The radio frequency spectrum is a limited resource with ever increasing demand from an expansive range of applicationsâ€"all the way from commercial, such as mobile phones, to scientific, such as hurricane monitoring from space. Since radio waves do not stop at national borders, international regulation is necessary to ensure effective use of the radio spectrum for all parties. Every 2 to 5 years, the International Telecommunication Union convenes a World Radiocommunication Conference (WRC) to review and revise the international radio regulations. This report provides guidance to U.S. spectrum managers and policymakers as they prepare for the WRC in 2019. While the resulting document is targeted primarily at U.S. agencies dealing with radio spectrum issues, other Administrations and foreign scientific users may find its recommendations useful in their own WRC planning.

The radio frequency spectrum is a limited resource for which there is an ever-increasing demand from an expansive range of applications - all the way from commercial, such as mobile phones, to scientific, such as hurricane monitoring from space. Since radio waves do not stop at national borders, international regulation is necessary to ensure effective use of the radio spectrum for all parties. Use of the radio spectrum is regulated internationally by the Radio Regulations (RR), an international treaty. The International Telecommunication Union (ITU) has as its mission the facilitation of the efficient and interference-free use of the radio spectrum. Every 2 to 5 years, the ITU convenes a World Radiocommunication Conference (WRC) to review and revise the international RR. Changes to the RR are formulated through proposals to the conference according to Agenda Items, which are agreed on at the previous WRC. At the request of the National Science Foundation and the National Aeronautics and Space Administration, this report provides guidance to U.S. spectrum managers and policymakers as they prepare for the 2023 WRC to protect the scientific exploration of Earth and the universe using the radio spectrum. This report identifies the 2023 agenda items of relevance to U.S. radio astronomers and Earth remote sensing researchers, along with proposed agenda items for the 2027 WRC.

The passive, receive-only Radio Astronomy Service (RAS) and the Earth Exploration-Satellite Service (EESS) provide otherwise impossible scientific observations of the Universe and Earth through the use of advanced receiver technology with extreme sensitivity and the employment of complex noise reduction algorithms. Even with such technology, RAS and EESS are quite adversely affected by what most active services would consider low noise levels. To ensure their ability to use the radio spectrum for scientific purposes, scientists must be party to the discussion in the lead-up to the World Radiocommunication Conference (WRC), which will next be held in January and February 2012 in Geneva, Switzerland. By request of the National Science Foundation and the National Aeronautics and Space Administration, the National Research Council was convened to provide guidance to the U.S. spectrum managers and policymakers as they prepare for the WRC in order to protect the scientific exploration of the Earth and Universe using the radio spectrum. While the resulting document is targeted at U.S. agencies, representatives of foreign governments and foreign scientific users will find its contents useful as they plan their own WRC positions.

The World Radiocommunication Conference (WRC) is a meeting of official delegations from over 140 nations and is organized by the International Telecommunication Union (ITU). Delegates meet every few years to negotiate proposals to changes in international radio spectrum regulations; changes that would be enforced by the ITU internationally if approved. Proposals are brought up during a WRC and then negotiated at the next WRC. The time in between each WRC allows for national governments to work internally and with their regional counterparts to develop a consensus position on each proposal. The consensus position can then be presented at the next WRC. Each proposal is referred to as an agenda item and agenda items are specific and propose narrow yet potentially substantial changes to the use of the spectrum that can have significant impact on its users. Most agenda items support the active use of the spectrum, so it is important for vulnerable, passive services to voice their concerns about potentially adverse effects on their operations. Two U.S. passive services, the passive Radio Astronomy Service (RAS) and the Earth Exploration-Satellite Service (EESS), provide scientific observations of the universe and Earth through the use of advanced receiver technology with extreme sensitivity and the employment of complex noise reduction algorithms. Even with such technology, RAS and EESS are seriously adversely affected by what most active services would consider extremely low noise levels. Views of the U.S. NAS and NAE on Agenda Items at Issue at the World Radiocommunication Conference 2015 present the NAS and NAE\'s views on agenda items that affect RAS and EESS. This report includes a list of each agenda item, how it affects the programs, and the committee\'s recommendations.

Following a series of natural disasters, including Hurricane Katrina, that revealed shortcomings in the nation's ability to effectively alert populations at risk, Congress passed the Warning, Alert, and Response Network (WARN) Act in 2006. Today, new technologies such as smart phones and social media platforms offer new ways to communicate with the public, and the information ecosystem is much broader, including additional official channels, such as government social media accounts, opt-in short message service (SMS)-based alerting systems, and reverse 911 systems; less official channels, such as main stream media outlets and weather applications on connected devices; and unofficial channels, such as first person reports via social media. Traditional media have also taken advantage of these new tools, including their own mobile applications to extend their reach of beyond broadcast radio, television, and cable. Furthermore, private companies have begun to take advantage of the large amounts of data about users they possess to detect events and provide alerts and warnings and other hazard-related information to their users. More than 60 years of research on the public response to alerts and warnings has yielded many insights about how people respond to information that they are at risk and the circumstances under which they are most likely to take appropriate protective action. Some, but not all, of these results have been used to inform the design and operation of alert and warning systems, and new insights continue to emerge. Emergency Alert and Warning Systems reviews the results of past research, considers new possibilities for realizing more effective alert and warning systems, explores how a more effective national alert and warning system might be created and some of the gaps in our present knowledge, and sets forth a research agenda to advance the nation's alert and warning capabilities.

Affecting technological systems at a global-scale, space weather can disrupt high-frequency radio signals, satellite-based communications, navigational satellite positioning and timing signals, spacecraft operations, and electric power delivery with cascading socioeconomic effects resulting from these disruptions. Space weather can also present an increased health risk for astronauts, as well as aviation flight crews and passengers on transpolar flights. In 2019, the National Academies was approached by the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the National Science Foundation to organize a workshop that would examine the operational and research infrastructure that supports the space weather enterprise, including an analysis of existing and potential future measurement gaps and opportunities for future enhancements. This request was subsequently modified to include two workshops, the first (Phase I) of which occurred in two parts on June 16-17 and September 9-11, 2020. The Phase II workshop occurred on April 11-14, 2022, with sessions on agency updates, research needs, data science, observational and modeling needs, and emerging architectures relevant to the space weather research community and with ties to operational needs. This publication summarizes the presentation and discussion of that workshop.