Assessment of Earth Observations Data Harmonization

Abstract

Earth observations through satellites are the basis for integrated scientific assessments of global environmental change. Institutional arrangements to coordinate these efforts have recognized data harmonization as essential toward achieving this end. The goal of data harmonization is to achieve compatibility of data polices among the various satellite platforms and programs. This paper discusses the issue of harmonization and assesses the variables of concern to harmonization on a comparative basis through an examination of Earth observation satellite programs in the United States and Europe. INTRODUCTION The goal of global change research and monitoring programs is to provide scientific information about the Earth system. It is this information that allows for decision-makers to formulate policies directed at managing global environmental problems. Achieving a comprehensive understanding of the Earth system requires a large-scale collection of environmental data on the atmosphere, oceans, and biosphere. An essential part of this data collection effort is to provide global data sets of the Earth through satellite observations. The issue of harmonization of Earth observation (EO) data represents one of the major problems that global change scientists face to reach this end. Harmonization involves the scientific, technical, and political coordination of EO science missions. The realization of harmonization is complicated by the fact that there are a number of EO platforms that provide environmental data. According to the Committee on Earth Observation Satellites (CEOS), there are over sixty Earth observation satellite missions operating and approximately ninety missions planned within the next fifteen years that will produce terabytes of data. Given this plethora of EO missions and data, a key challenge for harmonization concerns the extent to which the different data policy interests of the numerous national space agencies and organizations, which provide the EO platforms and data, are compatible. Even though data policies are designed to promote the scientific utility of EO data, national political interests and organizational factors place unintentional barriers to this end. These barriers diminish the utilization of the data for scientific studies. Overcoming political and organizational barriers requires coherence among the different EO data policies. Despite the fact that there is no single international agency or multilateral legal regime to achieve data policy coherence, there is coordination to harmonize EO data at the international level, such as exemplified by the work of CEOS. This paper, first, addresses how the harmonization concept is viewed and interpreted by relevant international organizations and the U.S. The paper then proceeds to examine the political issues of harmonization related to data policies, which encompass the variables of data access, data preservation, data protection, and data standards. Following this discussion domestic and international variables that influence harmonization are analyzed. These variables are assessed on a comparative basis through an examination of Earth observation data polices in the U.S. and Europe. 54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law 29 September 3 October 2003, Bremen, Germany IAC-03-B.1.08 Copyright © 2003 by the author(s). Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Released to IAF/IAA/AIAA to publish in all forms. 2 HARMONIZATION CONCEPT Harmonization is recognized as essential towards achieving the integrated scientific assessments of the global environment by a number of international organizations, which include CEOS and the former International Earth Observing System (IEOS), global observation systems and strategies, such as Global Terrestrial Observing System (GTOS) and the Integrated Global Observing Strategy (IGOS), and by the U.S. The relevant views on harmonization of each of these actors are discussed below. Harmonization is either explicitly stated as a goal, particularly in the realm of data preservation, or implied from the common views that the actors hold with regard to variables that affect harmonization. Explicit Harmonization. CEOS explicitly states the need for harmonization of EO data in its formal Data Exchange Principles (DEPs) for global change research— “...criteria and priorities for data acquisition, archiving and purging should be harmonized.” The need for harmonization is further developed in CEOS DEPs that promote use of EO data— “...criteria and priorities for data acquisition, processing, distribution, preservation, archiving, and purging should be harmonized to take into account the needs of users for data...” These statements illustrate that CEOS views harmonization as a technical issue dealing with the goal of long-term preservation of EO data. Specifically, CEOS views harmonization as achieving coherence among the criteria for data acquisition and archiving. To implement this, the CEOS Working Group on Information Systems and Services (WGISS) functions as the ‘harmonization’ group for data generated by Earth observing satellites and other sources. This group deals with efforts for achieving Albeit the European Space Agency (ESA) is committed to the concept of harmonization, it should be noted that there are no explicit or even implied statements in ESA’s data policies that deal with harmonization. coherent data preservation and archiving systems, and for common data formats and standards. The view of IEOS on harmonization was similar to that of CEOS. IEOS, in its drafted