Post on 29-Jan-2016
description
transcript
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 20061 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
1. SSTs for 20052. Daily SST OI
NOAA’s National Climatic Data CenterAsheville, NC
OAA Climate Observation Program 4th Annual System ReviewSilver Spring, Maryland | May 10-12, 2006
Richard W. Reynolds (NOAA, NCDC)
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 ~ 60°N
SST Anomalies
2
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
Zonal SST Anomalies
3
NOTE:
Tim
e
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 20°S and 80°N
Zonal SST Anomalies
4
NOTE:
Tim
e
Left: July - Sept '04
Right: July - Sept '05
Anomalies shaded
Isotherms: 26-28ºC
• SSTs needed for hurricane formation: roughly > 26.5ºC
• Areas above 28ºC larger in 2005 than 2004
– Warmer anomalies tend to lie in these areas in 2005
Monthly SST
5
NOTE:
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 20066 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
2. Daily SST OI
NOAA’s National Climatic Data CenterAsheville, NC
OAA Climate Observation Program 4th Annual System ReviewSilver Spring, Maryland | May 10-12, 2006
Richard W. Reynolds (NOAA, NCDC)Thomas M. Smith (NOAA, NCDC)Kenneth S. Casey (NOAA, NODC)
Dudley Chelton (Oregon State University)
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
on 0.25° grid
7
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 20068 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
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
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 20069 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
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
• 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
Jan 2003: Standard Deviation
Top: Pathfinder
Bottom: AMSR-E
10
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200611 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
Pathfinder Advantages: Lower bias variability; data delayed
Operational Advantages: Real-time data; 1981-84 data
Nighttime Zonal Bias: AVHRR - In Situ
AVHRRPathfinder
- In Situ
AVHRROperational
- In Situ
90N
90S
90S
90N'82 '05
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200612 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
Weekly & Daily OIDecember 1991
12
• 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
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200613 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
• 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
Weekly & Daily OIJanuary 1998
13
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200614 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
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
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200615 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
OI Anomalies with Bias CorrectionJanuary 1988: Along equator
Daily OI computed with EOT bias correction
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
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200616 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
Daily Bias Differences: 1 Jan '03 - 31 Dec '04
EOTs reduce biases; Some residuals remain
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200617 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
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
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200618 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
Ship-Buoy SST Zonal Biases
• 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 !!
Annual Ship - Buoy Bias
Tim
e
'94
'05
60°S 60°N
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200619 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
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
• 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
Daily OI SST Anomalies
EOT satellite bias correction
20
Left: Pathfinder AVHRR OI Right: Pathfinder AVHRR +
AMSR-E OI
NOAA Climate Obs 4th Annual ReviewNOAA Climate Obs 4th Annual Review
Silver Spring, MD May 10-12, 2006Silver Spring, MD May 10-12, 200621 NOAA’s National Climatic Data CenterNOAA’s National Climatic Data Center
Daily FTP OI Products• AVHRR only
– Pathfinder (Jan '85 - Dec '05)– Operational (Jan '06 - present)
Dec '05Jun '02 Present
Pathfinder OperationalAVHRR +AMSR-E
AVHRROnly
Pathfinder Operational
Dec '05Jan '85 Present
• AVHRR + AMSR-E – Pathfinder (Jun '02 - Dec '05)– Operational (Jan '06 - present)– AMSR-E (Jun '02 - present)
• Test other data: TMI, ATSR, MODIS…