vertical diffusion Qq: (Qnet - Qpen + Qcorr)/ρcph; Qnet = SW + LW + LH +SH; Qpen: SW penetration; Qcorr: Flux correction due to relaxation to OI SST

Depth anomaly of 20℃ isotherm in the tropical Pacific Time

2. Diagnoses of zonal tropical wind (5S-5N) Composite of Transition to La Nina events Composite of Transition to El Nino events The current 时 间

2. Diagnoses of zonal tropical wind (5S-5N) Composite of persisting on ENSO-neutral and warmer conditions Composite of persisting on ENSO-neutral and colder conditions The current

3 Impacts of the North Pacific SST ------------by wind-evaporation-SST mechanism

4. Models' prediction

Average of international model outlooks for NINO3 Average of international model outlooks for NINO3.4 ----------- 7 dynamical models ensembled by Australia

Models’ prediction of IRI/CPC

CPC Models' prediction

5. Discussion and Conclusion Advantages for El Nino Disadvantages for El Nino Siberian high and tropical wind are favor of El Nino developing in the second half of 2013 Lasting recharge effect in the tropical Pacific since 2010,with two La Nina events and a neutral year, is prepared enough for next El Nino Lasting negative phase of PDO Stronger positive Walker and Hadley cells Influence of negative SST anomalies in the northeastern Pacific

5. Discussion and Conclusion ENSO is most likely to turn gradually into warm and neutral conditions by following summer; Negative SST anomalies are expect to only remain in the central tropical Pacific by summer 2013. It would be a higher probability for El Nino event occurring in next autumn than that in last year.

Thanks!