The important role of: continuity of observations and data products for IPCC
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The important role of: continuity of observations and data products for IPCC
Critical role for GCOS and WCRP
Kevin TrenberthNCAR
Kevin TrenberthNCAR
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Climate ObservationsClimate Observations
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WOAP: Key climate issues
Climate data records Continuity, continuity, continuity; The need for reprocessing and reanalysis of past data and coordination of these activities among agencies and variables; Includes evaluation and assessment or results Importance of calibration, accuracy, benchmarks, Space and in situ observations;
Reanalysis to produce global gridded
fields
WOAP: Key climate issues
Climate data records Continuity, continuity, continuity; The need for reprocessing and reanalysis of past data and coordination of these activities among agencies and variables; Includes evaluation and assessment or results Importance of calibration, accuracy, benchmarks, Space and in situ observations;
Reanalysis to produce global gridded
fields
GRUAN, GPS RO, CLARREO
World Climate Research ProgrammeWorld Climate Research Programme4
WOAP-1Reprocessing: assess variables for need and readiness, and commitments. Include in GEOSS.
5 Principles for Re-Processing Climate Data Records
For climate, the value of an observational record increases with time, provided that the record is continuous and homogeneous.
As datasets are used, characteristics of the data and problems are exposed, and often solutions to problems or algorithm improvements are proposed, especially for satellite measurements.
Accordingly, re-processing of the record should be an integral part of the process of creating a climate data record.
WOAP-1Reprocessing: assess variables for need and readiness, and commitments. Include in GEOSS.
5 Principles for Re-Processing Climate Data Records
For climate, the value of an observational record increases with time, provided that the record is continuous and homogeneous.
As datasets are used, characteristics of the data and problems are exposed, and often solutions to problems or algorithm improvements are proposed, especially for satellite measurements.
Accordingly, re-processing of the record should be an integral part of the process of creating a climate data record.
Parameter
Clouds
Water Vapor
TOA Radiation
Precipitation
SRF Radiation
Atmospheric Circulation
Evaporation
1979 1985 1990 1995 2000 2005 2010TIME
Available Global GEWEX+ DatasetsPentadDaily3 – 6 hrs
50 km
250 km
100 km
50 km
50 km
100 km
100 km
WCRP/GCOSWOAP workshop: ESRIN, Frascati 18-20 April 2011Evaluation of satellite climate datasetsidentification of best practices in evaluating and inter-comparing global climate datasets, especially where there is more than one data set for a given parameter (e.g., surface temperature, sea ice concentrations, etc.).
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Large disparities among different
analysesDaily SST (1 Jan 2007)
Reynolds and Chelton 2010 JC
Sea Level OHCPalmer et al 2010
OceanObs’09
Total sea ice area, 2007 and 2008
20072008
NASA TeamNASA Team 2SSM/I BootstrapAMSR BootstrapASICal/Val (York)BristolNorsex
Avg. of 8 algorithms& ±1 st. dev. range
No single algorithm
clearly superior
The largest factor for ice concentration/extent consistency is intercalibration of the products through transitions through different generations of satellite-borne sensors.
High Cloud Amount (July)
absolute values depend on
instrument sensitivity
& method,
but distributions similar
CALIPSOAIRS-LMD
ISCCP
PATMOS-x
MODIS-ST
MODIS-CE
(%)
CALIPSOCALIPSO ( > 0.1)
AIRS_LMD
ISCCPTOVS Path-B
HCA (%)
Trends in LH Flux?
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ReanalysisReanalysis1. Reanalysis is an essential part of climate
services, especially in monitoring, attribution and prediction
2. Major problems remain from the changing observing system
3. There is not a problem with lack of reanalyses, but: 1. lack of an end to end program with adequate
vetting and evaluation of products (and the funding for that), and
2. Reanalysis is all done in a research domain and not sustained, so that key personnel can be lost.
3. Lack of adequate vetting and diagnosis
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Reanalysis Horiz.Res Dates Vintage Status
NCEP/NCAR R1 T62 1948-present 1995 ongoing
NCEP-DOE R2 T62 1979-present 2001 ongoing
CFSR (NCEP) T382 1979-present 2009 thru 2009, ongoing
C20r (NOAA) T62 1875-2008 2009 Complete, in progress
ERA-40 T159 1957-2002 2004 done
ERA-Interim T255 1989-present 2009 ongoing
JRA-25 T106 1979-present 2006 ongoing
JRA-55 T319 1958-2012 2009 underway
MERRA (NASA) 0.5 1979-present 2009 thru 2010, ongoing
Current atmospheric reanalyses, with the horizontal resolution (latitude; T159 is equivalent to about 0.8 ), the starting and ending dates, the approximate vintage of the model and analysis system, and current status.
Atmospheric Reanalyses
NovNOAA-18
EOS AquaOct
F08
F15
SSM/I
Jul DecF10
Nov
DecF11
Dec
DecF13
MayF14
May
Dec Aug
Apr Jul
Apr Jun
Jul
GOES-08
GOES-10
GOES-12
TIROS-NDec Feb
Jul Apr OctNovNOAA-6
FebSep NOAA-7
May Jun Jul OctNOAA-8
Jan NovNOAA-9
NOAA-10Dec Sep
Nov Jan Sep Sep NOAA-11
JunSep NOAA-12
JanNOAA-14
SepNOAA-15
NovNOAA-16
JulNOAA-17
Dec
TOVS
ATOVS
EOS Aqua
GOESSounders
78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08
Satellite Data Streams assimilated
The Changing Observing System
1973 – 77K Obs every 6hrs
1979 – 325K Obs every 6hrs
1987 – 550K Obs every 6hrs
2006 – 4.2M Obs every 6hrs
1973 77k/6h 1987 550k
1979 324k 2006 4,220k
NWP Forecast skill scores continue to improve
Extratropical NH and SH forecasts: 12 month means plotted at last month. Updated from Simmons and Hollingsworth 2002 SH skill became comparable to NH after about 2002!
Reanalysis
Global mean precipitation Global mean precipitation
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World Climate Research ProgrammeWorld Climate Research Programme20
Future needs: Observations and Analysis
Future needs: Observations and Analysis
Observations: in situ and from space (that satisfy the climate observing principles);
A performance tracking system; Climate Data Records (CDRs) The ingest, archival, stewardship of data,
data management; Access to data Data (re)processing and analysis The analysis and reanalysis of the
observations and derivation of products, Data assimilation and model initialization
Observations: in situ and from space (that satisfy the climate observing principles);
A performance tracking system; Climate Data Records (CDRs) The ingest, archival, stewardship of data,
data management; Access to data Data (re)processing and analysis The analysis and reanalysis of the
observations and derivation of products, Data assimilation and model initialization
Future needs: ModelsFuture needs: Models Data assimilation and model initialization Better, more complete models Assessment of what has happened and why
(attribution) including likely impacts on human and eco-systems;
Prediction of near-term climate change over several decades: ensembles
Statistical models: applications Downscaling, regional information Responsiveness to decision makers and
users.
Data assimilation and model initialization Better, more complete models Assessment of what has happened and why
(attribution) including likely impacts on human and eco-systems;
Prediction of near-term climate change over several decades: ensembles
Statistical models: applications Downscaling, regional information Responsiveness to decision makers and
users.
• The coordinated collection, analysis and reanalysis of climate observations is required to describe the structure and variability of the climate system.
• Observations give the basis for evaluating and improving models, and models providing the framework and impetus for deciding what observations to take.
• Special efforts required to obtain, analyse and assimilate data from the new generation of environmental satellites.
• Enables the generation of descriptions of states of the coupled climate system consistent with all variables and the physical framework provided by models, both for prediction and for documenting the climate record.
Role of WCRP
Role of WCRP Advocate improved observations and analysis
suitable for climate (satisfying the GCOS Climate Monitoring Principles to ensure continuity of record). This especially includes those from space.
Data set development: evaluating observations and promoting global reprocessing and reanalysis. Develop new products and datasets, analytical and diagnostic techniques, high level derived products: for use in understanding and analyzing climate variability and change, and for evaluating models.
Mechanisms and modes of variability in climate anomalies; operational attribution, numerical experimentation in near real time to allow reliable statements to be made not only about what the state of the climate is, but also why it is the way it is and the mechanisms involved.
Role of WCRP
Data assimilation and analysis: initializing of coupled models for prediction.
• Provide advice on best datasets for various purposes (climatologies and time series) and their merits and limitations. (Error bars are greatly needed.)
• High priority needs are to have assessments of datasets for use in evaluating climate models, and specifically those used in the AR5 IPCC report that will participate in the CMIP5 activity
Role of WCRP
Help improve and promote sound data stewardship, including data archiving, management, and access. This includes making sure that climate-related data variables are reaching data archives, and that standards are set for archiving new types of data.
Help make data accessible and available e.g., through the internet. Promote shared efforts for data quality control.
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Climate Information SystemClimate Information System
Trenberth, 2008 WMO Bull
WCRPWCRP
Imperative: A climate information
system
Imperative: A climate information
system Observations: forcings, atmosphere, ocean, land
Analysis: comprehensive, integrated, products Assimilation: model based, initialization Attribution: understanding, causes Assessment: global, regions, impacts, planning Predictions: multiple time scales Decision Making: impacts, adaptation
Observations: forcings, atmosphere, ocean, land
Analysis: comprehensive, integrated, products Assimilation: model based, initialization Attribution: understanding, causes Assessment: global, regions, impacts, planning Predictions: multiple time scales Decision Making: impacts, adaptation
An Integrated Earth System Information SystemAn Integrated Earth System Information System