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Transcript of 4 th WCRP Observations and Assimilation Panel Meeting Hamburg, Germany, March 29-31, 2010 1...
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20101
GCOS/WCRPWorking Group on
Observational Data SetsFor Reanalysis
Vose et al.
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20102
4 Terms of Reference
• Review data center holdings worldwide
• Develop a plan for integrated data sets
• Oversee progress of Implementing Centers
• Report regularly to AOPC and WOAP
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20103
• The Working Group has …– Assembled surface and upper air data set inventories– Augmented existing data sets– Developed plans for improving specific data sets– Focused on upcoming reanalyses– Served as a catalyst (e.g., NCDC wouldn’t have done…)
• The Working Group has not …– Denoted “official” Implementing Centers (loose confederation
has generated products thus far)– Held many meetings (one in Tokyo; e-mail and phone calls
otherwise; Trenberth encourages proposal for another)
Generalities
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20104
Dataset Activities
• 20th Century Reanalysis (C20R)– International Surface Pressure Databank (ISPD)– International Comprehensive Ocean Atmosphere Dataset– International Best Track Archive for Climate Stewardship
• Other data set activities (for ECMWF, etc.)– C20R datasets listed above– Integrated Global Radiosonde Archive (IGRA)– Satellite products (Bates, Zou, etc. encourage me to credit
these activities to the working group, but that’s a stretch; still, the data sets do benefit reanalyses…)
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20105
C20R Support
~0500 UTC Jan. 22, 1918 (ISPD)
~0000 UTC Jan. 22, 1918 (C20R)
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20106
Surface Pressure: ISPD 2.2.4
• GCOS/AOPC/OOPC Surface Pressure Working Group
• Identify, retrieve, digitize, merge, QC• Some numbers:
– 33 data sources– 33,653 stations– 1.7 billion obs– 1768-2008
• V3 in late 2010
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20107
Marine Data: ICOADS 2.5
• Surface reports from ships, buoys, other platforms
• SST, pressure, humidity, etc.
• 1662-2007, with preliminary updates thereafter
• Many new historical sources digitized
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20108
• 1st central repository, world’s largest archive
• 14 source datasets (including all RSMCs)
• ~10,000 storms from 1840-present
Tropical Cyclones: IBTrACS 2.0
1848-2008
1907-2007
1945-2007
1945-2007 1949-
2007
1851-2007
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 20109
Other Dataset Activities
• Integrated Global Radiosonde Archive (IGRA)
• Satellite products– SSM/I and SSMIS (NCDC, CSU, NESDIS/STAR)– MSU/AMSU (NESDIS/STAR et al.)
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201010
Notables:- v1 done in 2005
- v2 underway
- 42 source datasets (vs. 11)
- All reformatted
- Merging in process (no eta)
Upper Air Data:Integrated Global Radiosonde Archive
(IGRA)
Variables:- pressure
- geopotential height
- temperature
- dew point depression
- wind direction/speed
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201012
SSM/I and SSMIS
• Extended/improved period of record (1987-present)
• Completed in 2010, freely available from NCDC
• Fundamental climate data record effort by CSU and NESDIS/STAR is ongoing
• High-quality but proprietary RSS product still available for purchase
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201013
NESDIS/STAR MSU/AMSU
• V2 SNO out• 1979-2009• TIROS-N to
NOAA-18, MetOp-A
• V1 used in CFSR, MERRA
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201014
Reviewing theTerms of Reference
-- Slides with “?” = more feedback, please --
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201015
Need Feedback On …
• CCl partnership• More data set development work• Radiosonde temperature metadata• Better BUFR capability• Web-based catalogue• Working Group meeting• Other suggestions
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201016
Term of Reference #1
• Review:– The holdings of data centres worldwide … for
observations suitable for use in reanalysis or in observational studies.
– The opportunities for enhancement of these holdings through data recovery, collection, and reprocessing.
• Thoughts:– Well intentioned but works better when driven by a
specific need (e.g., C20R).– Somewhat related to Met Office proposal to CCl on
International Analysis of Land Surface Air Temperature (hold comments until next slide)
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201017
Partnership with CCl?
• Participation in workshop on Creating Surface Temperature Datasets to Meet 21st Century Challenges (preferably with a broader mandate)
• Real-time monitoring of synoptic reports by the working group (information passed to CCl, which in turn can encourage more reporting by individual countries – helps future reanalyses)
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201018
Continue Other Review Efforts?
• Focus on upcoming surface-only reanalyses by ECMWF and NOAA– Implies surface pressure (ISPD) and other primary
surface elements (Integrated Surface Dataset)
• Maybe a little more on the radiosonde record (ERA-CLIM)– Implies more work on IGRA
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201019
Term of Reference #2
• Develop a plan for … data sets:– Merging of holdings … incorporating metadata …– Development … of standards, version control, software …– Identification … of an Implementing Centre … for data sets
…– Extension of data sets in close to real time …– Maintenance and publication of a catalogue … of data sets
…
• Thoughts:– We have developed data sets instead. This will continue.– Some radiosonde temperature metadata work is needed.– More work on standards is possible, but it’s tough.– The time has come for the data set “catalogue.”
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201020
• When there were breaks, how big they were, how certain
• Include both documented and inferred changes
• Also include observation minus background (MERRA, C20R…)
• Basically give the assimilation system more information
• Or even try to homogenize (recommendation from SDS workshop, Microwave group)
Sonde Temperature Metadata?
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201021
• Universal formats are useful• As are nice interfaces to those formats• Can manage both input data and
feedback• Tedious to develop• Diverging opinions within the working
group on this
Better BUFR Capability?
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201022
• “A compilation, updated regularly, would be a major service.”
• What there is, where it is, how to get it• WG members can volunteer what they
know, provide contacts• Keep our pulse on the latest and greatest
for each data set• Hosted at NCDC• Alternative to the “Implementing Centre”
Web-Based Catalogue?
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201023
Small, Focused Workshop
• Working group members and selected others
• Add-on to another meeting– 3rd ACRE workshop: Reanalysis and Applications and the
U.S. Reanalysis/IESA workshop in Baltimore, MD (Nov. 2010)
– But those two meetings take up 5 days already
• Funding may be available through WOAP• Key issues are how our activities relate to
and take advantage of current reanalyses• Again, feedback welcome
4th WCRP Observations and Assimilation Panel Meeting
Hamburg, Germany, March 29-31, 201024
Reanalyses Suitable for Characterizing Long-Term Trends: Are They Really
Achievable?P.W. Thorne and R.S. Vose
Reanalyses are, by a substantial margin, the most utilized climate data products, and they are applied in a myriad of different contexts. Despite their popularity, there are substantial concerns about their suitability for the monitoring of long-term climate trends. This has led to calls for a truly “climate quality” reanalysis that retains long-term trend fidelity. The authors contend that for such a reanalysis to be achieved, a substantial rethinking of the current strategy for producing reanalysis products is required. First, the problem must be defined clearly. Second, the methodology that is employed must be reconsidered so as to minimize potential nonclimatic artifacts and robustly ascertain the inevitable residual uncertainty. Finally, a set of validation data and metrics must be constructed that the community can use to compare and unambiguously assess the claims of climate quality. The purpose of this essay is very much to initiate discussions to this end rather than to prescribe solutions.
(To be published in BAMS, March 2010)