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Page 1: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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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

Page 2: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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Climate ObservationsClimate Observations

Page 3: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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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

Page 4: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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.

Page 5: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

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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.

Page 8: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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 (%)

Page 9: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

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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

Page 13: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

Page 14: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

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Global mean precipitation Global mean precipitation

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Page 17: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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Page 18: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

Page 19: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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.

Page 20: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

• 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

Page 21: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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.

Page 22: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

Page 23: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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

Page 25: 1 The important role of: continuity of observations and data products for IPCC Critical role for GCOS and WCRP Kevin Trenberth NCAR Kevin Trenberth NCAR.

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


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