| GLOSSARY |
Our comprehensive earth science glossary is available to assist in your understanding of the MY NASA DATA microsets, lesson plans and computer tools. Please select the first letter of the word you wish to check for a definition and further information. |
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| GIS: |
| Geographical Information Systems; merges computerized data with its spatial location on a digital map.
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| glacier: |
| a body of moving ice on the land, formed by accumulation of snow.
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Image courtesy MY NASA DATA |
| G |
| global warming: |
| an increase of Earth's average temperature which could lead to climate change. Scientists are concerned that human activities are altering the concentration of greenhouse gases and might cause such global warming. See definition of greenhouse effect.
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| GPS: |
| Global Positioning System; a satellite-receiver system used to determine a precise location on or above Earth's surface.
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| GRACE: |
| the Gravity Recovery and Climate Experiment. GRACE maps variations in the Earth's gravity field by making accurate measurements of the distance between two specially-designed satellites using an ultra-precise microwave ranging system. The gravity variations that GRACE is observing include changes due to surface and deep currents in the ocean, runoff and ground water storage on land masses, exchanges between ice sheets or glaciers and the oceans, and variations of mass within the Earth.
More Information
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Image courtesy JPL |
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| gravity: |
| A physical force that is responsible for the attraction between any two bodies that have mass. The Earth's gravity is what keeps us from floating into space.
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| greenhouse effect: |
| The greenhouse effect is a naturally occurring process that aids in heating the Earth's surface and atmosphere. It results from the fact that certain atmospheric gases absorb longwave radiation from the Earth's surface. Without the greenhouse effect, life on this planet would probably not exist as we know it since the average temperature of the Earth would be a chilly -18 degrees Celsius, rather than the present 15 degrees Celsius. However, it is theorized that manmade perturbations to the greenhouse gases such as carbon dioxide may be causing global warming.
EPA Global Warming Kids Site
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| G |
| grid box: |
| a four-sided geographical area defined by given latitude and longitude boundaries, used for the representation of data for an area of Earth's surface or atmosphere.
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| G |
| Gulf Stream: |
| a warm ocean current that flows from the Gulf of Mexico northeastward along the coast of North America and across the North Atlantic Ocean to the British Isles.
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| gyre: |
| a large-scale circular current of water driven by winds at the ocean surface. Several gyres drive the ocean surface circulation patterns of Earth.
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Image courtesy UWGB |
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