Post on 24-Feb-2016
description
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