2002 SPACE SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| GETTING TO THE SORCE OF CLIMATE CHANGE
| G02-079A | 2/14/03 | 00:26:03 | The Earth presents scientists with a curious puzzle: the phenomenal interconnectedness of each aspect of our world leads to misconceptions and incomplete notions regarding climate change. How much is due to man's activity versus naturally occurring? What role does the Sun play in our climate and how do changes within the Sun affect us? The SOlar Radiation and Climate Experiment (SORCE) seeks to find one large piece of the puzzle by continuing to track and observe the amount and destination of solar radiation entering into our system. SORCE will also be going a long way to give some indication of change within our great star over its 11-year cycle as well as more rapid changes affecting our atmosphere.
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TAPE CONTENTS: |
| ITEM (1): Reporter Package
- The Sun... The source of life on Earth. But the Sun's output changeseven on a daily basis leaving questions about its short and long-term influence on Earth.
Enter NASA's Solar Radiation and Climate Experiment, or SORCE.
... If you don't measure the Sun, ... and you carry on making all the other measurements, there's always the question of what you're seeing, is it really true? Is it really what's happening with climate or could it be the Sun that is also playing a role? (GARY ROTTMAN)
Among its main goals SORCE will monitor the Sun's radiative output and measure how that output changes. From a vantage point just 400 miles above the surface, the satellite will also gauge Earth's absorption and reflection of the various wavelengths of light entering our atmosphere.
SORCE, for the first time will tell us how much of the energy varying in the solar cycle is in the ultraviolet versus the visible, versus the near infrared. Visible goes into the ocean and near infrared goes into the atmosphere and that relative amount is what controls convection, cloud formation, and so on. (BOB CAHALAN)
Of the solar energy reaching the top of the Earth's atmosphere, roughly 30 percent is reflected back into space. About 20 percent gets absorbed by our atmosphere - leaving nearly half of the energy to be absorbed by the land and oceans. A delicate balance exists between energy absorption and reflection. This radiation balance allows Earth to lose heat at roughly the same rate it gains from the Sun.
And the Sun is changing. Every eleven years, the Sun reaches a maximum state of activity marked by as many as 200 sunspots per month and a minimum of a few dozen. While significant for the study of space weather, it's the sunspot's warmer counterpart-- white regions called faculae--that produce the bulk of the solar energy that washes across the Earth.
SORCE is a ... next generation of monitoring solar irradiance... but SORCE is really going to make a giant step forward - we're looking at improvements at least in a factor of ten in the accuracy of both total irradiance and spectral irradiance... (BILL OCHS)
Tracking the total solar output is a crucial job. For the next five years, SORCE will add to a legacy of measurements begun in 1978 with the NIMBUS satellite. Those measurements continued with the UARS and SOHO platforms-- both still in orbit.
SORCE will be controlled from the University of Colorado where grad students and scientists will be waiting anxiously for data to shed light on the overarching questions -- How does the Sun's energy vary and how does that variation impact Earth?
Courtesy: NASA
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| ITEM (2): From The Sun to The Earth - Though an Earth Science Enterprise mission, SORCE will be focusing its radiometers, spectrometers, photodiodes, and bolometers on the Sun. With four instruments, it will orbit Earth 15 times a day and measure the Sun's radiative output (also called Total Solar Irradiance, or TSI) and analyze the Sun's energy in visible colors, as well as ultraviolet and infrared wavelengths that can be used to determine solar heating of Earth's oceans, ice, land and absorbing layers of the atmosphere. Its data will continue a 24-year legacy of monitoring that should start to explain and predict the effect of the Sun's radiation on the Earth's atmosphere and climate.
Courtesy: NASA / LASP
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| ITEM (3): The Tools of Exploration - SORCE carries four instruments to meet its goal of monitoring and linking solar output with climate on Earth. The Total Irradiance Monitor (TIM) will be tracking the Sun's cumulative total output over all its wavelengths, up to ten times more accurately than previous sensors. TIM will also record sensitive fluctuations in the Sun on a day-to-day basis. The Solar Stellar Irradiance Experiment (SOLSTICE) will contribute to the tracking of ultraviolet rays in our stratosphere, including UV-B, which leads to ozone destruction.
The Spectral Irradiance Monitor (SIM) will extend the wavelengths measured across the visible and near infrared, providing the first contiguous spaceborne observations at wavelengths that carry more than 90% of the Sun's energy, and which penetrate past the ozone layer to the Earth's surface, and into the upper layers of the oceans, driving the heating and photosynthesis on which all living systems depend. Finally the eXtreme ultraviolet Photometer System (XPS) will be making measurements of the shortest wavelength UV photons and even shorter wavelength soft X-rays. It will provide insight into the Sun's corona (atmosphere), solar events that impact satellite communications, and effects on the outermost layers of the Earth's atmosphere.
Courtesy: NASA
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| ITEM (4): Star of The Show - The Sun's link with Earth's short and long-term climate change is poorly understood. SORCE will determine how much solar irradiance changes within the Sun's 11-year solar cycle when sunspots and the associated solar activity give rise to varying amounts of near ultraviolet, visible and near infrared radiation that impacts our environment. This shot from the SOHO spacecraft which observes high energy events crucial for tracking space weather, but which only add a negligible amount of energy to the Sun's more abundant longer wavelength photons that SORCE will study.
Courtesy: NASA/ESA
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| ITEM (5): Reigning on Earth's Climate - Only about 70% of the solar energy that reaches Earth is absorbed, while the other 30% is reflected back into space by atmosphere and aerosols, ocean/land and clouds. A closer view reveals a delicate balance between absorption and reflection as well as a release of energy by rocks, air and sea warming and emitting increasing amounts of thermal radiation (heat) in the form of long-wave infrared light. This radiation allows Earth to lose heat at the same rate it gains from the Sun. Evidence is in the land/ocean interaction, the absorption of energy by clouds, water vapor and the greenhouse gas ozone, as well as the 20-24% absorbed and emitted back by clouds.
Courtesy: NASA
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| ITEM (6): The Solar Spectrum - Radiation from the Sun consists of electromagnetic waves that have a wide range of wavelengths. This animation shows where Earth absorbed the 70% of solar radiation and which parts of the spectrum reaches where. Only 1% of the Total Solar Irradiance is absorbed by the upper atmosphere - mostly UV radiation absorbed by stratospheric ozone. About 20 - 24% heads into the lower atmosphere (troposphere) and is absorbed by waver vapor, trace gases, clouds and darker aerosols. The remaining 46 - 50% of visible light penetrates the atmosphere and is absorbed by the land and the oceans.
Courtesy: NASA
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| ITEM (7): The Earth - This view of Earth's output energy (thermal energy emitted into space) from the Clouds and Earth's Radiant Energy System (CERES) instrument, housed on the Terra and Aqua satellites. Heat energy radiated from the Earth is shown in varying shades of yellow, red, blue and white. The brightest yellow areas, such as the Sahara Desert, are emitting the most energy out to space, while the dark blue polar regions and bright white clouds are the coldest areas on Earth, and are emitting the least energy.
Courtesy: NASA
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| ITEM (8): The Solar Cycle - The Sun's output fluctuates from days to centuries, but the most common cycle observed is the 11-year sunspot cycle (2000-2001 marked the approximate peak of the current cycle). The number of sunspots and associated faculae (bright regions on the Sun's surface which usually form before sunspots appear) observed go from as many as 200 spots per month, to as few as a dozen during minimum. The Sun's yearly average total irradiance during the cycle can change by 0.1% or 1.4 watts per square meter. It was close to a 0.5% difference in output that brought about the 'Little Ice Age' from 1645-1715. That was enough to freeze rivers in Europe and alter seasons in other parts of the world.
Courtesy: NASA/ESA
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| ITEM (9): The Sorce of The Radiation - The solar cycle varies as does the amount of sunspots and associated faculae on the Sun. Variations in solar output are due to a balance between decreases caused by sunspots (relatively cold bottlenecks of magnetic fields on the hot solar surface) and associated bright areas called faculae (relatively hotter groupings of magnetic fields). However, the effects of the faculae tend to beat out those of the sunspots so that the hot faculae raise the total solar output more than the cooler sunspots subtract. Here, solar activity goes from minimum to maximum.
Courtesy: NASA / Mauna Loa Solar Observatory
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| ITEM (10a): Case Study: The Little Ice Age - Unusually low solar activity (fewer sunspots observed) between 1645-1715, called the 'Maunder Minimum' likely triggered the 'Little Ice Age' in Europe and North America. A 2001 computer model seemed to confirm this long-held theory by proving that the decreased UV levels from the Sun created a stronger ozone layer, which altered the heating of the oceans. Winter temperatures cooled as much as 2 to 4 degrees F (1 C) - enough to freeze rivers and alter agriculture, economy, disease, etc. The model shows temperature anomalies with 1780 as an arbitrary baseline (neutral).
Courtesy: NASA
ITEM (10b): The Little Ice Age Revealed - Aert van der Neer's painting, "Sports on a Frozen River," was just one of many paintings showing the remarkable period where global temperatures differed enough to freeze rivers and cause other far-reaching consequences. Greenland was largely cut off by ice from 1410 to the 1720s and canals in Holland routinely froze solid. Glaciers advanced in the Alps, and iced waterways effectively sealed off Iceland in 1695. In Europe people held 'Frost Fairs' on their typically ice-free rivers where they skated and golfed on the ice.
Courtesy: The Metropolitan Museum of Art
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| ITEM (11): Historical Context: NIMBUS, UARS, SOHO - Prior to 1979 scientists did not even have accurate data on the total amount of energy output from the Sun. The Total Solar Irradiance (TSI) was considered a constant and used in models and equations. The launch of Nimbus-7 changed everything: it allowed for the study of sunlight without interference from the atmosphere. In fact Nimbus and the ACRIM instrument on the SMM satellite revealed the Sun's output changed by 0.1% from the 1970s through 1990s. More recently observations from UARS and SOHO confirmed a cyclical rise and fall of output within the solar cycle.
Courtesy: NASA / ESA
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| ITEM (12): Mission Operations - The SORCE spacecraft and instruments will be operated from the Laboratory for Atmospheric Physics (LASP) at the University of Colorado. Following spacecraft commissioning activities during the first 30 days of mission, SORCE will transmit data through the NASA Space/Ground Network at Wallops Island, Virginia and Santiago, Chile; to LASP and Goddard Space Flight Center twice per day. Located in Boulder, CO., LASP will operate SORCE for its lifetime of approximately five years with a unique staff consisting of university professionals, academic researchers, and University of Colorado students.
Courtesy: NASA / LASP
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| ITEM (13): B-Roll - Orbital Sciences Corporation built the SORCE spacecraft under contract to the Laboratory for Atmospheric and Space Physics at the University of Colorado. The spacecraft will be launched from a Pegasus XL at the Kennedy Space Center in Florida in January 2003. The Pegasus, an internally guided, 3-stage solid rocket, is mated to a carrier aircraft that will drop it at approximately 38,000 feet. The rocket will fall for about 5 seconds before firing its first stage rocket motor. The duration of a typical flight is approximately 11 minutes.
Courtesy: NASA
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| ITEM (14): Soundbites With Dr. Gary Rottman, Project Investigator ; Dr. Bob Cahalan, Project Scientist ; Bill Ochs, Project Manager; Tom Sparn, Project Manager
Courtesy: NASA
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Space Science Gallery