SST for CFSRR Diane Stokes and Richard W. Reynolds

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SST for CFSRR Diane Stokes and Richard W.
Reynolds

• Brief overview of SST analyses used for Nov
  1981-2006
• Focus on Daily OI SST

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SST for CFSRR

• OIv2 1 Degree Weekly Analysis
• Optimum Interpolation
• Available Nov 1981 present
• OI 1/4 Degree Daily Analysis from NCDC
• Optimum Interpolation
• Currently available from 1985 - 2006
• Nov 1981-Dec 1984 Need daily AVHRR SST
  retrievals. (Pathfinder project may be working
  on this)

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OI SST Analyses
Weekly OI.v2 Grid 1o Data 7 days of satellite, ship buoy. Plus, SSTs simulated from 7-day median ice. Satellite data Infrared AVHRR 7-Day large-scale satellite bias correction (Poisson) Spatial error correlation 700 km Daily OI from NCDC Grid 0.25o Data 3 days satellite, ship buoy. Plus, SSTs simulated from 7-day median ice Satellite data Infrared AVHRR Microwave AMSR 7-Day large-scale satellite bias correction (EOTs) Spatial error correlation 100 km
Source Reynolds presentation at NOAA ARC PI
Meeting, Sep 2007, modified
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Source http//www.ncdc.noaa.gov/img/climate/resea
rch/sst/oi4.jpg
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Jan '03 Number of Days with Nighttime Obs

• Top AVHRR Pathfinder Bottom AMSR-E
• For AVHRR
• Absolute latitudes gt 40 have roughly only 5 days
  of data
• Number of days increases toward the tropics
• Drop offs due to cloud cover
• For AMSR
• Absolute latitudes gt 40 have more than 20 days
  of data
• Drop offs due to precipitation in ITCZ and SPCZ

Source Reynolds presentation at NOAA ARC PI
Meeting, Sep 2007
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Magnitude of GradientGulf Stream

• Daily OI using AMSR-E for January - March 2003
• Gradients have a stationary part due to
  topography
• Thus, limited AVHRR data are useful

Source Reynolds presentation at NOAA ARC PI
Meeting, Sep 2007
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Data Anomalies 11 Jan 2003Differences lead to
day-to-day noise in OI

• AVHRR day night
• Note data scarcity
• Pathfinder local time
• AMSR day night
• Note swath width precipitation
• Day night differences not always diurnal warming

Source Reynolds presentation at NOAA ARC PI
Meeting, Sep 2007
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4 Days of Buoy SST Data 0Z 22 March 22 - 0Z 26
March 26, 2006

• Resolution
• 1 minute
• Averaged to
• 1 hour
• 1 day
• Consider random sampling
• AMSR could approach 2 obs/day
• AVHRR would be lower especially in winter

Source Reynolds presentation at NOAA ARC PI
Meeting, Sep 2007
9
Average Daily Spectra for 3 Years

• Buoy spectra closer to daily OI spectra when
  3-days of data are used
• Note AVHRR-only lower than AMSRAVHRR
  spectra

Source Reynolds presentation at NOAA ARC PI
Meeting, Sep 2007
10
SST gradient magnitudes

• Three-day averages centered on 1 Oct 2003
• AMSRAVHRR Daily OI gradient most resembles AMSR
  data gradient
• AVHRR-only Daily OI does well despite poor data
  coverage.

Image Source Reynolds, R. W., T. M. Smith,
C.Liu, D. B. Chelton, K. S. Casey and M. G.
Schlax, 2007
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SST gradient magnitudes3-day average
As in previous slide, but for eastern Pacific
cold tongue
Image Source Reynolds, R. W., T. M. Smith,
C.Liu, D. B. Chelton, K. S. Casey and M. G.
Schlax, 2007
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Running in Real Time

• In real time, a preliminary and final version of
  the Daily OI SST would be produced.
• The final version would be delayed approximately
  two weeks to provide the wider data window for
  the satellite bias correction