Frequently Asked Questions
1. How can I get satellite pictures of my house, my town, or some area so I can see buildings, streets and similar details?
2. Where can I get satellite pictures of hurricanes, storms, floods and similar events?
3. Can I use NOAA satellite pictures on my web site, in books or other publications, educational materials, or on television?
4. Can I see the NOAA satellites?
5. When do the NOAA satellites pass over my area?
6. I perform research that requires NOAA satellite data. How do I obtain these data?
7. Can I receive NOAA satellite data directly from the satellite?
8. I need a book on how to interpret satellite imagery and data. Can NOAA send me one?
9. What is the greenhouse effect, and is it affecting our climate?
10. Are greenhouse gases increasing?
11. Is the climate warming?
12. Are El Niños related to Global Warming?
1. How can I get satellite pictures of my house, my town, or some area so I can see buildings, streets, and similar details?
NOAA cannot provide these pictures. The NOAA satellites cannot provide this detail. These satellites were designed for observing weather systems and similar large features. See a sample image (of the typical detail and resolution provided by NOAA satellites. The smallest distance the NOAA satellites can resolve is 1 kilometer (a little more than 1/2 mile) under the best conditions. Very detailed satellite images usually must be obtained from commercial sources, for a fee. These would include, but are not limited to SPOT Image and others. Some very detailed satellite images over the United States can be found on the Terra Server.
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2. Where can I get satellite pictures of hurricanes, storms, floods and similar events?
Many web sites have satellite pictures, although some of the pictures, especially at commercial sites, may be copyrighted. NOAA has several sites with satellite and weather related pictures, including the Operational Special Events Imagery site, National Climatic Data Center, and NOAA Library. The most recent, up-to-date images from the NOAA GOES satellites are the GOES server.
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3. Can I use NOAA satellite pictures on my web site, in books or other publications, educational materials, or on television?
Yes, depending on where you get the pictures. If you get satellite pictures from a NOAA site, or generally, any other U.S. Federal government site, these pictures are from NOAA. As such, they can be used if you give credit to NOAA as the source of the picture. No other fee or permission is needed other than a credit. If you find a picture on a NOAA or other government site that has a credit for that picture to some person or organization other than NOAA, you CANNOT use it without permission of that person or organization. Commercial web sites (such as television stations, The Weather Channel, Intellicast, Accu-Weather, Kavouras-DTN, etc.) may have pictures from the NOAA satellites. The pictures have been modified by these organizations and are now copyrighted property; you cannot use them without express permission of the owner. Pictures you receive directly from a satellite with your own receiving equipment can be used with a credit to NOAA.
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4. Can I see the NOAA satellites?
Yes, but they are faint (about magnitude 5.5 at their brightest). The NOAA polar orbiting satellites are approximately 500 statute miles above the Earth, are relatively small (i.e. smaller than the Space Shuttle), and not very reflective. If you have a good viewing location away from large cities, where the Milky Way would be visible for instance, you can try to spot the NOAA satellites. The Heavens-Above web site can produce spotting information for any location worldwide. The GOES geostationary satellites are about 23,000 statute miles above the Equator and require a telescope to see them.
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5. When do the NOAA satellites pass over my area?
There are at least three web sites that interactively show the current location of the satellites, and what they are viewing. Try the NASA JTrack site, Heavens-Above in Germany, or the Earth Viewer.
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6. I perform research that requires NOAA satellite data. How do I obtain these data?
Most users can get the data they require from the NOAA Comprehensive Large Array-data Stewardship System (CLASS). The CLASS is an interactive search tool to find the data you need, and once the data sets have been retrieved, they can be downloaded from the CLASS ftp site. Small digital data sets are free.
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7. Can I receive NOAA satellite data directly from the satellite?
Yes. Some satellite imagery services can be received directly from the satellite using relatively simple, low-cost equipment. Many schools and private individuals are among those receiving data directly from the NOAA satellites. Consult our brief overview of the types of satellite direct readout data services. We also have a list of manufacturers of various types of receiving equipment used to receive NOAA satellite data.
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8. I need a book on how to interpret satellite imagery and data. Can NOAA send me one?
Such books are available commercially from scholarly and university publishers. NOAA does not publish such general references and textbooks, or collections of interesting or unusual satellite pictures.
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9. What is the greenhouse effect, and is it affecting our climate?
The greenhouse effect is unquestionably real and helps to regulate the temperature of our planet. It is essential for life on Earth and is one of Earth's natural processes. It is the result of heat absorption by certain gases in the atmosphere (called greenhouse gases because they effectively 'trap' heat in the lower atmosphere) and re-radiation downward of some of that heat. Water vapor is the most abundant greenhouse gas, followed by carbon dioxide and other trace gases. Without a natural greenhouse effect, the temperature of the Earth would be about zero degrees F (-18°C) instead of its present 57°F (14°C). The concern is not with the fact that we have a greenhouse effect, but whether human activities are leading to an enhancement of the greenhouse effect by the emission of greenhouse gases through fossil fuel combustion and deforestation.
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10. Are greenhouse gases increasing?
Human activity has been increasing the concentration of greenhouse gases in the atmosphere (mostly carbon dioxide from combustion of coal, oil, and gas; plus a few other trace gases). There is no scientific debate on this point. Pre-industrial levels of carbon dioxide (prior to the start of the Industrial Revolution) were about 280 parts per million by volume (ppmv), and current levels are greater than 380 ppmv and increasing at a rate of 1.9 ppm yr-1 since 2000. The global concentration of CO2 in our atmosphere today far exceeds the natural range over the last 650,000 years of 180 to 300 ppmv. According to the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios, by the end of the 21st century, we could expect to see carbon dioxide concentrations of anywhere from 490 to 1260 ppm (75-350% above the pre-industrial concentration).
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11. Is the climate warming?
Global surface temperatures have increased about 0.74°C (plus or minus 0.18°C) since the late-19th century, and the linear trend for the past 50 years of 0.13°C (plus or minus 0.03°C) per decade is nearly twice that for the past 100 years. The warming has not been globally uniform. Some areas (including parts of the southeastern U.S. and parts of the North Atlantic) have, in fact, cooled slightly over the last century. The recent warmth has been greatest over North America and Eurasia between 40 and 70°N. Lastly, seven of the eight warmest years on record have occurred since 2001 and the 10 warmest years have all occurred since 1995.
Recent analyses of temperature trends in the lower and mid- troposphere (between about 2,500 and 26,000 ft.) using both satellite and radiosonde (weather balloon) data show warming rates that are similar to those observed for surface air temperatures. These warming rates are consistent with their uncertainties and these analyses reconcile a discrepancy between warming rates noted on the IPCC Third Assessment Report (U.S. Climate Change Science Plan Synthesis and Assessment Report 1.1).
An enhanced greenhouse effect is expected to cause cooling in higher parts of the atmosphere because the increased "blanketing" effect in the lower atmosphere holds in more heat, allowing less to reach the upper atmosphere. Cooling of the lower stratosphere (about 49,000-79,500 ft.) since 1979 is shown by both satellite Microwave Sounding Unit and radiosonde data (see previous figure), but is larger in the radiosonde data likely due to uncorrected errors in the radiosonde data. Relatively cool surface and tropospheric temperatures, and a relatively warmer lower stratosphere, were observed in 1992 and 1993, following the 1991 eruption of Mt. Pinatubo. The warming reappeared in 1994. A dramatic global warming, at least partly associated with the record El Niño, took place in 1998. This warming episode is reflected from the surface to the top of the troposphere.
There has been a general, but not global, tendency toward reduced diurnal temperature range (DTR: the difference between daily high or maximum and daily low or minimum temperatures) over about 70% of the global land mass since the middle of the 20th century. However, for the period 1979-2005 the DTR shows no trend since the trend in both maximum and minimum temperatures for the same period are virtually identical; both showing a strong warming signal. A variety of factors likely contribute to this change in DTR, particularly on a regional and local basis, including changes in cloud cover, atmospheric water vapor, land use and urban effects.
Indirect indicators of warming such as borehole temperatures, snow cover, and glacier recession data agree substantially with the more direct indicators of recent warmth. Evidence such as changes in glacial mass balance (the amount of snow and ice contained in a glacier) is useful since it not only provides qualitative support for existing meteorological data, but glaciers often exist in places too remote to support meteorological stations. The records of glacial advance and retreat often extend back further than weather station records, and glaciers are usually at much higher altitudes than weather stations, allowing scientists more insight into temperature changes higher in the atmosphere.
Large-scale measurements of sea-ice have only been possible since the satellite era, but through looking at a number of different satellite estimates, it has been determined that September Arctic sea ice has decreased between 1973 and 2007 at a rate of about -10% +/- 0.3% per decade. Sea ice extent for September for 2007 was by far the lowest on record at 4.28 million square kilometers, eclipsing the previous record low sea ice extent by 23%. Sea ice in the Antarctic has shown very little trend over the same period, or even a slight increase since 1979. Though extending the Antarctic sea-ice record back in time is more difficult due to the lack of direct observations in this part of the world.
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12. Are El Niños related to Global Warming?
El Niños are not caused by global warming. Clear evidence exists from a variety of sources (including archaeological studies) that El Niños have been present for thousands, and some indicators suggest maybe millions, of years. However, it has been hypothesized that warmer global sea surface temperatures can enhance the El Niño phenomenon, and it is true that El Niños have been more frequent and intense in recent decades. Whether El Niño occurrence changes with climate change is a major research question.
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