1. The GCOS Reference Upper Air Network (GRUAN): creating an Arctic/Antarctic mirror Greg Bodeker GRUAN co-chair Antarctica New Zealand Annual Science Conference 2012 4 October 2012 Christchurch, New Zealand Presentation available at http://www.bodekerscientific.com/presentations

2. First something about GRUAN From: Santer et al., Consistency of modelled and observed temperature trends in the tropical troposphere, International Journal of Climatology, DOI: 10.1002/joc.1756, 2008.

3. The problem Historical observations made primarily for operational monitoring purposes. Ubiquitous change - impacts very rarely adequately quantified for climate trend determination. Ambiguity in the rate and details of climatic changes. Significant impediment to understanding climate change and its causes.

4. The solution The GCOS Reference Upper Air Network (GRUAN) Network for ground- based reference observations for climate in the free atmosphere in the frame of GCOS Initially 15 stations, envisaged to be a network of 30-40 sites across the globe when GRUAN becomes fully operational. See www.gruan.org for more detail

5. GRUAN sites Currently no sites in South America, Africa or Antarctica. Only one south of 12.5°S. GRUAN Network Expansion Workshop held in June 2012, in Berlin.

6. GRUAN governance Notes 1.WCRP identifies scientific and research requirements for GRUAN. WMO identifies operational requirements. 2.Composition of WG- GRUAN determined by Chair of AOPC in consultation with WMO. Includes representative from each of CIMO, CBS, CAS and CCl. 3.WG-GRUAN reports to AOPC 4.GRUAN measurement sites are contributed by member countries of WMO. GCOS SC #3 Measurement Sites #4 Lead CentreTask and Analysis Teams WG-GRUAN #2 ICSU Guidance GRUAN Reporting Guidance WMO #1 IOCUNEP AOPC CIMO/CBS/CAS/CCl Reporting Guidance on specific issues Guidance on Operational Requirements for GRUAN (GRUAN & WIGOS Manual) WCRP #1 Guidance on Science/Research Requirements for GRUAN Reporting

7. The goals of GRUAN The purpose of GRUAN is to: Provide long-term high quality climate records;Provide long-term high quality climate records; Constrain and calibrate data from more spatially-comprehensive global observing systems (including satellites and current radiosonde networks); andConstrain and calibrate data from more spatially-comprehensive global observing systems (including satellites and current radiosonde networks); and Fully characterize the properties of the atmospheric column.Fully characterize the properties of the atmospheric column. Four key user groups of GRUAN data products are identified: The climate detection and attribution community.The climate detection and attribution community. The satellite community.The satellite community. The atmospheric process studies community.The atmospheric process studies community. The numerical weather prediction (NWP) community.The numerical weather prediction (NWP) community.

8. More about goals of GRUAN Multi-decade measurement programmes. Characterize observational biases. Robust, traceable estimates of measurement uncertainty. Ensure traceability through comprehensive meta-data collection and documentation. Ensure long-term stability by managing measurement system changes. Tie measurements to SI units or internationally accepted standards. Measure a large suite of co-related climate variables with deliberate measurement redundancy Priority 1: Temperature, pressure, water vapour Priority 2: Ozone, methane …

9. Establishing reference quality

10. Uncertainty, redundancy and consistency Understand the uncertainties: Analyze sources - identify, which sources of measurement uncertainty are systematic (calibration, radiation errors), and which are random (noise, production variability …). Document this. Synthesize best uncertainty estimate: Uncertainties for every data point, i.e. vertically resolved Use redundant observations: to manage change to maintain homogeneity of observations across network to continuously identify deficiencies

11. The GRUAN Lead Centre, Lindenberg Free University of Berlin AWI, Potsdam GRUAN LC, FUB and AWI all in the greater Berlin area Proposed GRUAN site, Ny Alesund (78.9 o N) Mirror Lauder GRUAN site University of Otago/Canterbury? Antarctica New Zealand/NZARI? Scott Base/Arrival Heights (77.9 o S)?

12. What’s to be gained? Can we establish this as a nucleus for atmospheric climate research in New Zealand? Between the Lead Centre, FUB and AWI, considerable momentum is building around the implementation of GRUAN. New Zealand stands to gain a lot by tapping into this growing centre of excellence. New Zealand already has close ties to the Lead Centre. I spend 20% of my time on GRUAN activities and visit the Lead Centre annually. We have close working ties with the Institute for Meteorology at FUB. I am a formal collaborator on the SHARP project. We have close working ties with AWI. Steady flow of DAAD funded PhD students and work experience students. Visiting academics. Markus Rex (AWI) has a working visit to Canterbury University and BS from mid-February to end of April next year. New Zealand playing a key role in the establishment of a state-of-the- art global climate monitoring network. Sharing of skills and expertise would be primarily a one way flow into New Zealand.