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IQuOD Project Proposal

IQuOD Information Stream. I nternational Qu ality-controlled O cean D atabase. Tail for positive depth error is much bigger. Gaussian. Data User. Global Data Assembly Center. AOML. Automatic Quality Control Flags Applied. Data Provider.

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IQuOD Project Proposal

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  1. IQuOD Information Stream International Quality-controlled Ocean Database Tail for positive depth error is much bigger Gaussian Data User Global Data Assembly Center AOML Automatic Quality Control Flags Applied Data Provider A globally-coordinated effort to ‘clean up’ the ocean temperature profile database UK MET OFFICE & BAS SHIRSHOV INSTITUTE UNIVERSITY OF HAMBURG MRI, MIRC, JODC & TOHOKU UNIVERSITY IFREMER ISDM WHOI Manual Quality Control Performed Data and quality information Tim Boyer (GDAC leader) US National Oceanographic Data Center (on behalf of the CLIVAR/GSOP workshop team and international partners) SCRIPPS INCOIS & NIO USNODC Expert Center Expert Center Expert Center MNODC Josh Willis and Ann Thresher CSIRO, ACE CRCIMOS & BOM UFBA SHN • IQuOD Project Proposal • To produce and make publically available, the highest-quality standard possible historical subsurface ocean temperature (salinity) global database, along with the most complete metadata and formal error measurements. • To be achieved through global coordination and support. QC Problems (XBT data) Credit: Josh Willis (??) Ocean temperature/salinity data are essential to the understanding of variability and change in the Earth's energy/water cycle, and to discriminate between natural and anthropogenic drivers, particularly now in the context of climate change. The historical archive contains a large fraction of biased, duplicated and substandard quality data. So, efforts to analyse past ocean change and variability can be confounded, as can be the use of ocean data assimilation systems. Despite great effort by many groups in rescuing original profiles and metadata, refining quality, and reducing instrumental biases, there is no internationally sanctioned “climate-standard” ocean profile dataset. Presently, a number of institutions perform various levels of quality control, redoing the same job over many times in slightly different ways. In addition, no single group has the expertise and resources to do the complete quality control (QC ) job. International cooperation is required. With that in mind, attendees of a recent CLIVAR/GSOP workshop and interested parties from across the globe are formulating a coordinated approach to quality control ocean temperature (>13 million profiles) and salinity (in the near future) observations. The aim is to maximize the availability and consistency of these valuable and irreplaceable historical ocean subsurface data and to include proper characterization of uncertainty. Missing XBT metadata & bias corrections Source: Abraham et al. (2013, Rev. Geophys.) 1. Global Data Assembly Center The World Ocean Database (WOD) ideal starting database ( >18,000 datasets consolidated in one format) Huge QC challenge due to numerous sources/instrument (accuracies/biases) contribution over the years. First IQuOD phase is to focus on the period pre-1990. Coordinated QC efforts such as Argo will be used and their QC decisions heeded. WOD will also be the reassembly point, storing and posting final data and QC flags for IQuOD public dissemination. Number of profiles 2. Automatic Quality Control An agreed upon standard set of automated QC procedures will be developed to be quickly applied to any temperature profile type (currently groups are applying their automatic procedures to test datasets of known quality for comparison and assessment).. Automatic QC will identify the portion of profiles that need additional manual expert review. In the case of current WOD QC, this is ~7.5% of the temp. profiles (in the case of QuOTA, ~32%, Gronell et al. 2008) • A Global Data Assembly Center to both supply data to the IQUOD system and quickly and easily disseminate results. • A standardized internationally agreed upon set of automatic quality control for in situ ocean profile data. • A network of centers of excellence with specialized local knowledge in specific temperature profile data and the ability to produce high-quality reliable data sets. • A uniform quality controlled baseline historical temperature profile database with uncertainty estimates for oceanographic and climate studies. 3. Manual Quality Control Each suspect temperature profile will be examined and final QC decisions made. Centers of expertise will be designated based on institutional knowledge of the temperature structure of geographic regions, familiarity with instrumentation and QC challenges of historical observational periods (e.g., wire angle depth errors in bottle casts pre-World War II). Centers of expertise will communicate and compare QC decisions to reach an equilibrium between standardization and specialized knowledge. Tools similar to Mquest (Gronell et al. 2008) will be shared to facilitate manual QC. More details: http://www.clivar.org/organization/gsop/activities/clivar-gsop-coordinated-quality-control-global-subsurface-ocean-climate

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