Ocean State Estimation for Global Ocean Monitoring:
ENSO and Beyond ENSO
Yan Xue
Michael J. McPhaden
Tong Lee
Magdalena Balmaseda
Oscar Alves
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NCEP/NOAA (USA)
PMEL/NOAA (USA)
JPL/NASA (USA)
ECMWF (U.K.)
BOM (Australia)
JMA
Yan.Xue@noaa.gov
Michael.J.Mcphaden@noaa.gov
tlee@jpl.nasa.gov
Magdalena.Balmaseda@ecmwf.int
O.Alves@bom.gov.au
______________________________________________________________________
Ocean state estimation has been significantly improved in the past decade due to many
advances in data assimilation schemes and dramatic increases in observations. Ocean state
estimation has being used to provide ocean initialization for seasonal forecast models and to
monitor the thermal structures of ENSO in the tropical Pacific. The later is particularly
important since model forecast uncertainties are still large. Advanced ocean monitoring tools
such as those based on ENSO theories and mixed layer heat budget are being pursed, which
could potentially improve operational ENSO forecasts. Routine expert assessments and model
predictions of climate variability beyond ENSO such as Indian Ocean Dipole, Tropical
Atlantic Variability, and Pacific Decadal Oscillation (PDO) are beginning to be pursed by
operational centers and research institutes. To understand impacts of climate variability on
biological productivity, routine monitoring of coastal upwelling using ocean state estimation
and assessing its relationship with climate variability such as ENSO and PDO is also being
pursed.
1. Introduction to global ocean monitoring
GODAS web site (http://www.cpc.ncep.noaa.gov/products/GODAS/)
2. Monitoring tropical Pacific ENSO by operational centers
a. NCEP (http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml)
b. JMA (http://ddb.kishou.go.jp/climate/ElNino/elmonout.html#outlook)
c. ECMWF (http://www.ecmwf.int/products/forecasts/d/charts/ocean/)
d. BOM(http://www.bom.gov.au/climate/enso/)
3. Understanding ENSO
a. Physical processes
1. Equatorial recharge-discharge of heat content
WWV index (http://www.pmel.noaa.gov/tao/elnino/wwv/)
2. Wave reflection from western boundary
3. Zonal advection of warm pool
4. Madden-Julian Oscillation and ENSO relationship
5. Changes of ENSO and global warming
b. Mixed layer heat budget
4. Supporting operational ENSO forecasting
a. Enhancing ocean monitoring tools
1. Recharge-discharge and Zonal advection
2. Mixed layer heat budget analysis in real time
Fig. 1 Mixed layer heat budget analysis for ENSO in real time.
b.
Estimating uncertainties in ocean initialization
(link to Magdalena Balmaseda White Paper)
5. Looking beyond ENSO
a. Upper ocean heat content variability
Fig. 2. Time series of averaged temperature anomalies in upper 300m in selected areas from 1981 to
present. ECMWF ocean analysis is used here. The final figure will include contributions from NCEP
GODAS, BOM’s ocean analysis, JMA’s ocean analysis. Note the decrease of the last few years of the
heat content in the North Subtropical Atlantic, the abrupt shift in the North Pacific in the late 80’s, the
positive Indian Ocean dipole during La Nina 2008. Also note the stabilization of the warming trend in the
global ocean and North Atlantic in the last few years.
b.
c.
d.
e.
f.
IOD (http://www.jamstec.go.jp/frsgc/research/d1/iod)
TAV(CPC ocean briefing)
PDO (CPC ocean briefing)
AMOC
Coastal upwelling (CPC ocean briefing)
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