Contents

1. What is El Niño ?

2. Evolution of 2002/03 El Nino

3. Current system for monitoring and prediction of El Niño in JMA

4. Current El Niño condition and outlook

El Niño Monitoring and Prediction in JMA

El Niño Monitoring and Prediction in JMA

What is El Nino ?

November 1997November 1997

El Nino 1997/98

What is “El Niño” ?

（１） warm current each year around Christmas along the coast of Ecuador and Peru ： lasting only a few weeks to a month or more

（２） condition warmer than normal in the eastern equatorial Pacific at intervals of several years: lasting about 12-18 months

⇔ 　“ La Niña” = “The girl“ in Spanish

　“ The Boy” in Spanish = “The Chist child”

Mean Sea Surface Temperature in equatorial Pacific

January

April

July

October

1. West > East throughout year, almost constant in West

2. Autumn = Annual minimun in East => Largest difference

3. Largely increase and reach peak in Spring

Normal condition of the equatorial Pacific

Easterly= Trade wind

Active Convection

Thermocline

Mixed Layer(warm)Deep Water(cool)

Upwelling

From : NOAA homepage

Equator

Warm water

Walker Circulation

SST contribute to tropical rainfall and convective

activity

Westerly

Low sea level pressure ascending motion

High sea level pressure decending motion

Colder water up from deeper level to replace surface water

Slopes upward the surface farther east

Deepest in the west

Heavy rain

Least rain

Ｂ： Normal (November)Ａ： El Niño (November 1997)

Ａ－Ｂ :Anomaly

SST in El Niño vs NormalSST in El Niño vs Normal

El Niño :

Warmer than normal in the eastern equatorial Pacific

band of warm water were

observed along the eq. Cooler water in East

Ｂ： Normal (November)Ａ： La Niña (November 1988)

Ａ－Ｂ :Anomaly

SST in La Nina vs NormalSST in La Nina vs Normal

La Niña :

Cooler than normal in the eastern equatorial Pacific

Similar pattern as normal warmer than normal in west , cooler in east

El Niño Monitoring Area 　

（ 4S-4N,150W-90W ）

JMA’s definition

The departure of the monitoring area SST from

the1961-1990 average with five months running mean

・ above +0.5 C for six months or longer : El Niño

・ beneath –0.5 C for six months or longer : La Niña

El Niño La Niña

Sea Surface Temperature deviation from 1961-1990 mean

1980

1990

2000

1985

1995

0

-3

3

0

-3

3

0

-3

3

（℃）

（℃）

（℃）

El Nino Monitoring Area (Region B)

（ 4S-4N,150W-90W ）

El Nino

La Nina

2005

1997/98

1982/83

El Nino / La Nina:・ develop every 2 ～7 years・ last for 12 months ～ half a year

Southern Oscillation

= Large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific

Sea

surf

ace

pres

sure

Sea surface pressure anomaly at Darwin and Tahiti

DARWIN TAHITI

Clearest sign = inverse relationship between of Psea at TAHITI and DARWIN

Standeng wave

Sea-saw = mass of air oscillation back and forth across the date line in t

ropics

Pattern reverse every few

years

High pressure at one site is almost always concurrent with low at

other site

SOI ( Southern Oscillation Index ) : Trade Wind

Strong

weak

AtmosphereAtmosphere

warm

cool

OceanOcean Region B SST deviation from 1961-1990 mean

El Nino Southern Oscillation (ENSO)

Fluctuation in SST during ElNino and LaNina are accompanied by S

O

Negative SO = D>T positive rB. Positive SO = D<T negative rB. = Oppsite phase

El Nino and SO are deferent manifestation of single phen

omenon

Atmosphere - ocean condition of El Nino

Weaken trade wind

Warm water move eastward

SST increase in the east

Active convection area move eastward

From : NOAA homepage

Normal El Nino

EQ

El Nino Walker Circulation is displaced

Upwelling weaken, gradient of thermocline reduced

Outgoing Long-wave Radiation (OLR)

El Nino (Nov. 1997)

Normal (1979-2000)

ActiveInactive

Small (large) value = active (inactive) convective activity

850hPa Wind

Weak Trade wind

Subsurface temperature along EQ in El Nino

Nov.97

Normal

Anomaly

Sea surface temperature Subsurface temperature

Subsurface temperature along EQ in El NinoTemperature

Early stage (Jan97)

Mature stage (Nov97)

Latter stage (May98)

Themocline is deeper than normal in western and central eq. Pacific = deep pool of warm ocean

Depth of themocline reduce in western and central eq. Pacific and increase in East subsurface temp. increase in c

entral and eastern Pacific

Depth of themocline and subsurface temp. reduce thr

oughout most of eq.

Thermocline is where contour is crowed (green)Anomaly

OHC anomaly

OHC (Ocean Heat Content)

= vertically averaged temperature in the top 260 m => depth of thermoclineOHC

Ocean and Atmosphere in Normal vs El Nino

Normal El Nino

SST Warm in West Cool in East

Increase in East

convective precipitation

western Pacific

Move to central Pacific

Trade wind Strong (easterly)

weak

Walker Circulation

Over western Pacific

Displaced eastward

Warm water Deep in West Move eastward

Thermocline Slant from East to West

Reduced gradient

　 Mature Stage of 1997/98 El NiñoNiño

Sea Surface Temperature

Ocean Temperature along Equator

Ocean Subsurface changes lead to El Niño evolutionNiño evolution

animation

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•Tropics （ Directly ） Eastward shift of convective precipitation → Dry condition in the west and flood in the west 　 　　　 Indian monsoon precipitation less than normal (northern summer)

•Mid-latitude （ Indirectly ）

El Nino impact to the world climate

EQ

Normal El Nino

Climate characteristics in ENSO Warm Events

　　　 Hot 　 Cold 　 Wet Dry 　　　

NO DATA

NO DATA

NO

DATA

World Climate in El Nino (December - February)World Climate in El Nino (December - February)（ 12 event in 1951 ～ 1996 ）

Comvective precipitation area move eastward = Dryer in the central eq. Pacific, wetter in the western eq. Pacific

Warm in almost the tropical region

（ 12 event in 1951 ～ 1996 ）World Climate in El Nino (June - August)World Climate in El Nino (June - August)

Climate characteristics in ENSO Warm Events 　　　 Hot 　 Cold 　 Wet Dry 　　　

Drier than normal in west and wetter in the central. Indian monsoon is weak

increased heat over central and eastern eq. Pacific affect atmosphere circulation in su

btropics and mid-latitude (ex. jet-stream move southward in boreal summer)

How does El Nino influence the climate in your country ?

El Niño and Climate in JapanEl Niño and Climate in Japan

0% 20% 40% 60% 80% 100%Oki nawa

Kyushu

Shi koku

Chugoku

Kantou

Touhoku

Earl y

Normal

Late

0% 20% 40% 60% 80% 100%

Oki nawa

Wast J apan

East J apan

North J apanLowNormalHi gh

Late End of the Rainy Season (June - July)

Cool Summer

Warm Winter

Evolution of El Nino 2002/03

Time Series of Region A and Region B SST anomaly

+1.4 CNov. 02

+1.2 CNov. 02

Compared with past events

2002/03 El Nino:

• Moderate in RegionB

•Highest in Region A

4 seasons

Mar.02

Nov.02

Mar.03

SST anomaly in equatorial PacificSST anomaly in equatorial Pacific

•Mar 2002 … negative anomalies were found in east and temporally positive anomalies off South America

•Late May 2002… due to MJO (strong westerly wind), SST anomaly in East increase (> +1C appeared)

•Nov 2002 … positive anomalies > +1C was widely found in the center and east.

•Mar 2003 … negative anomalies appear in east and positive anomaly shrink in central.

Mar.02

Nov.02

Mar.03

Subsurface Temperature anomalySubsurface Temperature anomaly

•Mar 2002 …positive anomalies (occurred by MJO in Dec.01) reached coast of South America

•July, August, October 2002… MJO induced eastward propagation of Kelvin wave. SST anomaly in East increase

•Nov 2002 … negative anomalies spread in west and contrast between E and W was distinct.

•Mar 2003 … positive anomalies shrank in east and negative anomalies partly appeared.

Consistent with ongoing El Nino

Drier than normal : Indonesia, northern and eastern Australia

Wetter than normal : central equatorial Pacific, southeast South America

OLR anomalyOLR anomaly

December. 2002180120E 90W

Only for 2 months

time

2002/03 El Nino evolution along the equator

OHC Anomaly SST Anomaly

(time-longitude cross section)

mature

Africa Indonesia America

E W

Madden-Julian Oscillation (MJO)

Tropical Intraseasonal Oscillation (20N-20S max.:EQ)

These fluctuations in tropical rainfall often go through an entire cycle in 30-60 days

=> Assiciated global –scale, zonally oriented circulation cell propagated eastward 　

Convergence at low level

Easterly ot Westerly sometimes contribute to El Nino

Schematic diagram of lon-time structure of MJO

time

2002/03 El Nino evolution along the equator

OHC Anomaly

(time-longitude cross section)

Westerly burst associated with MJO induced eastward propagation of

Kelvin wave

U850 　Anomaly

2002/03 (SON) composite (SON)

SST anomaly

OHC anomaly

SST: 72,76,82,86,91,97

OHC: 86,91,93,97

El Nino 2002/03 vs Composite map

2002/03 warmer in Central and cooler than Eastern

Current system for monitoring and prediction of El Niño in JMA

Ocean DataAssimilation

System (ODAS)

Coupled AtmosphereOcean General Circulation

Model

Ocean Initial Cond. NINO.3 SST Anomaly

SST XBT TAO/TRITON

Sea Surface Height

Wind Stress Heat and Water Fluxes

Model Output Statistics(MOS)

Analysis of latestatmosphere-ocean

conditions

Official SST Forecast

・ El Nino Monitoring Report ・ “ El Nino Monitoring and Outlook” (WMO/DDB & TCC) ・ Climate Monitoring Report・ Monthly Ocean Report

JMA EL NIÑO MONITORING AND PREDICTION SYSTEM

Observation

El Niño

Monitoring

El Niño

PredictionPublic Announcement

Atmos. Initial Cond.Argo

DynamicalSeasonalForecast

Atmospheric GCM

Ocean GCM

Coupled

GCM

New E ｌ　 Niño Forecast Model (JMA-CGCM02)

Flux Adjustment One Day Coupling

Ocean Data Assimilation System

Initiali- zation

Data Assimilation System

7 Months Forecast

MOS Corrected NINO3 SSTA

･ T42L40･ Arakawa-Schubert･ SiB

･ 2.5 x 0.5 ～ 2.0 L21･ Bryan-Cox type･ Closure Mixing

T213 L40

Observed Temp, Salinity, Sea Level Height

IAU (Incremental Analysis Update)

LAF, 6 initials

３ DVAR

Since July 2003

Assimilated data

Run twice a month

( 1988Feb-2000Jan, 96exps. )ACC RMSE

ReginB(NINO3)

ReginD(NINO.WEST)

Cgcm02 is higher than Cgcm01 especially up to 5-9 months

Cgcm02 is smaller than Cgcm01

Skill of Region B is better than that of Region D

Predictor: Initial B SST OHC (6S, Eq,6N) Zonal Wind Stress (Eq) SST (Eq) Forecast B SST OHC (6S, Eq,6N) Zonal Wind Stress (Eq) SST (Eq) Lead time Calendar month

Predictand: Regin B (Nino 3) SST

MOS: Stepwise Regression Analysis

②OHC　 (160E,6N)

① 　 B 　SST

Choose 11/73 predictor

Gravest contributor

A C

C

Lead 　Time 　（ month)

RM

SE

()

℃

ACC (CGCM) ACC (MOS)

RMSE (CGCM) RMSE (MOS)

Region B SST Skill ACC

MOS 　 remain above 0.8 until 9 months lead time

RMSE

MOS reduce and remain 0.5C up to 8 months lead time

Calculated from 96 hindcast

experiments (1988- )

Before & after MOS correction

El Nino product on TCC Homepage

El NiEl Niñño Information of JMAo Information of JMA

• WMO Distributed Data Bases (http://ddb.kishou.go.jp)

• Tokyo Climate Center HP (http://okdk.kishou.go.jp)

Main changes :Addition of Summary

Enhancement of Atmosphere ComponentOLR Index (OLR-DL, U200-CP, U850-CP)200hPa velocity potential anomaly850hPa zonal wind anomaly

Renewal of TCC Homepage !Renewal of TCC Homepage ! December 2003 December 2003 ～～

We recommend JMA El Nino Product, because ...

ADIOS A EL NIÑO, HOLA A LA NIÑA

May 19, 2003 — On the heels of El Niño’s departure the world could soon be facing the return of La Niña say scientists at NOAA. Based on current sea surface temperatures and recent atmospheric and oceanic trends in the tropical Pacific, it is likely that La Niña will develop over the next few months…….

Press release of NOAA

After that, how did the equatorial Pacific SST Anomalies change ?

•During May to June, a temporary cooling was found in the east.

• In the late September to October, positive anomalies appeared across the central and eastern equatorial Pacific.

NO La Nina !!Shall we get El Nino products

from many sources ?

El Nino 2002/03

Current Diagnosis and Outlook

Sea Surface Temperature (October 2003)Current Diagnosis

RegionB

+0.2 (S) => +0.6(O)

Sub Surface Temperature (October 2003)Current Diagnosis

El Nino Outlook (Nov. 2003 – May 2003)

The Region B (Nino 3) SST is likely to be around normal in this autumn and winter.

It will possibly be slightly warmer than normal afterwards until May 2004.

SummarySummary

• El Nino Southern Oscillation (ENSO) is a interannual climate variation of the ocean-atmosphere system in the tropical Pacific.

• Each El Nino/La Nina event is different.

• Would you check the El Nino product of TCC Homepage, always or sometime ?

Thank you

Monthly El Niño Monitoring Report

Ocean Data Assimilation System

El Niño Forecasting model(Atmosphere and Ocean Coupled Model)

Global Ocean Surface and Subsurface Data

Long- range Forecast of Japan

Every day

Twice a month

JMA EL NIÑO MONITORING AND PREDICTION SYSTEMJMA EL NIÑO MONITORING AND PREDICTION SYSTEM

Subsurface observation Subsurface observation datadata （（ September.2003September.2003 ））

:70 buoys

Observation is insufficient

Data Assimilation

SST Monitoring in Regions A-D

Region A: 4N-4S, 160E-150W

Region B: 4N-4S, 150W-90W

Region C: EQ-10S, 90W-80W

Region D: 14N-EQ,, 130E-150E