ENSO Observations

Mike McPhaden NOAA/PMEL

Seattle, Washington

CLIVAR ENSO WorkshopParis, France

17-19 November 2010

ObservationsRequired for Description,

Understanding and Prediction

87%

Total in situ networks May 200860%

62%

81%

43%79%48%24%

Initial Global Ocean Observing System for Climate Status against the GCOS Implementation Plan and JCOMM targets

100%

100%

A Short History of ENSO Observations

Paleo Proxies Instrumental

1850s Matthew Fontaine Maury1950s IGY & Bjerknes1960s Satellite era for weather1980s AVHRR, Geosat altimetry1985-94 TOGA1990s High precision altimetry,

scatterometry 30 years of systematic subsurface ocean and

satellite observations for describing, analyzing and developing forecasting capabilities for ENSO

Current Conditions

http://www.pmel.noaa.gov/tao/

Current Conditions

http://www.pmel.noaa.gov/tao/

El Niño vs La Niña

http://www.pmel.noaa.gov/tao/

Recharge Oscillator Theory(Wyrtki, 1985; Cane et al, 1986; Jin, 1997)

Meinen & McPhaden, 2000

Build up of excess heat content along equator is a necessary precondition for El Niño to occur.

The time between El Niños is determined by the time to recharge.

El Niño purges excess heat to higher latitudes, which terminates the event.

Upper Ocean Heat Content and ENSO

After Meinen & McPhaden, 2000

Heat content based on TAO/TRITON, XBT and Argo data

Upper Ocean Heat Content and ENSO

Upper ocean heat content variations are the source of predictability for the ENSO cycle

Heat content based TAO/TRITON, XBT and Argo dataAfter Meinen & McPhaden, 2000

Lead Time Changes

Seasonality of Lead Time ChangesMcPhaden,, 2003: “Tropical Pacific Ocean heat content variations and ENSO persistence barriers.” GRL

Trends in Central Pacific El Niño SSTs

SST anomaly Dec 2009

Central Pacific El Niños are increasing in frequency

and amplitude

Lee & McPhaden, Geophys. Res. Lett., 2010

Niño-4 SST

EP vs CP El Niños

3/5 EP

3/4 CP

Ratio of CP/EP El Niños Increases Under Global Warming

20th century simulations21st century A1B scenario

Yeh et al, Nature, 2009Mean Thermocline Depth

Changes in Background Conditions

Differences in El Niño Composites

EP

CP

CP-EP

Mean State El Niño Statistics?

Mean ENSO?

Summary

30 years of systematic subsurface ocean and satellite observations available for detailed studies of ENSO and its decadal modulation

Lead time of ocean heat content (WWV) a predictor of ENSO SST has decreased from 2-3 seasons to ~1 season in the first decade of the 21st century

Loss of predictability concentrated early in the calendar year Changes correspond to increasing incidence of CP El Niños Corresponds to decadal changes in background conditions

(winds, thermocline depth, SST) Natural variability? Influence of global warming?

CLIVAR ENSO WorkshopParis, France

17-19 November 2010

And in the future?

Global Tropical Moored Buoy Array:A coordinated, sustained, multi-national effort to develop and implement moored buoy observing systems for climate research and forecasting throughout the global tropics

A contribution to GOOS, GCOS, and GEOSS

TRITONATLAS

Key attributes: Real-time Ocean-atmosphere High temporal resolution Basin scale

Eastern vs Central Pacific (“Modoki”) El Niños

Central Pacific(M

odoki)

Eastern Pacific

Ashok, 2009

Niño-3.4

Niño-4

A Short History of ENSO Observations

Paleo proxy Instrumental

1850s Matthew Fontaine Maury1950s IGY & Bjerknes1960s Satellite era for weather satellites1980s AVHRR, Geosat altimetry1985-94 TOGA1990s High precision altimetry, scatterometry