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Solar and Space Physics: A Science for a Technological Society
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SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
the elements of that system. The typical behavior of geospace, on a variety of spatial and temporal scales,
is of interest to the research and applications community. Gradual changes in solar activity, solar wind,
EUV radiation, and Earth’s magnetic field each play a significant role in defining the longer-term variation
in the geospace environment. For instance, long-term changes in Earth’s magnetic field are occurring and
producing measurable changes in the ionosphere. From the solar irradiance perspective, the latest solar
minimum, from late 2007 to mid-2009, marks the lowest solar EUV fluxes (and heating rates) of the longest
duration in the past four solar cycles. This “super-minimum” produced unprecedented low temperatures
in the ionosphere and a contracted thermosphere that none of the current numerical models were able to
predict or reproduce. This low solar minimum was also accompanied by a weaker than normal interplanetary magnetic field, cosmic rays at record high levels, high tilt angle of the solar dipole magnetic field, and
low solar wind pressure. All of these solar surface, solar wind, and interplanetary parameters constitute a
change in the space climate and played an integral role in how the AIM system evolved and responded.
These differences also had important practical consequences for satellite operations, space debris/hazard
prediction, ionospheric forecasts, and airline operations.
8.3.5 International Programs
AIM science is global in nature. International cooperation is thus a key component of the AIMI panel’s
decadal plan. One of the more important entities for coordinating these international efforts is the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP). SCOSTEP currently sponsors the Climate and
Weather of the Sun-Earth System (CAWSES) program. CAWSES was initiated in 2004 as a 5-year program
and was extended into a second phase dubbed CAWSES-II covering the period 2008-2012. The CAWSES-II
program focuses on four science questions: (1) What are the solar influences on Earth’s climate? (2) How
will geospace respond to an altered climate? (3) How does short-term solar variability affect the geospace
environment? and (4) What is the geospace response to variable waves from the lower atmosphere?
A successful example of international collaboration in space benefiting AIM science is the COSMIC
(Constellation Observing System for Meteorology Ionosphere and Climate) project. While the project is
jointly sponsored by Taiwan and the United States, its scientific benefits extend to all nations. Since its
launch in 2006, the COSMIC mission has observed the tidal influence on total electron content (TEC) and
F-region ionosphere, wave-4 signatures in the topside ionosphere/plasmasphere, and a geographically fixed
(with the Weddell Sea) ionospheric anomaly, and it is demonstrating the complex structure in ionosphere
F-region density and peak altitude.
Contributions also come from serendipitous opportunities. One such example is that from international
geodesy programs. The German Challenging Minisatellite Payload (CHAMP) and NASA/German Gravity
Recovery and Climate Experiment (GRACE) missions led to improved estimates of the thermosphere mass
density and winds from the need to better model and understand Earth’s gravity field and its spatial and
temporal variability. These thermosphere measurements have led to several discoveries and new insights
into the AIM system, such as a neutral density cusp enhancement, an equatorial thermosphere anomaly,
tides in the upper thermosphere, and periodic expansion of the thermosphere gas associated with coronal
hole distributions on the Sun.
8.3.6 Current and Future Programs
Solving the compelling, remaining mysteries of AIM science requires a continued commitment to a
space, ground, and modeling effort. Current and future programs and interagency activities provide context
Solar and Space Physics: A Science for a Technological Society
162
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
the elements of that system. The typical behavior of geospace, on a variety of spatial and temporal scales,
is of interest to the research and applications community. Gradual changes in solar activity, solar wind,
EUV radiation, and Earth’s magnetic field each play a significant role in defining the longer-term variation
in the geospace environment. For instance, long-term changes in Earth’s magnetic field are occurring and
producing measurable changes in the ionosphere. From the solar irradiance perspective, the latest solar
minimum, from late 2007 to mid-2009, marks the lowest solar EUV fluxes (and heating rates) of the longest
duration in the past four solar cycles. This “super-minimum” produced unprecedented low temperatures
in the ionosphere and a contracted thermosphere that none of the current numerical models were able to
predict or reproduce. This low solar minimum was also accompanied by a weaker than normal interplanetary magnetic field, cosmic rays at record high levels, high tilt angle of the solar dipole magnetic field, and
low solar wind pressure. All of these solar surface, solar wind, and interplanetary parameters constitute a
change in the space climate and played an integral role in how the AIM system evolved and responded.
These differences also had important practical consequences for satellite operations, space debris/hazard
prediction, ionospheric forecasts, and airline operations.
8.3.5 International Programs
AIM science is global in nature. International cooperation is thus a key component of the AIMI panel’s
decadal plan. One of the more important entities for coordinating these international efforts is the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP). SCOSTEP currently sponsors the Climate and
Weather of the Sun-Earth System (CAWSES) program. CAWSES was initiated in 2004 as a 5-year program
and was extended into a second phase dubbed CAWSES-II covering the period 2008-2012. The CAWSES-II
program focuses on four science questions: (1) What are the solar influences on Earth’s climate? (2) How
will geospace respond to an altered climate? (3) How does short-term solar variability affect the geospace
environment? and (4) What is the geospace response to variable waves from the lower atmosphere?
A successful example of international collaboration in space benefiting AIM science is the COSMIC
(Constellation Observing System for Meteorology Ionosphere and Climate) project. While the project is
jointly sponsored by Taiwan and the United States, its scientific benefits extend to all nations. Since its
launch in 2006, the COSMIC mission has observed the tidal influence on total electron content (TEC) and
F-region ionosphere, wave-4 signatures in the topside ionosphere/plasmasphere, and a geographically fixed
(with the Weddell Sea) ionospheric anomaly, and it is demonstrating the complex structure in ionosphere
F-region density and peak altitude.
Contributions also come from serendipitous opportunities. One such example is that from international
geodesy programs. The German Challenging Minisatellite Payload (CHAMP) and NASA/German Gravity
Recovery and Climate Experiment (GRACE) missions led to improved estimates of the thermosphere mass
density and winds from the need to better model and understand Earth’s gravity field and its spatial and
temporal variability. These thermosphere measurements have led to several discoveries and new insights
into the AIM system, such as a neutral density cusp enhancement, an equatorial thermosphere anomaly,
tides in the upper thermosphere, and periodic expansion of the thermosphere gas associated with coronal
hole distributions on the Sun.
8.3.6 Current and Future Programs
Solving the compelling, remaining mysteries of AIM science requires a continued commitment to a
space, ground, and modeling effort. Current and future programs and interagency activities provide context