1.SSTs for 2005 2.Daily SST OI

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1. SSTs for 20052. Daily SST OI
Richard W. Reynolds (NOAA, NCDC)
NOAAs National Climatic Data Center Asheville, NC
OAA Climate Observation Program 4th Annual System
Review Silver Spring, Maryland May 10-12,
2006
2
SST Anomalies

• Top 2004 Anomaly
• Bottom 2005 Anomaly
• Base Period 1971-2000
• Differences
• Slight change in weak ENSO
• Shift in Tropical North Atlantic positive
  anomalies
• Similarities
• Northern high latitude positive anomalies
  60N

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Zonal SST Anomalies

• Period Jan '97 - Apr '06
• 1997-98 El Niño
• Peak Jan 1998
• Strong northern high latitude positive SST
  anomalies in Boreal Summers '03 - '05
• Peak anomaly similar to ENSO but surface area
  smaller
• '05 less intense than '03 and '04
• Persistent modest northern middle latitude
  positive SST anomalies for record

NOTE
Time
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Zonal SST Anomalies

• Period Jan '82 - Apr '06
• 1982-83, 1987-88, 1997-98, major El Niño events
• Northern high latitude positive SST anomalies
• not evident before 1997
• Persistent northern middle latitude positive SST
  anomalies
• not evident before 1998
• Clear evidence of warming trend with time between
  20S and 80N

NOTE
Time
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Monthly SST

• Left July - Sept '04
• Right July - Sept '05
• Anomalies shaded
• Isotherms 26-28ºC
• SSTs needed for hurricane formation roughly gt
  26.5ºC
• Areas above 28ºC larger in 2005 than 2004
• Warmer anomalies tend to lie in these areas in
  2005

NOTE
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2. Daily SST OI
Richard W. Reynolds (NOAA, NCDC) Thomas M. Smith
(NOAA, NCDC) Kenneth S. Casey (NOAA, NODC) Dudley
Chelton (Oregon State University)
NOAAs National Climatic Data Center Asheville, NC
OAA Climate Observation Program 4th Annual System
Review Silver Spring, Maryland May 10-12,
2006
7
Jan '03 Number of Days with Nighttime Obson
0.25 grid

• 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

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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

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OI SST Analysis
Weekly (OI.v2) Grid 1o Data Satellite plus in situ (ship and buoy) data Satellite data Infrared AVHRR 7-Day large-scale satellite bias correction for each satellite Spatial error correlation 700 km Daily Grid 0.25o Data Satellite plus in situ (ship and buoy) data Satellite data to include Infrared AVHRR Microwave AMSR-E 7-Day large-scale satellite bias correction for each satellite Spatial error correlation 100 km
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Jan 2003 Standard Deviation
Top Pathfinder Bottom AMSR-E

• AMSR-E has stronger standard deviations than
  Pathfinder
• Especially in mid-latitude winter
• Clouds reduce Pathfinder sampling
• These differences plus gradient differences
  suggest that separate Pathfinder OI and
  Pathfinder AMSR OI needed

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Nighttime Zonal Bias AVHRR - In Situ
90N
AVHRR Pathfinder - In Situ
90S
'82
'05
90N
AVHRR Operational - In Situ
90S
Pathfinder Advantages Lower bias variability
data delayed Operational Advantages Real-time
data 1981-84 data
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Weekly Daily OIDecember 1991

• Both OIs have bias correction for AVHRR data
• Daily OI uses Pathfinder
• Weekly OI uses Operational
• From the figure note
• Operational data problem along 35oS
• Delayed mode processing allows data correction
• Daily scales reduced in high gradient areas

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Weekly Daily OIJanuary 1998

• Both OIs have bias correction for AVHRR data
• Daily OI uses Pathfinder
• Weekly OI uses Operational
• From the figure note
• Pathfinder problem near equator in Eastern
  Pacific
• Zonal bias in Pathfinder worse than Operational
• Number of AVHRR retrievals lower than normal due
  to ENSO cloud cover

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OI Anomalies with Bias CorrectionJanuary 1988
Along equator

• From the figure note
• Operational AVHRR did not have strong biases in
  this region
• Negative biases in daily OI except at TAO mooring
  sites near 155oW, 140oW 125oW
• OI bias correction fails to correct AVHRR
  Pathfinder satellite biases

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OI Anomalies with Bias CorrectionJanuary 1988
Along equator

• From the figure note
• Operational AVHRR did not have strong biases in
  this region
• Negative biases in daily OI except at TAO mooring
  sites near 155oW, 140oW 125oW
• OI bias correction fails to correct AVHRR
  Pathfinder satellite biases
• Empirical Orthogonal Teleconnections (EOT) bias
  correction better at correcting biases

Daily OI computed with EOT bias correction
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Daily Bias Differences 1 Jan '03 - 31 Dec '04
EOTs reduce biases Some residuals remain
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Daily OI Ship Biases

• Satellite Biases are corrected with respect to in
  situ data (ships buoys)
• Ships have larger random and bias errors than
  buoys
• Ship observations using buckets tend to be
  biased cold due to evaporation
• Ship observations using engine intake tend to be
  biased warm due to engine room heating
• Ship metadata needs improvement
• Try to correct ship bias using buoy data
• Preliminary tests indicate EOT procedures over a
  45-60 day time period would work

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Ship-Buoy SST Zonal Biases
Annual Ship - Buoy Bias
'94

• EOT monthly ship buoy analyses
• Buoy SST obs increase with time
• Significant buoy obs 1994 to present
• Care required to first correct in situ biases
  than satellite biases
• Easier to correct buoys with respect to ships
  than inverse
• NOT IMPLEMENTED !!

Time
'05
60S
60N
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Daily OI Status

• Daily OI analysis computed on 0.25 grid with and
  without satellite EOT bias correction
• Using Pathfinder AVHRR from 4 Jan 1985 to 31
  December 2005
• Using Operational AVHRR from 1 Jan 2006 to
  present
• Using AMSR-E from 1 Jun 2002 to 31 Dec 2005
• Using Pathfinder AVHRR AMSR-E from 1 Jun 2002
  to 31 Dec 2005
• Future Plans
• Add error estimate field to OI
• Improve sea ice concentrations and generation of
  SSTs from sea ice
• Put output files in NetCDF
• Make OI operational

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Daily OI SST AnomaliesEOT satellite bias
correction
Left Pathfinder AVHRR OI Right Pathfinder
AVHRR AMSR-E OI

• 27 August Katrina
• Weak anomaly in Gulf in Path AMSR-E
• 28 August Katrina
• Strong anomaly in Path AMSR-E
• 29 August Katrina
• Strong anomaly in Path AMSR-E
• Modest anomaly in Path

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Daily FTP OI Products

• AVHRR only
• Pathfinder (Jan '85 - Dec '05)
• Operational (Jan '06 - present)

• AVHRR AMSR-E
• Pathfinder (Jun '02 - Dec '05)
• Operational (Jan '06 - present)
• AMSR-E (Jun '02 - present)

• Test other data TMI, ATSR, MODIS