1. Beijing Climate Center/CMA
FOCRAII2017
ENSO Outlook in summer 2017
Yuan Yuan, Gao Hui
Beijing Climate Center/CMA
April 25, 2017

2. Outline
Recent monitoring and diagnoses
ENSO outlook

3. ENSO Standard in BCC Data: OISSTv2, monthly, 1⁰*1⁰
El Nino (La Nina) conditions: 3-mon-mean Nino3.4 ≥ 0.5℃ (≤ -0.5 ℃) for 3 consecutive months.
El Nino (La Nina) events: 3-mon-mean Nino3.4 ≥ 0.5℃ (≤ -0.5 ℃) for at least 5 consecutive months.

4. La Nina condition persisted for only 4 months (Aug-Nov 2016)

5. Monthly SSTA Distribution
201703
minus

6. Monthly Nino3.4 and SOI Nino3.4 Nino3 SOI 201612 -0.42 -0.37 0.4
201701
-0.32
-0.02
0.2
201702
0.13
0.63
0.0
201703
0.11
0.56
0.6

7. Weekly SSTA in Apr. 2017 (Daily OISST 0.25⁰×0.25 ⁰)
Apr minus Apr

8. Weekly Nino3.4 index Date Nino3.4 Nino3 Apr. 01-05 0.34 0.92
0.45
0.74
Apr
0.39
0.55
Apr
0.54
0.58

9. Weekly Heat Content Variation & Subsurface Temperature Anomalies
Ave. 5S-5N
Apr
Data: NOAA-GODAS

10. 850hPa Zonal Wind Anomalies & MJO Activities

11. Weekly OLR Anomalies (FY-3B data)
Apr
Active convection has been located in the equatorial western Pacific for a long time.
Recently, the convection in the equatorial eastern Pacific also became active.

12. Walker Cell Anomaly (5S-5N)
Apr
Mar. 2017
An intensified Walker circulation in Apr. 2017
However, the anomalous subsidence in central Pacific was weakened and the rising motion in eastern Pacific became stronger and moved westward as compared with Mar. 2017

13. Outline
Recent monitoring and diagnoses
ENSO outlook

14. Analogue-Dynamical correction
BCC-CSM1.1m
( )
201704
BCC-CSM1.1m
Analogue-Dynamical correction
MME
Statistic model
0.11℃
-2.0
-0.13
0.27K
Nino3.4
uflx
Warm Water Volumn
North Tropical Atlantic SST index

15. ENSO Outlook from different Models
IAP
CPC
BOM
TCC(Nino3)
ECMWF

16. Conclusions
In recent two weeks, the Nino3.4 index showed an increasing trend, and the convection gradually became active in the equatorial eastern Pacific.
BCC-CSM1.1m and most of other dynamic models indicated a warming trend of the Nino3.4 index in the following six months. However, special attention must be paid to the dynamic models as they have lower accuracy during this time of the year.
Based on the current monitoring of the atmosphere-ocean condition, and the predictions of dynamical/statistical climate models, the SSTs will be near or above normal in summer Whether an El Nino event will happen in the second half of the year depends on the outbreak of the westerly winds and the eastward propagation of the subsurface warm water in the tropical western Pacific during the next one or two months.

17. Thank You！