BLUElink> Regional High-Resolution SST Analysis System

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BLUElinkgt Regional High-Resolution SST Analysis
System Verification and Inter-Comparison

• Helen Beggs
• Ocean Marine Forecasting Group,
• BMRC, Bureau of Meteorology
• Presented at 8th GHRSST-PP Science Team Meeting,
  Melbourne, 14-18 May 2007

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BLUElinkgt Regional High-Resolution SST Analysis
System

• Based on BoM operational, optimal interpolation
  SST analysis system
• Resolution Daily, 1/12
• Region 60E - 170W , 20N - 70S
• Data sources
• AVHRR SST1m (Local 1km, Global 9km x 4 km)
• AATSR Meteo SSTskin (17km)
• AMSR-E SSTsubskin L2P (25 km)
• In situ bulk SST from GTS
• NCEP ice edge data

Test daily foundation SST analyses available by
0230 UT (fv01) and 2030 UT (fv02) as GHRSST-PP
GDS v1.7 netCDF L4 files from OPeNDAP server
accessible via http//godae.bom.gov.au More
information on the analysis system
http//www.bom.gov.au/bmrc/ocean/BLUElink/SST/Bur
eau_HR_Regional_SST_Analysis_vg1.0.pdf
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How does BLUElinkgt test 1/12 regional SSTfnd
analysis compare with other SST analyses/composite
products over the same region (20N to 70S,
60E to 170W)?
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Data Inputs to L4/L3 SST products over Australian
region
L4/L3 Product GAC AVHRR (1m) HRPT AVHRR (1m) AMSR-E (subskin) AATSR (skin) TMI (subskin) In Situ (bulk)
BoM 1/12 regional SSTfnd X X X X X
BoM 1/4 regional SST1m X X X
OSTIA 1/20 global SSTfnd X X X X X
Reynolds 1/4 AMSRAVHRR SSTblend X X X
CSIRO 1/25 3 Day AVHRR Composite SST1m X
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BoM Operational Regional SST1m
Reynolds AMSR-EAVHRR SSTblend
CSIRO 3 Day AVHRR SST1m
Met Office Global OSTIA SSTfnd
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Reynolds AMSR-EAVHRR SSTblend minus OSTIA SSTfnd
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BoM Gamma Test SSTfnd Analysis minus Other SST
Analyses/Composites

• Over region 60E - 180E , 20N - 70S
• Period 1 Oct 30 Nov 2006
• Test BoM Operational Regional SST1m 0.07
  0.41C
• Test CMAR Composite AVHRR SST1m -0.15
  0.73C
• Test OSTIA SSTfnd 0.09 0.45C
• Test Reynolds SSTblend -0.02 0.61C

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How do we assess how good analyses are?
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GODAE Level 4 Analysis Metrics

• Performance Analysis
• Diagnostics based on statistical measures
• Innovation Vector (Obs - BGF and rms(Obs BGF))
• Withheld Observations (Analysis (no buoy data)
  Buoy SST)
• Quality Analysis
• Based on direct comparisons with observations
• Consistency Analysis
• Based on understanding of ocean
• Can use animations

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Performance Analysis BoM Analysis Statistics
1 Oct 30 Nov 2006

• Operational SST1m
• Beta Test SSTfnd
• Gamma Test SSTfnd

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Quality Analysis Analysis/Composite SST minus
Buoy SSTfnd

• Over region 60E - 180E , 20N - 70S
• Period 1 Oct 30 Nov 2006
• BoM Operational Regional SST1m -0.08 0.44C
• BoM Beta Test Regional SSTfnd -0.08 0.42C
• BoM Gamma Test Regional SSTfnd -0.01 0.29C
  (0.03 0.49C)
• CMAR Composite AVHRR SST1m -0.01 0.62C
• OSTIA SSTfnd -0.07 0.24C
• Reynolds AMSR-EAVHRR SSTblend -0.04 0.52C

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Consistency analysis
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NOAA Daily Reynolds SSTblend
BoM Daily Gamma Test Regional SSTfnd
CSIRO 3 Day Daily AVHRR SST1m
Met Office Daily Global OSTIA SSTfnd
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NOAA Daily Reynolds SSTblend
BoM Daily Gamma Test Regional SSTfnd
BoM Operational Regional SST1m
Met Office Daily Global OSTIA SSTfnd
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NOAA Daily Reynolds SSTblend
BoM Daily Gamma Test Regional SSTfnd
CSIRO 3 Day Daily AVHRR SST1m
Met Office Daily Global OSTIA SSTfnd
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Conclusions

• Over the study period (1 Oct 30 Nov 2006) BoM
  Gamma Test SSTfnd Analyses
• Have less bias and RMS error than BoM Operational
  or Beta Test Regional SST analyses (based on Obs
  Analysis, Obs BGF and Analysis Buoy Obs)
• Agree more closely with OSTIA SSTfnd analyses
  than Reynolds AMSR-EAVHRR SSTblend or CSIROs 3
  Day AVHRR SST1m Composite
• More closely resolve meso-scale ocean features
  than 1/20 resolution OSTIA SSTfnd analyses
• Exhibit better temporal consistency between daily
  analyses but less spatial homogeneity than OSTIA
• Parallel tests with LAPS0.125 and LAPS0.05
  (Sydney) ingesting Gamma SSTfnd and BoM
  operational regional SST1m currently underway to
  determine impact on skill.

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NOAA Daily Reynolds SSTblend
Gamma Test SSTfnd (BGFCLS 50 km)
CSIRO 3 Day Daily AVHRR SST1m
Met Office Daily Global OSTIA SSTfnd
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NOAA Daily Reynolds SSTblend
BoM Daily Gamma Test Regional SSTfnd
CSIRO 3 Day Daily AVHRR SST1m
Met Office Daily Global OSTIA SSTfnd
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BLUElink SSTfnd Analysis Blending Method
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Filtering for Diurnal Warming Events (1 30 Nov
2006 60E - 190E , 20N - 70S)
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Filtering for Diurnal Warming Events (1 30 Nov
2006 60E - 190E , 20N - 70S)