GRUAN and Lauder certification Greg Bodeker Co-chair of the Working Group on GRUAN Presented at the Lauder GRUAN Certification Function NIWA, Lauder, 10 March 2015

Overview First something about GCOS What brought GRUAN into existence? The goals of GRUAN GRUAN governance Who is the ‘they’? Why is GRUAN special? Site assessment and certification Certification of the Lauder site The way forward

GCOS – the Global Climate Observing System Joint undertaking of the World Meteorological Organization (WMO), the Intergovernmental Oceanographic Commission (IOC), the United Nations Environment Programme (UNEP) and the International Council for Science (ICSU). GCOS’s goals: provide comprehensive information on the total climate system. Consider the full range of physical, chemical and biological properties of the system. Consider all atmospheric, oceanic, hydrological, cryospheric and terrestrial processes. Includes both in situ and remote sensing components. Space-based components coordinated by the Committee on Earth Observation Satellites and the Coordination Group for Meteorological Satellites. Intended to meet the full range of national and international requirements for climate and climate-related observations.

GCOS Climate Monitoring Principles Impact of new systems or changes to existing systems should be assessed prior to implementation. Importance of collecting and archiving meta data. Quality and homogeneity of data should be regularly assessed. Operation of historically-uninterrupted stations and observing systems should be maintained. Good geographical coverage especially in regions where changes are occurring or are expected to occur. Long-term requirements should be specified to network designers, operators and instrument engineers at the outset of system design and implementation. Suitable period of overlap for new and old systems should be ensured to determine inter-system biases.

The problem From: Santer et al., Consistency of modelled and observed temperature trends in the tropical troposphere, International Journal of Climatology, DOI: /joc.1756, 2008.

What caused 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.

GCOS Reference Upper-Air Network (GCOS=Global Climate Observing System) Network for ground-based reference observations for climate in the free atmosphere in the frame of GCOS. The solution - GRUAN

The purpose of GRUAN 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.

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 …

The importance of monitoring for the long term The atmosphere has never been in steady state. Our knowledge of the system is incomplete.  We do not fully understand the impacts of what we may do (e.g. CFCs).  We do not fully understand how different aspects of the system may co-vary, particularly locally/regionally. Unless we monitor, analyze, reanalyze and question on a sustained basis there are risks. Therefore it is not sufficient solely to fund observations.  Failure of the discovery of the ozone hole due to automated screening of incoming data. As anthropogenic climate change effects increase the economic implications will increase.  Providing the best adaptation and mitigation advice is compromised if the observational basis is too uncertain

See for further information GRUAN Governance AOPC Task and analysis teams Guidance on research requirements Guidance on operational requirements Guidance on operational requirements Reporting Guidance WG-GRUAN Lead Center UNEPIOCICSUWMO WCRP GCOS SC CIMO/CBS/CAS/CCL Measurement sites

If they want it they should pay for it Who is the ‘they’? 1992: GCOS established. 1995: Long-Term Climate Monitoring by the Global Climate Observing System (GCOS): International Meeting of Experts, Asheville, North Carolina, U.S.A. 2004: Implementation plan for the Global Observing System for Climate in support of the UNFCCC → Key Action 12: Parties need to establish a high quality reference network of about 30 precision radiosonde stations and other collocated observations → Establish a GUAN-based reference network of high-quality, high-altitude (5 hPa) radiosondes. Endorsed by WMO. 2005: GRUAN: NOAA/GCOS Workshop to Define Climate Requirements for Upper-Air Observations 2007: GCOS-112 → GCOS Reference Upper-Air Network (GRUAN): Justification, requirements, siting and instrumentation options.

Who is the ‘they’? You are. NIWA and MetService Moving on: Why is GRUAN special?

Reference Observation A GRUAN reference observation: Is traceable to an SI unit or an accepted standard Is traceable to an SI unit or an accepted standard Provides a comprehensive uncertainty analysis Provides a comprehensive uncertainty analysis Maintains all raw data Maintains all raw data Includes complete meta data description Includes complete meta data description Is documented in accessible literature Is documented in accessible literature Is validated (e.g. by intercomparison or redundant observations) Is validated (e.g. by intercomparison or redundant observations)

Establishing reference quality Best estimate and uncertainty Traceable sensor calibration Uncertainty of input data Transparent processing algorithm Black box software Disregarded systematic effects Proprietary methods X X X

Site assessment and certification Quality of GRUAN sites assured through rigorous site assessment and certification process. GRUAN more than a collection of measurements made at individual sites → benefit accrues from homogeneity across the network. Shortfall in maintaining quality at one site reduces users’ confidence in measurements made across the network.

Certification of the Lauder site Minimum requirements for a GRUAN site: 1 weekly production radiosonde with the best technology currently available at the site; 1 monthly radiosonde capable of capturing the moisture signal in the upper troposphere and lower stratosphere and all other priority 1 variables to the best level possible with current technology, launched together with weekly radiosonde; At least twice daily observations of integrated precipitable water vapour. and should aspire to making: Regular 00 and 12 LST (as a preference over UTC) launches of a production radiosonde with the best technology currently available; Dual launches of sondes with highest quality humidity sensing capability in the upper troposphere and lower stratosphere; and Periodic intercomparisons of a large range of sonde types.

Certification of the Lauder site First, the Working Group on GRUAN thanks Richard Querel in particular, and the entire observations team at Lauder, for their excellence and professionalism in interacting with the Working Group over many months to bring Lauder through the GRUAN site assessment and certification process. Today we celebrate that achievement, hand over the certificate to Lauder, and recognize the Lauder site as a world-class upper-air observing station. The Working Group would also like to take this opportunity to thank Richard Querel for his science leadership role in GRUAN. The Working Group also thanks NIWA for its support of the Lauder site and for recognizing the value of GRUAN. Institutional support is a key aspect of site certification.

The way forward GRUAN requires close collaboration and cooperation between research and operational upper-air sites → requires close collaboration between NIWA and New Zealand MetService. GRUAN Certification of the Lauder RS92 radiosonde programme, and the acceptance of Lauder into GRUAN, is not the end of the road. It is the beginning of the road → new data streams will be coming online soon (certification of additional Lauder measurement programmes), Lauder will be audited by GRUAN in November 2018 (start preparing). Propagating Lauder’s skills and expertise to the GUAN and other upper-air stations → can NIWA/Lauder assist in establishing GRUAN sites in the Pacific? The world is looking to New Zealand to provide an example of how GRUAN should function → provide a good example.