SST for CFSRR Diane Stokes

and Richard W. Reynolds

• Brief overview of SST analyses used for Nov 1981-2006

• Focus on Daily OI SST

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)

OI SST AnalysesWeekly 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 (EOT’s)

• Spatial error correlation: ~ 100 km

Source: Reynolds presentation at NOAA ARC PI Meeting, Sep 2007, modified

Source: http://www.ncdc.noaa.gov/img/climate/research/sst/oi4.jpg

• Top: AVHRR Pathfinder Bottom: AMSR-E

• For AVHRR:• Absolute latitudes > 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 > 40° have

more than 20 days of data

• Drop offs due to precipitation in ITCZ and SPCZ

Jan '03: Number of Days with Nighttime Obs

Source: Reynolds presentation at NOAA ARC PI Meeting, Sep 2007

Magnitude of Gradient:Gulf 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

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

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

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 AMSR+AVHRR spectra

Source: Reynolds presentation at NOAA ARC PI Meeting, Sep 2007

SST gradient magnitudes

• Three-day averages centered on 1 Oct 2003

• AMSR&AVHRR 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

SST gradient magnitudes3-day average

Image Source: Reynolds, R. W., T. M. Smith, C.Liu, D. B. Chelton, K. S. Casey and M. G. Schlax, 2007

As in previous slide, but for eastern Pacific cold tongue

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