Data archaeology and rescue is about searching out historical data which are not in recognised archives and rescuing them by digitising manuscript and paper chart data and making them freely available. Long-term sea level data series are rare and the measurements unrepeatable.  

Over the last 20 years GLOSS has: 

  • encouraged countries to assess their holdings of historical data which could potentially be rescued 
  • explored tools/automated techniques for the digitization of archived tidal charts or mareograms 
  • investigated sources of funding  
  • proposed "Guidelines" for rescuing sea level data.  

Priority issues include: 

  • More data are needed to support accurate, real-time ocean hazard detection, forecast, warning and responses, including baseline data 
  • Gaining access to a large amount of existing data not currently shared 
  • Challenging biases. Current research has geographic biases (e.g., where data are collected, with gaps in the global south, for example) 
  • Incorporating citizen science data 

Data archaeology activities will help fill in the gaps in the global dataset, with records in the southern hemisphere being particularly valuable. Two such examples are: 

  • Hunter et al. used historical observations from a tide gauge at Port Arthur, Tasmania, to indicate an average rate of sea level rise from 1841 to 2002 (Hunter, J. et al. The sea level at Port Arthur, Tasmania, from 1841 to the present. Geophys Res Lett 2003;30:7.) 
  • Testut et al. used measurements taken from a tide staff on Saint Paul Island in the southern Indian Ocean to estimate a rate of relative sea level change from 1874 to 2009. (Testut, Laurent. et al. Sea level at Saint Paul Island, southern Indian Ocean, from 1874 to the present. J Geophys Res 2010 [(1978–2012) 115.C12].) 

In March 2020, GLOSS held an international Sea Level Data Archaeology Workshop which brought together experts concerned with sea level data rescue activities to explore the potential for a more sustained programmatic approach to cooperation at the international level. Follow the link to access the agenda, report and presentations.