The important role of: continuity of observations and data products for IPCC

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

2. Climate Observations • Process studies: atmosphere, ocean, land, cryosphere and their interactions • Sustained observations: the climate record • Enhanced monitoring • Analysis, assimilation and data products • Data stewardship, data access, QC • JSC 2010: • Observations white paper

3. 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

4. WOAP-1 Reprocessing: 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.

5. WCRP/GCOS WOAP workshop: ESRIN, Frascati 18-20 April 2011 Evaluation of satellite climate datasets identification 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.). Pentad Available Global GEWEX+ Datasets Daily 3 – 6 hrs TIME 1979 1985 1990 1995 2000 2005 2010 Parameter Clouds WaterVapor 50 km Precipitation 250 km 100 km TOARadiation 100 km SRF Radiation 100 km Evaporation 50 km AtmosphericCirculation 50 km

6. Large disparities among different analyses Daily SST (1 Jan 2007) Reynolds and Chelton 2010 JC Sea Level OHC Palmer et al 2010 OceanObs’09

7. Total sea ice area, 2007 and 2008 NASA Team NASA Team 2 SSM/I Bootstrap AMSR Bootstrap ASI Cal/Val (York) Bristol Norsex Avg. of 8 algorithms & ±1 st. dev. range No single algorithm clearly superior 2007 2008 The largest factor for ice concentration/extent consistency is intercalibration of the products through transitions through different generations of satellite-borne sensors.

8. ISCCP MODIS-ST HCA (%) PATMOS-x MODIS-CE ISCCP TOVS Path-B CALIPSO CALIPSO (t > 0.1) AIRS_LMD CALIPSO AIRS-LMD (%) High Cloud Amount (July) absolute values depend on instrument sensitivity & method, but distributions similar

9. Trends in LH Flux?

10. Reanalysis Reanalysis is an essential part of climate services, especially in monitoring, attribution and prediction Major problems remain from the changing observing system There is not a problem with lack of reanalyses, but:  lack of an end to end program with adequate vetting and evaluation of products (and the funding for that), and Reanalysis is all done in a research domain and not sustained, so that key personnel can be lost.  Lack of adequate vetting and diagnosis

11. Atmospheric Reanalyses Current atmosphericreanalyses, 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.

12. Satellite Data Streams assimilated TIROS-N Dec Feb NOAA-6 TOVS Jul Apr Nov Oct NOAA-7 Sep Feb NOAA-8 May Jun Jul Oct NOAA-9 Jan Nov NOAA-10 Dec Sep NOAA-11 Nov Jan Sep Sep NOAA-12 Sep Jun NOAA-14 Jan Dec NOAA-15 Sep ATOVS NOAA-16 Nov NOAA-17 Jul NOAA-18 Nov EOS Aqua EOS Aqua Oct GOES-08 GOES Sounders Apr Jul GOES-10 Apr Jun F08 GOES-12 Jul Jul Dec F10 SSM/I Dec Nov F11 Dec Dec F13 May F14 May Dec Aug F15 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

13. The Changing Observing System • 1973 77k/6h 1987 550k • 1979 324k 2006 4,220k 1973 – 77K Obs every 6hrs 1987 – 550K Obs every 6hrs 1979 – 325K Obs every 6hrs 2006 – 4.2M Obs every 6hrs

14. NWP Forecast skill scores continue to improve Reanalysis 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!

15. Global mean precipitation

18. 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

19. Future 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.

20. Role of WCRP • 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.

21. 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.

22. 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

23. 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.

24. WCRP Climate Information System Trenberth, 2008 WMO Bull

25. 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 An Integrated Earth System Information System