The important role of: continuity of observations and data products for IPCC. Critical role for GCOS and WCRP. Kevin Trenberth NCAR. Climate Observations. Process studies : atmosphere, ocean, land, cryosphere and their interactions Sustained observations : the climate record
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continuity of observations and data products for IPCC
Critical role for GCOS and WCRP
GRUAN, GPS RO,
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.
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.).
Available Global GEWEX+ Datasets
3 – 6 hrs
Daily SST (1 Jan 2007)
Reynolds and Chelton 2010 JC
Sea Level OHC
Palmer et al 2010
NASA Team 2
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.
CALIPSO (t > 0.1)
High Cloud Amount (July)
absolute values depend on
but distributions similar
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
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.
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
1973 – 77K Obs every 6hrs
1987 – 550K Obs every 6hrs
1979 – 325K Obs every 6hrs
2006 – 4.2M Obs every 6hrs
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!
Trenberth, 2008 WMO Bull
An Integrated Earth System Information System