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EXTENDED SUMMARY 17 SPACE WEATHER INFRASTRUCTURE Space weather services in the United States are provided primarily by NOAAâs SWPC and the U.S. Air Forceâs (USAFâs) Weather Agency (AFWA), which work in close partnership to address the needs of their civilian and military user communities, respectively. The SWPC draws on a variety of data sources, both space- and ground-based, to provide forecasts, watches, warnings, alerts, and summaries as well as operational space weather products to civilian and commercial users. Its primary sources of information about solar activity, upstream solar wind conditions, and the geospace environment are NASAâs Advanced Composition Explorer (ACE), NOAAâs GOES and POES satellites, magnetometers, and the USAFâs solar observing net- works. Secondary sources include SOHO and STEREO as well as a number of ground-based facilities. Despite a small and unstable budget (roughly $5 million to $6 million U.S. dollars annually) that limits capabilities, the SWPC has experienced a steady growth in customer base, even during the solar minimum years when disturbance activity is lower (Figure 8). The focus of the USAFâs space weather effort is on providing situational knowledge of the real-time space weather environment and assessments of the impacts AT SWPC weather on dif- EACH MONTH of space ferent Department of Defense (DOD) missions. The Air â¢ 400,000 Unique Customers Force uses NOAA data combined with â¢ 50,000,000 File Transfers (DMSP), the data from its own assets such as the Defense Meteorological Satellites Program â¢ 120 Countries Represented by Users â¢ 67,500,000 Web Hits â¢ 0.3 TBytes of Data Downloaded Impact Area Customer (examples) Action (examples) Cost (examples) Spacecraft â¢ Lockheed Martin â¢ Postpone launch â¢ Loss of spacecraft ~$500M (Individual systems to complete â¢ Orbital â¢ In orbit - Reboot systems â¢ Commercial loss exceeds $1B spacecraft failure; â¢ Boeing â¢ Turn off/safe instruments â¢ Worst case storm - $100B communications and radiation â¢ Space Systems Loral and/or spacecraft effects) â¢ NASA, DoD Electric Power â¢ U.S. Nuclear Regulatory Commission â¢ Adjust/reduce system load â¢ Estimated loss ~$400M from (Equipment damage to electrical â¢ N. America Electric Reliability Corp. â¢ Disconnect components unexpected geomagnetic storms grid failure and blackout â¢ Allegheny Power â¢ Postpone maintenance â¢ $3-6B loss in GDP (blackout) conditions) â¢ New York Power Authority Airlines (Communications) â¢ United Airlines â¢ Divert polar flights â¢ Cost ~ $100k per diverted flight (Loss of flight HF radio â¢ Lufthansa â¢ Change flight plans communications) â¢ $10-50k for re-routes â¢ Continental Airlines â¢ Change altitude (Radiation dose to crew and â¢ Korean Airlines â¢ Select alternate â¢ Health risks passengers) â¢ NavCanada (Air Traffic Control) communications Surveying and Navigation â¢ FAA-WAAS â¢ Postpone activities â¢ From $50k to $1M daily for single (Use of magnetic field or GPS â¢ Dept. of Transportation â¢ Redo survey company could be impacted) â¢ BP Alaska and Schlumberger â¢ Use backup systems 4.8 Murtagh.eps Figure 8. Examples of impact areas and customers for space weather data provided by the Space Weather Pre- diction Center (SWPC). More than 6500 unique customers subscribe to the SWPCâs product subscription service. Many data files and products are also available on an anonymous FTP server. Selected products are also distributed on the NOAA/National Weather Service dedicated broadcast systems. More than 50 million files are transferred from the SWPC web page each month. More than 500,000 files are created monthly with near-real-time data for 176 different products serving more than 400,000 unique customers every month in more than 120 countries. (Image courtesy of William Murtagh, NOAA Space Weather Prediction Center.)
18 EXTENDED SUMMARY Communications/Navigation Outage Forecasting System, the Solar Electro-Optical Network, the Digital Ionospheric Sounding System, and the GPS network (Figure 9). NASA is the third major element in the nationâs space weather infrastructure. Although NASAâs role is scientific rather than operational, NASA science missions such as ACE provide critical space weather information, and NASAâs Living with a Star program targets research and technologies that are relevant to operations. NASA-developed products that are candidates for eventual transfer from research to operations include physics-based space weather models that can be transitioned into operational tools for forecasting and situational awareness and sensor technology. NOAA, NASA, and the Air Force are all involved in the National Polar Orbiting Environmen- tal Satellite System (NPOESS), the joint civilian-military successor to the DMSP. Among its other objectives, NPOESS was intended to take over the DMSPâs space weather monitoring function. However, in 2006, because of large and increasing cost overruns, the NPOESS program under- went a dramatic restructuring. (Even before these changes, compromises had been made with regard to some of the desired space environmental measurements.) The restructuring eliminated sensors and reduced the size of the on-orbit constellation from three spacecraft to two, resulting in a system that will have less capability to make critical measurements of the space environ- ment than is currently available. The system is planned to last through 2024-2026, with the first NPOESS spacecraft to be launched 2013. Space-Based Example Mission Observing Forecasting Measurement Space Weather Parameter Supported Capability Capability (Threshold SSA) (Objective SSA) 1 DMSP/SES* Ionospheric Electrons (60%) 1, 2, 7 Geolocation 2 ACE/SOHO FO 3 GOES Ionospheric Disturbances (60%) 1, 2, 7 Communications 4 GPS Energetic Particles (90%) 1, 2, 3, 4, 5, 6, 7 Satellite Operations 5 DSP 6 NPOESS Radiation & Disturbances (75%) 1, 2, 3, 4, 5, 6, 7 Space Tracking 7 C/NOFS Ionospheric Disturbances (60%) 1, 2, 7 Navigation Good ( >75%) Moderate (50-75%) Marginal (25-50%) Little or None (0-25%) Ground-Based Example Mission Observing Forecasting Measurement Space Weather Parameter Supported Capability Capability (Threshold SSA) (Objective SSA) 1 SOON/ISOON 2 RSTN/RSTN II Ionospheric Electrons (60%) 1, 2, 3, 4, 5, 6 Geolocation 3 NEXION Ionospheric Disturbances (60%) 1, 2, 3, 4, 5, 6 Communications 4 TEC 5 SCINDA Energetic Particles (25%) 1, 2, 6 Satellite Operations 6 Geomag Radiation & Disturbances (40%) 1, 2, 3, 4, 5, 6 Space Tracking Ionospheric Disturbances (50%) 1, 2, 3, 4, 5, 6 Navigation *SES â Space Environment Sensors as payload on other satellites Figure 9. Sources and types of space weather data needed to support representative military mission areas. Color coding indicates the Air Force Weather Agencyâs current capability level. (Image courtesy of Herbert Keyser, U.S. 4.4 Keyser.eps Air Force.)
EXTENDED SUMMARY 19 In addition to NASA, NOAA, and the DOD, several other federal agencies (e.g., the National Science Foundation, the Department of Energy) are involved to varying degrees in the nationâs space weather effort, which is coordinated through the National Space Weather Program under the auspices of the Office of the Federal Coordinator for Meteorology. Other key elements of the nationâs space weather infrastructure are the solar and space physics research community and the emerging commercial space weather businesses. Of particular importance are the efforts of these sectors in the area of model development. Space Weather Forecasting: Capabilities and Limitations One of the important functions of a nationâs space weather infrastructure is to provide reli- able long-term forecasts, although the importance of forecasts varies according to industry. With long-term (1- to 3-day) forecasts and minimal false alarms, the various user communities can take actions to mitigate the effects of impending solar disturbances and to minimize their economic impact. Currently, NOAAâs SWPC can make probability forecasts of space weather events with varying degrees of success (Figure 10, top). For example, the SWPC can, with moderate confidence, predict 1 to 3 days in advance the probability of occurrence of a geomagnetic storm or an X-class flare, whereas its capability to provide even short-term (less than 1 day) or long-term forecasts of ionospheric disturbancesâinformation important for GPS usersâis poor. The SWPC has identified a number of critical steps needed to improve its forecasting capability, enabling it, for example, to provide high-confidence long-term and short-term forecasts of geomagnetic storms and ionospheric disturbances (Figure 10, bottom). These steps include securing an operational solar wind monitor at L1; transitioning research models (e.g., of coronal mass ejection propagation, the geospace radiation environment, and the coupled magnetosphere-ionosphere-atmosphere system) into operations; and developing precision GPS forecast and correction tools (Box 2). The requirement for a solar wind monitor at L1 is particularly important because ACE, the SWPCâs sole source of real-time solar wind and interplanetary magnetic field data, is well beyond its planned operational life, and provisions to replace it have not been made. Positioned 1.5 million kilometers upstream from Earth, ACE provides a critical ~45 minutes of advanced warning before a CME strikes Earth. Recognizing the importance of an upstream monitor, Congress mandated in the 2008 NASA Authorization Act that the Office of Science and Technology Policy âdevelop a plan for sustaining space-based measurements of solar wind from the L-1 Lagrangian point in space and for the dissemination of the data for operational purposes.â The plan is to be developed in consultation âwith NASA, NOAA, and other Federal agencies, and with industry.â Although the SWPC does not classify SOHO as a primary data source, it relies heavily on SOHO coronographic observations to predict the properties and trajectories of CMEs responsible for large geomagnetic storms. Space Weather Models Successfully forecasting space weather requires the development of a suite of models cover- ing the various domains of the space environment, from the solar corona to Earthâs ionosphere and thermosphere. An area of particular interest is the implementation for operational use of
20 EXTENDED SUMMARY Long-Term Forecast (1-3 days) Short-Term Forecasts and Warnings Now-casts and Alerts (<1 day) M-flare and X-flare probabilities M-flare and X-flare probabilities X-ray flux â global and regional Energetic Particle Environment (protons and Solar energetic particle probabilities Solar energetic particle probabilities electrons) â global and regional Geomagnetic storm probabilities â global Geomagnetic storm probabilities Geomagnetic activity â global and regional and regional Ionospheric disturbances (TEC, Ionospheric disturbance probabilities â Ionospheric disturbance probabilities irregularities, HF propagation) â global and global and regional regional Solar irradiance flux levels (EUV and 10.7 Solar irradiance (EUV and f10.7) â global cm) (1-7 days for f10.7) Short-Term Forecasts and Warnings Long-Term Forecast (1-3 days) 6.1 Bogdan.eps (<1 day) Now-casts and Alerts M-flare and X-flare probabilities M-flare and X-flare X-ray flux â global and regional Energetic Particle Environment (protons and Solar energetic particle probabilities Solar energetic particles electrons) â global and regional Geomagnetic storm probabilities Geomagnetic storms â global and regional Geomagnetic activity â global and regional Ionospheric disturbances (TEC, Ionospheric disturbances â global and Ionospheric disturbance probabilities irregularities, HF propagation) â global and regional regional Solar irradiance flux levels (EUV and 10.7 Solar irradiance (EUV and f10.7) â global cm) (1-7 days for f10.7) Figure 10. Top:â Capability levels of NOAAâs Space Weather Prediction Center in FY 2008. Bottom:â Potential ca- 6.2 Bogdan.eps pability levels in FY 2014, assuming adequate funding to support the developments listed in Box 2. Green, satis- factory; yellow, less than satisfactory; red, poor. (Image courtesy of Thomas J. Bogdan, Space Weather Prediction Center, NOAA.)
EXTENDED SUMMARY 21 Box 2 Future Developments Identified by the Space Weather Prediction Center as Needed to Improve Its Forecasting and Prediction Capability â¢ Secure an operational L1 solar wind monitor. â¢ Transition a numerical coronal mass ejection/solar wind model into operations. â¢ Secure backup capability for GOES-10 XRS (X Ray Spectrometer) data stream. â¢ omplete compliance measures necessary for the Space Weather Prediction Center to become a C partner in the National Climate Service to help guide future solar observations, research, modeling, and forecast development activities. â¢ Transition the whole-atmosphere model into operations. â¢ Develop forecast capabilities based on STEREO data streams. â¢ Revamp the concept of operations of the Space Weather Forecast Office. â¢ Transition a coupled magnetosphere/whole-atmosphere model into operations. â¢ Develop precision Global Positioning System forecast and correction tools. â¢ Develop operational radiation environment models. physics-based models, which can provide more accurate, longer-lead-time predictions of severe space weather conditions. In addition to physics-based forecast models, there is also a need for improved climatological models of Earthâs radiation environment (Figure 11). As noted earlier (p. 5), radiation belt climatology models are of special importance to the spacecraft industry. Models currently in use at the SWPC include the U.S. Total Electron Content model, which estimates the delays in GPS signals due to the changes in the electron content of the ionospheric path between the GPS satellite and the receiver, and the Wang-Sheeley-Arge model, which pre- dicts solar wind speed and the polarity of the interplanetary magnetic field at Earth. These are two important quantities for determining the severity of geomagnetic disturbances caused by solar wind and CME events. Among the models implemented by AFWA are the Global Assimilation of Ionospheric Measurements (GAIM) model, which assimilates data from a variety of space- and ground-based sources to specify the ionospheric environment, and the Hakamada-Akasofu-Fry (HAF) solar wind model. The Space Weather Modeling System currently under development by the DOD will couple the HAF model with the physics-based ionospheric model within the GAIM model, enabling multiday forecasts of the ionospheric environment and its response to solar wind forcing. To facilitate the transition of physics-based research models to operations, the multiagency Community Coordinated Modeling Center (CCMC) was established in the late 1990s. The CCMC tests and validates advanced space weather models developed by the research community and evaluates their usefulness for operations. The models hosted by the CCMC are available for use by the wider solar and space physics community.