The Global Oceanographic Data Archaeology and Rescue Project

Introduction.

Recognition of the importance of the world ocean as part of the earth's climate system has resulted in a demand for historical ocean profile and biological databases. To study this role, and to develop climate forecast capabilities, scientists need the most complete databases of historical and modern oceanographic data possible.
These databases, and scientific products based on these databases, are the infrastructure for much ocean and climate research. For example, the data are used to verify simulations of earth's climate system and to identify interannual-to-decadal ocean variability. Operational forecast centers use historical data to evaluate the quality of synoptic data. The data also help in the management of marine resources such as fisheries. Most importantly these data have been responsible for scientific work showing that the world ocean has warmed during the past 50 years in an amount consistent with the ocean response expected due to the observed increase of greenhouse gases in the earth's atmosphere since the start of the Industrial Revolution.
Fortunately, much oceanographic data has been gathered over the past century. Use of these data poses significant problems, however. Many historical oceanographic data sets are not widely available because they exist only in manuscript form and are at risk of decay and damage. Projects to digitize these data have been incomplete. Also, some data in electronic form are not generally available and are also at risk of loss due to media decay.
This article describes projects initiated in the early 1990s to locate at-risk data sets and incorporate them into a global, comprehensive, integrated, scientifically quality-controlled ocean profile-plankton database with all data in one, uniform format in order to facilitate oceanographic and climate research.

A BRIEF HISTORY OF OCEAN DATA MANAGEMENT

The science of physical oceanography can be considered to have started around 1902 with the formation of the International Council for Exploration of the Sea (ICES). ICES started as a consortium of western European countries with an interest in understanding the fluctuation of fisheries of the northeast Atlantic. ICES coordinated and planned the work of oceanographic data collection. Less recognized is that ICES encouraged the international exchange of oceanographic data through a data publication series. As time progressed, oceanographic institutions established data archives. For example, in the United States the Woods Hole Oceanographic Institute and the Scripps Institute of Oceanography became archive centers for Mechanical Bathythermograph Temperature (MBT) profile data beginning in the 1940s. Handwritten and/or typed cards contained the data.
The World Data Center (WDC) system was established during the International Geophysical Year (IGY) in 1957-58 in order that scientific data gathered as part of the IGY be permanently archived and accessible internationally without restriction. The WDC System (see http://www.ngdc.noaa.gov/wdc/wdcmain.html) operates under the auspices of the International Council of Scientific Unions, a non-governmental organization of scientific unions.
During the 1960s countries began establishing formal national oceanographic data centers to archive ocean data and provide services. These centers were organized internationally under the auspices of the Intergovernmental Oceanographic Commission (IOC) of UNESCO to encourage the international exchange of oceanographic data and to support capacity transfer from developed to less-developed nations.
In 1993 the IOC initiated the Global Oceanographic Data Archaeology and Rescue (GODAR). This project is led by WDC for Oceanography-Silver Spring. Next we briefly document the history and progress of this and related projects.
GOALS OF THE GODAR PROJECT.For the GODAR project, digitization of data now in manuscript and/or analog form is the highest priority. Other important tasks are:

1. the rescue of electronic data that might suffer media decay or neglect; ensuring that all oceanographic data available for international exchange are archived at two or more international data centers in electronic form;
2. preparation of catalogues (inventories) of data now available only in manuscript form or otherwise not available to the international scientific community;
3. performing quality control on all data and making all data available via the internet and media such as CD-ROMs.

IMPLEMENTATION.

The GODAR project focuses on physical, chemical, and plankton oceanographic data. Initially, most data digitized, or otherwise rescued, have been physical parameters. Recently, the rescue of tide-gauge measured sea level data has become part of the GODAR project.
Six regional international meetings were held during the first several years of the GODAR project to survey the oceanographic data held internationally in both manuscript and electronic form. The first phase of GODAR was deemed a success by an international GODAR review meeting (IOC Workshop Report 178).
In 1994, the European Union started supporting two projects focused on the rescue and analysis of temperature and salinity profiles in the Mediterranean and Black Seas. These projects successively released the Mediterranean Ocean Data Base (MODB), and, with further quality checks, the MEDATLAS. The database and products have been published on CD-ROMs.
GODAR has created a special focus on countries bordering the western Pacific through "GODAR/WESTPAC," which has a special project office at the Japan Oceanographic Data Center (JODC). Japan itself, working through the Japan Oceanographic Data Center has been a leading contributor to the GODAR project

RESULTS OF THE GODAR PROJECT.

The global historical database of temperature data has increased by approximately 3 million profiles as a result of GODAR, and the GODAR workshops have identified on the order of another 1.5 million profiles that are in manuscript form. The scientific community now has access to a more comprehensive ocean profile database than previously thought possible. The cost for ship time alone to gather the data already rescued would be about $3 billion in today's economy, assuming a cost of $16,000. per day for a medium-sized U.S. research ship. Figure 1 shows the number of Ocean Station Data (OSD) casts reversing thermometer temperature profiles recovered as part of the GODAR project.
The global historical database of temperature data has increased by approximately 3 million profiles as a result of GODAR, and the GODAR workshops have identified on the order of another 1.5 million profiles that are in manuscript form. The scientific community now has access to a more comprehensive ocean profile database than previously thought possible. The cost for ship time alone to gather the data already rescued would be about $3 billion in today's economy, assuming a cost of $16,000. per day for a medium-sized U.S. research ship. Figure 1 shows the number of Ocean Station Data (OSD) casts reversing thermometer temperature profiles recovered as part of the GODAR project.
Data gathered as a result of the GODAR project have been made available on CD-ROM as well as the Internet. Specifically, the data are distributed as part of a database known as World Ocean Database (WOD).
WOD contains approximately 7.3 million vertical profiles of temperature, 2.0 million salinity profiles, over 106,000 plankton biomass observations, and over 700,000 taxonomic observations among other data. Figure 2 shows the growth of the number of vertical profiles of temperature and salinity available from NODC/WDC due to the GOADR and other projects

BUILDING A GLOBAL OCEAN PROFILE-PLANKTON DATABASE.

Many problems are encountered in developing a database with so many different sources and different types of measurements. Metadata (information about the data such as ship name) or the data itself is sometimes incorrect or absent. This makes the development of databases relatively labor-intensive even though the databases are relatively small in size (<20 Gb). This effort is justified by the effort it costs to make the original measurements and the scientific utility of these databases and products based on them. Oceanography is an observational science and it is not possible to replace historical data that have been lost. In this sense, historical measurements of the ocean are priceless.
Nonetheless, we often receive questions about the importance and utility of historical oceanographic profile data. To respond to such questions we present Fig. 3, which shows the history of scientific citations for some NODC/WDC ocean profile databases and products based on these databases. The number of citations makes very clear that ocean profile databases have had an enormous impact on scientific research during the past twenty years.

FUTURE WORK

Substantial amounts of oceanographic data that have been identified as part of the GODAR project still need to be digitized and or transferred to fresher media and incorporated into regional and global databases. Efforts will continue to digitize these data and makethem available in future databases