Glosario

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  1. The process in which radiant energy is retained by a substance. A further process always results from absorption, that is, the irreversible conversion of the absorbed radiation into some other form of energy within and according to the nature of the...
  2. A remote-sensing system that transmits its own radiation to detect an object or area for observation and receives the reflected or transmitted radiation. Radar is an example of an active system. Compare with passive system. Source: NASA (http://...
  3. Particles of liquid or solid dispersed as a suspension in gas. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  4. The existence in the air of substances in concentrations that are determined unacceptable. Contaminants in the air we breathe come mainly from manufacturing industries, electric power plants, automobiles, buses, and trucks. Source: NASA (http://...
  5. The ratio of the outgoing solar radiation reflected by an object to the incoming solar radiation incident upon it. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  6. Sudden spurts of algal growth due to greatly increased amounts of phosphorus entering the aquatic ecosystem from sewage systems and agricultural fertilizers. Excessive growth of the algae causes destruction of many of the higher links of the food...
  7. The magnitude of the displacement of a wave from a mean value. For a simple harmonic wave, it is the maximum displacement from the mean. For more complex wave motion, amplitude is usually taken as one-half of the mean distance (or difference)...
  8. Made by people or resulting from human activities. Usually used in the context of emissions that are produced as a result of human activities. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  9. The point in its orbit when a planet is farthest from the sun. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  10. On an elliptical orbit path, the point at which a satellite is farthest from the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  11. Layer of water-bearing permeable rock, sand, or gravel capable of providing significant amounts of water. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  12. The point in an orbit (longitude) at which a satellite crosses the equatorial plane from south to north. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  13. The air surrounding the Earth, described as a series of shells or layers of different characteristics. The atmosphere, composed mainly of nitrogen and oxygen with traces of carbon dioxide, water vapor, and other gases, acts as a buffer between Earth...
  14. The range of wavelengths at which water vapor, carbon dioxide, or other atmospheric gases only slightly absorb radiation. Atmospheric windows allow the Earth's radiation to escape into space unless clouds absorb the radiation. See greenhouse effect...
  15. The direction, in degrees referenced to true north, that an antenna must be pointed to receive a satellite signal (compass direction). The angular distance is measured in a clockwise direction. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  16. Process by which up to 25% of radiant energy from the sun is reflected or scattered away from the surface by clouds. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  17. In radio, a continuous sequence of broadcasting frequencies within given limits. In radiometry, a relatively narrow region of the electromagnetic spectrum to which a remote sensor responds; a multispectral sensor makes measurements in a number of...
  18. The total range of frequency required to pass a specific modulated signal without distortion or loss of data. The ideal bandwidth allows the signal to pass under conditions of maximum AM or FM adjustment. (Too narrow a bandwidth will result in loss...
  19. The combination of antenna azimuth and elevation required to point (aim) an antenna at a spacecraft. The bearing for geostationary (i.e., GOES) satellites is constant. The bearing for polar-orbiting satellites varies continuously. Source: NASA (http...
  20. Organic nonfossil material of biological origin. For example, trees and plants are biomass. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  21. Part of the Earth system in which life can exist, between the outer portion of the geosphere and the inner portion of the atmosphere. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  22. The plant and animal life of a region or area. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  23. An ideal emitter which radiates energy at the maximum possible rate per unit area at each wavelength for any given temperature. A blackbody also absorbs all the radiant energy incident on it; i.e., no energy is reflected or transmitted. Source: NASA...
  24. A severe weather condition characterized by low temperatures and strong winds (greater than 35 mph) bearing a great amount of snow, either falling or blowing. When these conditions persist after snow has stopped falling, it is called a ground...
  25. Northern; from the Greek name for the Goddess of the North Wind. A boreal forest is the set of forest ecosystems than can survive in the north. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  26. A measure of the intensity of radiation thermally emitted by an object, given in units of temperature because there is a proportional correlation between the intensity of the radiation emitted and physical temperature of the radiating body. Source:...
  27. bus
    The basic frame of a satellite system that includes the propulsion and stabilization systems but not the instruments or data systems. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  28. Act of comparing an instrument's measuring accuracy to a known standard. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  29. The layer formed naturally by the leaves and branches of trees and plants. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  30. an organic compound present in the cells of all living organisms and a major organic nutrient for human beings; consists of carbon, hydrogen, and oxygen, and makes up sugar, starch, and cellulose. Source: NASA (http://earthobservatory.nasa.gov/...
  31. A minor but very important component of the atmosphere, carbon dioxide traps infrared radiation. Atmospheric CO2 has increased about 25 percent since the early 1800s, with an estimated increase of 10 percent since 1958 (burning fossil fuels is the...
  32. The science of mapmaking. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  33. CCS
    The UK Cabinet Office Civil Contingencies Secretariat (CCS) enhances the UK's ability to prepare for, respond to and recover from emergencies.
  34. Temperature scale proposed by Swedish astronomer Anders Celsius in 1742. A mixture of ice and water is zero on the scale; boiling water is designated as 100 degrees. A degree is defined as one hundredth of the difference between the two reference...
  35. European Organization for Nuclear Research
  36. A family of compounds of chlorine, fluorine, and carbon, entirely of industrial origin. CFCs include refrigerants, propellants for spray cans (this usage is banned in the U.S., although some other countries permit it) and for blowing plastic-foam...
  37. Chlorophyll is a green compound found in leaves and green stems of plants. The intense green color of chlorophyll is due to its strong absorbencies in the red and blue regions of the spectrum, and because of these absorbencies the light it reflects...
  38. A type of cloud composed of ice crystals and shaped in the form of hairlike filaments. It is formed at an altitude of approximately 29,000 feet. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  39. The outcome or product of the set of activities conducted by an agency or group of agencies with the aim of preventing, mitigating and responding to the effects of disasters on persons, on property and the environment.
  40. The term 'climate change' is sometimes used to refer to all forms of climatic inconsistency, but because the Earth's climate is never static, the term is more properly used to imply a significant change from one climatic condition to another. In...
  41. A quantitative way of representing the interactions of the atmosphere, oceans, land surface, and ice. Models can range from relatively simple to quite comprehensive. Also see General Circulation Model. Source: NASA (http://earthobservatory.nasa.gov/...
  42. The five physical components (atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere) that are responsible for the climate and its variations. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  43. Science dealing with climate and climate phenomena. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  44. Reflectivity that varies from less than 10% to more than 90% of the insolation and depends on drop sizes, liquid water content, water vapor content, thickness of the cloud, and the sun's zenith angle. The smaller the drops and the greater the liquid...
  45. The difference between the radiation budget components for average cloud conditions and cloud-free conditions. Roughly speaking, clouds increase the albedo from 15 to 30%, which results in a reduction of absorbed solar radiation of about 50 W/m^2....
  46. A visible mass of liquid water droplets suspended in the atmosphere above Earth's surface. Clouds form in areas where air rises and cools. The condensing water vapor forms small droplets of water (0.012 mm) that, when combined with billions of other...
  47. IASC-designated groupings of humanitarian organizations (both UN and non-UN) in each of the main sectors of humanitarian action. They operate at both global and country level (although they are not necessarily congruent). At the global level they...
  48. National Centre for Space Studies
  49. China National Space Administration
  50. National Space Activities Commission
  51. Change of a substance to a denser form, such as gas to a liquid. The opposite of evaporation. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  52. The transfer of heat from one substance to another by direct contact. Denser substances are better conductors; the transfer is always from warmer to colder substances. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  53. An evergreen, cone-bearing tree, as a fir or pine. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  54. The rising of warm air and the sinking of cool air. Heat mixes and moves air. When a layer of air receives enough heat from the Earth's surface, it expands and moves upward. Colder, heavier air flows under it which is then warmed, expands, and rises...
  55. Mexico Campus of the Regional Centre for Space Science and Technology Education for Latin America and the Caribbean
  56. One of the interrelated components of the Earth's system, the cryosphere is frozen water in the form of snow, permanently frozen ground (permafrost), floating ice, and glaciers. Fluctuations in the volume of the cryosphere cause changes in ocean sea...
  57. CSA
    Canadian Space Agency
  58. Clouds forming in the troposphere which are vertically formed with flat bases and fluffy, rounded tops. They have often been described as cauliflower-like in structure. They occur at heights of 500-6000 meters in elevation from the earth and most...
  59. An area of low pressure where winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. See anticyclone, wind. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  60. A collection of facts, concepts or instructions in a formalized manner suitable for communication or processing by human beings or by computer. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  61. A logically meaningful grouping or collection of similar or related data. Data having mostly similar characteristics (source or class of source, processing level and algorithms, etc.) Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  62. Shedding leaves at the end of the growing season. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  63. Official issuance of a state of emergency or calamity upon the occurrence of a large-scale event (hazard), in order to activate measures aimed at responding to the needs arising as a consequence of the disaster. The declaration of a disaster by a...
  64. The angular distance from the equator to the satellite, measured as positive north and negative south. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  65. Those practices or processes that result in the change of forested lands to non-forest uses. This is often cited as one of the major causes of the enhanced greenhouse effect for two reasons: 1) the burning or decomposition of the wood releases...
  66. A unit of angular measure represented by the symbol o. The circumference of a circle contains 360 degrees. When applied to the roughly spherical shape of the Earth for geographic and cartographic purposes, degrees are each divided into 60 minutes....
  67. The fan-shaped area at the mouth or lower end of a river, formed by eroded material that has been carried downstream and dropped in quantities larger than can be carried off by tides or currents. Source: NASA (http://earthobservatory.nasa.gov/...
  68. Process by which water changes phase directly from vapor into a solid without first becoming a liquid. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  69. The point in a satellite's orbit at which it crosses the equatorial plane from north to south. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  70. A land area so dry that little or no plant or animal life can survive. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  71. The man-made or natural formation of desert from usable land. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  72. A device in a radiometer that senses the presence and intensity of radiation. The incoming radiation is usually modified by filters or other optical components that restrict the radiation to a specific spectral band. The information can either be...
  73. Accumulated organic debris from dead organisms, often an important source of nutrients in a food web. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  74. In signal processing this refers to the representation of quantities in discrete units. The information is contained and manipulated as a series of discrete numbers as opposed to an analog representation where the information is represented as a...
  75. A representation of the topography of the Earth in digital format, that is, by coordinates and numerical descriptions of altitude. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  76. A serious disruption of the functioning of society, causing widespread human, material or environmental losses which exceed the ability of the affected society to cope using only its own resources. A disaster is triggered by a natural or...
  77. The organization and management of resources and responsibilities to address response and recovery. This definition implies that disaster management comprises those activities conducted once a disaster has taken place and excludes those activities...
  78. The complete set of phases related to disasters and their management (prevention, mitigation, preparedness, response, rehabilitation, reconstruction and recovery). The mission statement of UN-SPIDER makes reference to the provision of universal...
  79. The potential disaster losses, in lives, health status, livelihoods, assets and services, which could occur to a particular community or a society over some specified future time period. Disaster Risk is represented through the combination of hazard...
  80. Disaster risk management aims to avoid, lessen or transfer the adverse effects of hazards through prevention, mitigation and preparedness. This definition would imply that disaster risk management comprises activities conducted before the disaster...
  81. The set of all measures carried out in the disaster management cycle, but making explicit reference to those conducted before and after the disaster. It is important to recognize that different agencies work in disaster risk management and in...
  82. The set of agencies, organizations and institutions at local, national, regional and international levels that focus their activities on prevention, mitigation and preparedness.
  83. Performed in twenty-four hours, such as the diurnal rotation of the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  84. DLR
    German Aerospace Center
  85. Disaster Monitoring Constellation International Imaging
  86. The standard way to express ozone amounts in the atmosphere. One DU is 2.7 x 10 exp 16 (10 to the 16th power) ozone molecules per square centimeter. One Dobson unit refers to a layer of ozone that would be 0.001 cm thick under conditions of standard...
  87. The apparent change in frequency of sound or light waves, varying with the relative velocity of the source and the observer. If the source and observer draw closer together, the frequency is increased. Named for Christian Doppler, Austrian...
  88. The weather radar system that uses the Doppler shift of radio waves to detect air motion that can result in tornadoes and precipitation, as previously-developed weather radar systems do. It can also measure the speed and direction of rain and ice,...
  89. DRR
    Disaster-Risk Reduction
  90. The set of capacities needed to generate and disseminate timely and meaningful warning information to enable individuals, communities and organizations threatened by a hazard to prepare and to act appropriately and in sufficient time to reduce the...
  91. The observation and/or study of an area, object or phenomenon from an aerial distance, frequently using data collected by satellite.
  92. A series of small- to intermediate-sized spacecraft that is the centerpiece of NASA's Earth Science Enterprise (ESE). Planned for launch beginning in 1999, each of the EOS spacecraft will carry a suite of instruments designed to study global climate...
  93. The system that will manage a dataset of Earth science observations to be collected over a 15-year period. Existing data indicates that the Earth is changing, and that human activity increasingly contributes to this change. To monitor these changes...
  94. A project that is responsible for providing scientific and other users access to data from NASA's Earth Science Enterprise. The ESDIS Project provides this access through the development and operation of the Earth Observing System (EOS) Data and...
  95. The Earth regarded as a unified system of interacting components, including geosphere (land), atmosphere (air), hydrosphere (water and ice), and biosphere (life). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  96. An integrated approach to the study of the Earth that stresses investigations of the interactions among the Earth's components in order to explain Earth dynamics, evolution, and global change. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  97. One of six Keplerian elements, it describes the shape of an orbit. In the Keplerian orbit model, the satellite orbit is an ellipse, with eccentricity defining the 'shape' of the ellipse. When e=0, the ellipse is a circle. When e is very near 1, the...
  98. Science dealing with the interrelationships between living organisms and their environments. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  99. Any natural unit or entity including living and non-living parts that interact to produce a stable system through cyclic exchange of materials. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  100. A warming of the surface waters of the eastern equatorial Pacific that occurs at irregular intervals of 2-7 years, usually lasting 1-2 years. Along the west coast of South America, southerly winds promote the upwelling of cold, nutrient-rich water...
  101. Energy propagated as time-varying electric and magnetic fields. These two fields are inextricably linked as a single entity since time-varying electric fields produce time-varying magnetic fields and vice versa. Light and radar are examples of...
  102. The entire range of radiant energies or wave frequencies from the longest to the shortest wavelengths--the categorization of solar radiation. Satellite sensors collect this energy, but what the detectors capture is only a small portion of the entire...
  103. Method of travel for radiant energy (all energy is both particles and waves), so called because radiant energy has both magnetic and electrical properties. electromagnetic waves are produced when electric charges change their motion. Whether the...
  104. The angle at which an antenna must be pointed above the horizon for optimal reception from a spacecraft. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  105. Bodies in space orbit in elliptical rather than circular orbits because of factors such as gravity and drag. The point where the orbiting satellite is closest to Earth is the perigee, sometimes called peri-apsis or perifocus. The point where the...
  106. A disruption of the functioning of society, causing human, material or environmental damages and losses which do not exceed the ability of the affected society to cope using only its own resources.
  107. The set of agencies, organizations and institutions at local, national, regional and international levels that focus their activities on response, rehabilitation, reconstruction and recovery. The term “humanitarian response community” is mentioned...
  108. The ratio of the radiation emitted by a surface to that emitted by a black body at the same temperature. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  109. The natural greenhouse effect has been enhanced by anthropogenic emissions of greenhouse gases. Increased concentrations of carbon dioxide, methane, and nitrous oxide, CFCs, HFCs, PFCs, SF6, NF3, and other photochemically important gases caused by...
  110. Interacting parts of a single global system of climate fluctuations. ENSO is the most prominent known source of interannual variability in weather and climate around the world, though not all areas are affected. The Southern Oscillation (SO) is a...
  111. The complex of physical, chemical, and biological factors in which a living organism or community exists. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  112. ESA
    European Space Agency
  113. A bay that formed when a broad river valley was submerged by rising sea level or a sinking coast. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  114. European Organisation for the Exploitation of Meteorological Satellites
  115. The process whereby a body of water becomes rich in dissolved nutrients through natural or man-made processes. This often results in a deficiency of dissolved oxygen, producing an environment that favors plant over animal life. Source: NASA (http://...
  116. Change from a liquid (more dense) to a vapor or gas (less dense) from. When water is heated it becomes a vapor that increases humidity. Evaporation is the opposite of condensation. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  117. The sum of evaporation and plant transpiration. Potential evapotranspiration is the amount of water that could be evaporated or transpired at a given temperature and humidity, if there was plenty of water available. Actual evapotranspiration can not...
  118. Temperature scale designed by the German scientist Gabriel Fahrenheit in 1709, based upon water freezing at 32 degrees Fahrenheit and water boiling at 212 degrees Fahrenheit under standard atmospheric pressure. Compare with centigrade. Source: NASA...
  119. A color imaging process which produces an image of a color that does not correspond to the true or natural color of the scene (as seen by our eyes). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  120. Electromagnetic radiation, longer than the thermal infrared, with wavelengths between about 25 and 1000 micrometers. See electromagnetic spectrum. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  121. A fracture in rock along which one side has moved with respect to the other. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  122. U.S. Federal Emergency Management Agency. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  123. The range of angles that are scanned or sensed by a system or instrument, measured in degrees of arc. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  124. The nearly flat portion of a river (stream) valley adjacent to the river (stream) channel; it is built by sediment deposited during floods and is covered by water during a flood. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  125. Carbon-fluorine compounds that often contain other elements such as hydrogen, chlorine, or bromine. Common fluorocarbons include chlorofluorocarbons and related compounds (also know as ozone depleting substances). Source: NASA (http://...
  126. Number of cycles and parts of cycles completed per second. F=1/T, where T is the length of one cycle in seconds. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  127. Global Climate Observing System
  128. GEO
    Group on Earth Observation
  129. A branch of applied mathematics concerned with measuring the shape of the Earth and describing variations in the Earth's gravity field. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  130. The study of the Earth's motions, including rotation, tectonics, ocean tides, and structure (i.e., core, mantle). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  131. A system for archiving, retrieving, and manipulating data that has been stored and indexed according to the geographic coordinates of its elements. The system generally can utilize a variety of data types, such as imagery, maps. table, etc. Source:...
  132. The study of present-day landforms, including their classification, description, nature, origin, development, and relationships to underlying structures. Also the history of geologic changes as recorded by these surface features. The term is...
  133. Relating to the study of the physical characteristics and properties of the solid earth, its air and waters, and its relationship to space phenomena. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  134. The physical elements of the Earth's surface crust, and interior. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  135. Describes an orbit in which a satellite is always in the same position (appears stationary) with respect to the rotating Earth. The satellite travels around the Earth in the same direction, at an altitude of approximately 35,790 km (22,240 statute...
  136. Synchronous with respect to the rotation of the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  137. A multi-year surplus accumulation of snowfall in excess of snowmelt on land and resulting in a mass of ice at least 0.1 km2 in area that shows some evidence of movement in response to gravity. A glacier may terminate on land or in water. Glacier ice...
  138. The long-term fluctuations in temperature, precipitation, wind, and all other aspects of the Earth's climate. External processes, such as solar-irradiance variations, variations of the Earth's orbital parameters (eccentricity, precession, and...
  139. All of the activities required to specify a global variable, such as ozone. These activities range from data acquisition to the generation of a data-analysis product, and include estimates of the uncertainties in that product. A global measurement...
  140. Space-based radio positioning systems that provide 240-hour, three dimensional position, velocity and time information, in any weather conditions, to suitable equipped users anywhere on the surface of the Earth, as well as airborne and space users.
  141. A system consisting of 25 satellites in 6 orbital planes at 20,000 km altitude with 12 hr periods, used to provide highly precise position, velocity and time information to users anywhere on Earth or in its neighborhood at any time. Source: NASA (...
  142. An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past as the result of natural influences, but the term is most often used to refer to the warming predicted to occur as a result of increased...
  143. The warming of an atmosphere by its absorbing and reemitting infrared radiation while allowing shortwave radiation to pass on through. Certain gaseous components of the atmosphere, called greenhouse gases, transmit the visible portion of solar...
  144. A gaseous component of the atmosphere contributing to the greenhouse effect. Greenhouse gases are transparent to certain wavelengths of the sun's radiant energy, allowing them to penetrate deep into the atmosphere or all the way into the Earth's...
  145. The inclination of a satellite, together with its orbital altitude and the period of its orbit, creates a track defined by an imaginary line connecting the satellite and the Earth's center. The intersection on the line with the Earth's surface is...
  146. The area or region where a particular type of plant or animal lives and grows. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  147. A dangerous phenomenon, substance, human activity or condition that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. Hazards arise...
  148. Severe tropical storms whose winds exceed 74 mph. Hurricanes originate over the tropical and subtropical North Atlantic and North Pacific oceans, where there is high humidity and light wind. These conditions prevail mostly in the summer and early...
  149. The study of fluid motion and fluid-boundary interaction. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  150. The process of evaporation, vertical and horizontal transport of vapor, condensation, precipitation, and the flow of water from continents to oceans. It is a major factor in determining climate through its influence on surface vegetation, the clouds...
  151. The science that deals with global water (both liquid and solid), its properties, circulation, and distribution, on and under the Earth's surface and in the atmosphere through evapotranspiration or is discharged into oceans. Source: NASA (http://...
  152. The totality of water encompassing the Earth, comprising all the bodies of water, ice, and water vapor in the atmosphere. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  153. describes a sensor that observes hundreds or thousands of virtually continuous wavelengths of electromagnetic energy, or imagery from such a sensor. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  154. A satellite instrument that measures and maps the Earth and its atmosphere. Imager data are converted by computer into pictures. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  155. Latin for 'in original place.' Refers to measurements made at the actual location of the object or material measured. Compare remote sensing. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  156. One of the six Keplerian elements, it indicates the angle of the orbit plane to the central body's equator. See Keplerian elements for diagram. The elliptical path of a satellite orbit lies in a plane known as the orbital plane. The orbital plane...
  157. All of the means and mechanisms for data receipt, processing, storage, retrieval, and analysis. Information Systems can be designed for storage and dissemination of a variety of data products--including primary data sets and both intermediate and...
  158. Infrared is electromagnetic radiation whose wavelength spans the region from about 0.7 to 1000 micrometers (longer than visible radiation, shorter than microwave radiation). Remote sensing instruments work by sensing radiation that is naturally...
  159. National Institute for Space Research in Brazil
  160. The International Geosphere-Biosphere Programme (IGBP) is an interdisciplinary scientific activity established and sponsored by the International Council for Science (ICSU). The program was instituted by ICSU in 1986, and the IGBP Secretariat was...
  161. The International System of Units prescribes the symbols and prefixes shown in the table to form decimal multiples and submultiples of SI units. The following examples illustrate the use of these prefixes: 0.000,001 meters = 1 micrometer = 1°m 1000...
  162. A discontinuous belt of thunderstorms paralleling the equator and marking the convergence of the northern and southern hemisphere surface trade winds. See El Niño's Extended Family. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  163. Lines drawn on a weather map joining places of equal barometric pressure. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  164. Of or indicating equality of temperature. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  165. Lines connecting points of equal temperature on a weather map. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  166. Indian Space Research Organisation
  167. ITU
    International Telecommunication Union
  168. Japan Aerospace Exploration Agency
  169. Korea Aerospace Research Institute
  170. The standard unit of thermodynamic temperature. It is defined as 1/273.16 of the temperature of the triple point of water above absolute zero. The symbol for this is K. Kelvin is measured by the same temperature steps as Celsius but is shifted...
  171. Radar and microwave band in which the wavelengths vary from 1.67-2.4 cm. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  172. A period of stronger-than-normal trade winds and unusually low sea-surface temperatures in the central and eastern tropical Pacific Ocean; the opposite of El Niño. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  173. The characteristics of a land surface as determined by its spectral signature (the unique way in which a given type of land cover reflects and absorbs light). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  174. Indonesian National Institute of Aeronautics and Space
  175. Active instrument that produces discretely coherent pulses of light (light waves with no phase differences, or with predictable phases differences, are said to be coherent). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  176. The use of lasers to measure distances. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  177. The heat that is either released or absorbed by a unit mass of a substance when it undergoes a change of state, such as during evaporation, condensation, or sublimation. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  178. The angle between a perpendicular at a location, and the equatorial plane of the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  179. lava that piles up over a volcanic vent, usually in a rounded mass. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  180. The area of foliage per unit area of ground. Conventionally this refers to the ratio of the area of the upper side of the leaves in a canopy projected onto a flat surface to the area of the surface under the canopy. Occasionally this has been used...
  181. Acronym for 'Light Detection and Ranging,' a technique for performing accurate remote measurements of atmospheric trace gas concentration over ranges of several meters to tens of kilometers. This is done by probing the absorption lines of the gases...
  182. 1. Form of radiant energy that acts upon the retina of the eye, optic nerve, etc., making sight possible. This energy is transmitted at a velocity of about 186,000 miles per second by wavelike or vibrational motion. 2. A form of radiant energy...
  183. A discharge of atmospheric electricity accompanied by a vivid flash of light. During thunderstorms, static electricity builds up within the clouds. A positive charge builds in the upper part of the cloud, while a large negative charge builds in the...
  184. The component of the Earth's surface comprising the rock, soil, and sediments. It is a relatively passive component of the climate system, and its physical characteristics are treated as fixed elements in the determination of climate. Source: NASA (...
  185. The angular distance from the Greenwich meridian (0 degree), along the equator. This can be measured either east or west to the 180th meridian (180 degrees) or 0 degree to 360 degrees W. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  186. The radiation emitted in the spectral wavelength greater than 4 micrometers corresponding to the radiation emitted from the Earth and atmosphere. It is sometimes referred to as 'terrestrial radiation' or 'infrared radiation,' although somewhat...
  187. A horizontal area where the atmospheric pressure is less than it is in adjacent areas. Since air always moves from areas of high pressure to areas of low pressure, air from these adjacent areas of higher pressure will move toward the low pressure...
  188. The average height of the sea surface, based upon hourly observation of the tide height on the open coast or in adjacent waters that have free access to the sea. In the United States, it is defined as the average height of the sea surface for all...
  189. (mbps) Millions of bits per second. A unit of information transfer rate -- e.g. Ethernet can carry 10 mbps. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  190. The upper boundary of the mesosphere where the temperature of the atmosphere reaches its lowest point. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  191. The atmospheric layer above the stratosphere, extending from about 50 to 85 kilometers altitude. The temperature generally decreases with altitude. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  192. Information describing the content or utility of a data set. For example, the dates on which data were procured are metadata. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  193. a solid mass of mineral or rock matter that has fallen to the earth's surface from outer space without being completely vaporized in the atmosphere. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  194. Study of the atmosphere and its phenomena. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  195. A hydrocarbon that is a greenhouse gas. Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and oil, coal production...
  196. One millionth of a meter, used to measure wavelengths in the electromagnetic spectrum. Also known as a "micron" or µm. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  197. Electromagnetic radiation with wavelengths between about 1000 micrometers and one meter. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  198. Electromagnetic radiation between the near infrared and the thermal infrared, about 2-5 micrometers. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  199. One thousandth of a bar, a unit of atmospheric pressure. The average atmospheric pressure at sea level is 1.01325 bars or 1013.25 mb. See pascal (Pa), atmospheric pressure. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  200. The lessening or limitation of the adverse impacts of hazards and related disasters. In UN-SPIDER Mitigation is used to encompass those measures aimed at reducing the exposition to a hazard and vulnerability
  201. A mathematical representation of a process, system, or object developed to understand its behavior or to make predictions. The representation always involves certain simplifications and assumptions. Source: NASA (http://earthobservatory.nasa.gov/...
  202. A name for seasonal winds, first applied to the winds over the Arabian Sea that blow for six months from the northeast and for six months from the southwest. The term has been extended to similar winds in other parts of the world (i.e., the...
  203. Point on Earth directly beneath a satellite, the opposite of zenith. Compare with subsatellite point. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  204. National Disaster Management Organisation, Ghana
  205. One billionth of a meter. Nanometers are used to measure wavelengths in the electromagnetic spectrum. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  206. A nautical mile is a unit of distance equal to 1,852 meters. The length of the nautical mile is very close to the mean value of the length of 1 minute of latitude, which varies from approximately 1,843 meters at the equator to 1,861.6 meters at the...
  207. Electromagnetic radiation with wavelengths from just longer than the visible (about 0.7 micrometers) to about two micrometers. See electromagnetic spectrum. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  208. A gas consisting of one atom of nitrogen and two atoms of oxygen. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  209. Gases consisting of one molecule of nitrogen and varying numbers of oxygen molecules. Nitrogen oxides are produced in the emissions of vehicle exhausts and from power stations. In the atmosphere, nitrogen oxides can contribute to formation of...
  210. A powerful greenhouse gas with a global warming potential of 320. Major sources of nitrous oxide include soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and...
  211. National Oceanic and Atmospheric Administration
  212. US National Oceanic and Atmospheric Administration
  213. An index, or scale, of vegetation conditions based on differences in the amount of visible and near-infrared light reflected from plants on Earth's surface. A vegetation index is a gauge of plant health, productivity, and density. Plant leaves...
  214. a change in the color of the ocean surface as a result of sediment, organic matter, or phytoplankton, all of which can change how the ocean surface reflects and absorbs sunlight. In a natural-color (photo-like) image from space, the clear waters of...
  215. United Nations Office for the Coordination of Humanitarian Affairs
  216. In calculating the transfer of radiant energy, the mass of an absorbing or emitting material lying in a vertical column of unit cross-sectional area and extending between two specified levels. Also, the degree to which a cloud prevents light from...
  217. The path described by a heavenly body in its periodic revolution. Earth satellite orbits with inclinations near 0 degree are called equatorial orbits because the satellite stays nearly over the equator. Orbits with inclinations near 90 degrees are...
  218. An imaginary gigantic flat plate containing an Earth satellite's orbit. The orbital plane passes through the center of the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  219. An almost colorless, gaseous form of oxygen with an odor similar to weak chlorine. A relatively unstable compound of three atoms of oxygen, ozone constitutes--on the average--less than one part per million (ppm) of the gases in the atmosphere (peak...
  220. A large area of intense stratospheric ozone depletion over the Antarctic continent that typically occurs annually between late August and early October, and generally ends in mid-November. This severe ozone thinning has increased conspicuously since...
  221. The layer of ozone that begins approximately 15 km above Earth and thins to an almost negligible amount at about 50 km, shields the Earth from harmful ultraviolet radiation from the sun. The highest natural concentration of ozone (approximately 10...
  222. Sensitive to all or most of the visible spectrum. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  223. A constant whose values determine the specific form or characteristics of an expression. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  224. A unit of measure used for very small quantities, it is equal to the ratio of the weight or volume of one component of a mixture to a billion weights or volumes of the mixture. When based on weight (ppbw), it is equal to the weight or mass of the...
  225. Unit of atmospheric pressure named in honor of Blaise Pascal (1632-1662), whose experiments greatly increased knowledge of the atmosphere. A pascal is the force of one newton acting on a surface area of one square meter. It is the unit of pressure...
  226. A system sensing only microwave radiation emitted by the object being viewed or reflected by the object from a source other than the system. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  227. A system sensing only radiation emitted by the object being viewed or reflected by the object from a source other than the system. See active system. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  228. The instruments that are accommodated on a spacecraft. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  229. On an elliptical orbit path, the point where a satellite is closest to the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  230. The point in the orbit of a planet or comet which is nearest the Sun (as opposed to the aphelion, which is the point in the orbit farthest from the Sun). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  231. pH
    A symbol for the degree of acidity or alkalinity of a solution. Expressed as a negative logarithm of the hydrogen ion concentration in a solution, pH = -log10[H+]. If the hydrogen ion concentration of a solution increases, the pH will decrease, and...
  232. Microscopic, plant-like marine organisms (mostly algae and diatoms), which are responsible for most of the photosynthetic activity in the oceans. Phytoplankton are the base of the ocean food web, and they absorb about as much carbon dioxide from the...
  233. Pixel, short for picture element, is the ground area corresponding to a single element of a digital image data set. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  234. The fraction of incident solar radiation that is reflected by a planet and returned to space. The planetary albedo of the Earth-atmosphere system is approximately 30 percent, most of which is due to backscatter from clouds in the atmosphere. Source...
  235. Concept that the Earth's crust is composed of rigid plates that move over a less rigid interior. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  236. A satellite that can carry instruments. See bus. The same term is applied to automatic weather data transmitters installed on buoys, balloons, ships, and planes, and mounted in remote areas. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  237. An orbit with an orbital inclination of near 90 degrees where the satellite ground track will cross both polar regions once during each orbit. The term is used to describe the near-polar orbits of spacecraft such as the USA's NOAA/TIROS and Landsat...
  238. Strictly, too much of any substance in the wrong place or at the wrong time is a pollutant. More specifically, atmospheric pollution may be defined as the presence of substances in the atmosphere, resulting from man-made activities or from natural...
  239. The comparatively slow torquing of the orbital planes of all satellites with respect to the Earth's axis, due to the bulge of the Earth at the equator which distorts the Earth's gravitational field. Precession is manifest by the slow rotation of the...
  240. Moisture that falls from clouds. Although clouds appear to float in the sky, they are always falling, their water droplets slowly being pulled down by gravity. Because their water droplets are so small and light, it can take 21 days to fall 1,000...
  241. The knowledge and capacities developed by governments, professional response and recovery organizations, communities and individuals to effectively anticipate, respond to, and recover from, the impacts of likely, imminent or current hazard events or...
  242. The outright avoidance of adverse impacts of hazards and related disasters. Comment: Prevention (i.e. disaster prevention) expresses the concept and intention to completely avoid potential adverse impacts through action taken in advance. Examples of...
  243. R&D
    Research and Development. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  244. The study of interference patterns caused by radar signals; a technique that enables scientists to generate three dimensional images of the Earth's surface. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  245. 1. In optics, the point or object from which light proceeds. 2. In geometry, a straight line proceeding from a given point, or fixed pole, about which it is conceived to revolve. 3. In astronomy, the point in the heavens from which a shower of...
  246. Energy transfer in the form of electromagnetic waves or particles that release energy when absorbed by an object. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  247. A change in the balance between incoming solar radiation and outgoing infra-red radiation. Without any radiative forcing, solar radiation coming to the Earth would continue to be approximately equal to the infra-red radiation emitted from the Earth...
  248. Theory dealing with the propagation of electromagnetic radiation through a medium. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  249. The complete range of frequencies or wave lengths of electromagnetic waves, specifically those used in radio and television. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  250. An electrical impulse sent through the atmosphere at radio frequency. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  251. Giving off or capable of giving off radiant energy in the form of particles or rays, as in alpha, beta, and gamma rays. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  252. An instrument that quantitatively measures electromagnetic radiation. Weather satellites carry radiometers to measure radiation from snow, ice, clouds, bodies of water, the Earth's surface, and the sun. Source: NASA (http://earthobservatory.nasa.gov...
  253. A balloon-borne instrument that measures meteorological parameters from the Earth's surface up to 20 miles in the atmosphere. The radiosonde measures temperature, pressure, and humidity, and transmits or 'radios' these data back to Earth. Upper air...
  254. An evergreen woodland of the tropics distinguished by a continuous leaf canopy and an average rainfall of about 100 inches per year. Rain forests play an important role in the global environment. The Earth sustains life because of critical balances...
  255. Calibrated container that measures the amount of rainfall during a specific period of time. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  256. As it happens. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  257. Actions taken to reestablish a community after a period of rehabilitation subsequent to a disaster. Actions would include construction of permanent housing, full restoration of all services, and complete resumption of the pre-disaster state.
  258. The restoration, and improvement where appropriate, of facilities, livelihoods and living conditions of disaster-affected communities, including efforts to reduce disaster risk factors. The recovery phase begins soon after the response and...
  259. The return of light or sound waves from a surface. If a reflecting surface is plane, the angle of reflection of a light ray is the same as the angle of incidence. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  260. The operations and decisions taken after a disaster with a view to restoring a stricken community to its former living conditions, in particular with a view to restoring life lines and key services.
  261. The ratio of the amount of water vapor in the air compared to the amount required for saturation (at a particular temperature and pressure). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  262. he technology of acquiring data and information about an object or phenomena by a device that is not in physical contact with it. In other words, remote sensing refers to gathering information about the Earth and its environment from a distance, a...
  263. The ability of a system, community or society exposed to hazards to resist, absorb, accommodate to and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic...
  264. A measure of the ability to separate observable quantities. In the case of imagery, it describes the area represented by each pixel of an image. The smaller the area represented by a pixel, the more accurate and detailed the image. Source: NASA (...
  265. The provision of emergency services and public assistance during or immediately after a disaster in order to save lives, to reduce health impacts, to ensure public safety and to meet the basic subsistence needs of the people affected.
  266. An east-to-west orbit of Earth (Earth spins west to east). See prograde orbit. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  267. Process of the Earth circling the sun in its orbit. Revolution determines the seasons, and the length of the year. In addition, differences in seasons occur because of Earth's inclination (tilt on its axis) of about 23.5 degrees as it revolves...
  268. Process of the Earth turning on its axis. Rotation determines day and night, and the length of the day. Compare with revolution. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  269. A nominal frequency range from 4 to 2 GHz (7 to 20 cm wavelength) within the microwave (radar) portion of the electromagnetic spectrum. S-band radars are used for medium-range meteorological applications, for example rainfall measurements, as well...
  270. The degree of salt in water. The rise in sea level due to global warming would result in increased salinity of rivers, bays and aquifers. This would affect drinking water, agriculture and wildlife. Source: NASA (http://earthobservatory.nasa.gov/...
  271. The process of obtaining a sequence of discrete digital values from a continuous sequence of analog data. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  272. A free-flying object that orbits the Earth, another planet, or the sun. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  273. In telecommunications, the use of artificial satellites to provide communication links between various points on Earth.(source: Encyclopedia Britannica) Satellite communications play a vital role in the global telecommunications system....
  274. The time from one perigee (the point of an elliptical orbit path where a satellite is closest to Earth) to the next. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  275. An imaging system consisting of lenses, moving mirrors, and solid-state image sensors used to obtain observations of the Earth and its atmosphere. Scanning radiometers, which are the sole imaging systems on all current operational weather satellites...
  276. The process by which electromagnetic radiation interacts with and is redirected by the molecules of the atmosphere, ocean, or land surface. The term is frequently applied to the interaction of the atmosphere on sunlight, which causes the sky to...
  277. A high-frequency radar instrument that transmits pulses of energy towards the ocean and measures the backscatter from the ocean surface. It detects wind speed and direction over the oceans by analyzing the backscatter from the small wind-induced...
  278. Object space illuminated by a sensor. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  279. The height of sea ice from the keel (the lowest point underwater) to the ridge (the highest point above water). http://earthobservatory.nasa.gov/Features/ClimateClues/Images/diagram.gi... Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  280. The datum against which land elevation and sea depth are measured. Mean sea level is the average of high and low tides. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  281. The temperature of the layer of seawater (approximately 0.5 m deep) nearest the atmosphere. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  282. The excess radiative energy that has passed from the Earth's surface to the atmosphere through advection, conduction, and convection processes. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  283. Device that produces an output (usually electrical) in response to stimulus such as incident radiation. Sensors aboard satellites obtain information about features and objects on Earth by detecting radiation reflected or emitted in different bands...
  284. The relationship between input and output for a given measurement. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  285. The radiation received from the sun and emitted in the spectral wavelengths less than 4 microns. It is also called 'solar radiation'. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  286. Energy received from the sun is solar radiation. The energy comes in many forms, such as visible light (that which we can see with our eyes). Other forms of radiation include radio waves, heat (infrared), ultraviolet waves, and x-rays. These forms...
  287. A special kind of radiometer that measures changes in atmospheric temperature with height, as well as the content of various chemical species in the atmosphere at various levels. The High Resolution Infrared Radiation Sounder (HIRS), found on NOAA...
  288. The set of agencies, organizations and institutions at local, national, regional and international levels that focus their activities on the design, launch, deployment and operation of satellites, space-stations and probes.
  289. Information that is derived from the data which is collected through sensors in satellites When we talk about space-based information, we refer to the information that can be derived using Earth Observation, GNSS and satellite communications.
  290. A characteristic that refers to a location (which may be a specific location on the Earth's surface, or relative to an arbitrary point). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  291. A finite segment of wavelengths in the electromagnetic spectrum. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  292. This refers to the particular form or shape evinced by the power spectrum calculated from the data comprising the time series of a process. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  293. A device for measuring the relative amounts of radiant energy or radiant flux as a function of wavelength. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  294. 1. The series of colored bands diffracted and arranged in the order of their respective wave lengths by the passage of white light through a prism or other diffracting medium and shading continuously from red (produced by the longest visible wave)...
  295. Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles to 15 km at the equator and an upper boundary of approximately 50 km. Depending upon latitude and season, the temperature in...
  296. Point where a straight line drawn from a satellite to the center of the Earth intersects the Earth's surface. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  297. Describes the orbit of a satellite that provides consistent lighting of the Earth-scan view. The satellite passes the equator and each latitude at the same time each day. For example, a satellite's sun-synchronous orbit might cross the equator...
  298. The temperature of the air near the surface of the Earth, usually determined by a thermometer in an instrument shelter about 2 m above the ground. The true daily mean, obtained from a thermograph, is approximated by the mean of 24 hourly readings...
  299. The area observed by a satellite as it orbits the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  300. The ability to see large areas at the same time. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  301. A high-resolution ground-mapping technique that effectively synthesizes a large receiving antenna by processing the phase of the reflected radar return. The along-track resolution is obtained by timing the radar return (time-gating) as for ordinary...
  302. A space-to-ground data stream of measured values (including instrument science data, instrument engineering data, and spacecraft engineering data) that does not include command, tracking, computer memory transfer, audio, or video signals. Source:...
  303. A measure of the energy in a substance. The more heat energy in the substance, the higher the temperature. The Earth receives only one two-billionth of the energy the sun produces. Much of the energy that hits the Earth is reflected back into space...
  304. A characteristic that refers to the time at which a given data set was acquired. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  305. The total infrared radiation emitted by the Earth and its atmosphere in the temperature range of approximately 200-300K. Because the Earth is nearly a perfect radiator, the radiation from its surface varies as the fourth power of the surface's...
  306. Expression that groups the three communities that UN-SPIDER has to bridge
  307. Of, making use of, producing, or caused by heat. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  308. Electromagnetic radiation with wavelengths between about 3 and 25 micrometers. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  309. Local storm resulting from warm humid air rising in an unstable environment. Air may start moving upward because of unequal surface heating, the lifting of warm air along a frontal zone, or diverging upper-level winds (these diverging winds draw air...
  310. The technique of graphically representing the exact physical features of a place or region on a map. The physical features of a place or region. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  311. A twisting, spinning funnel of low pressure air. The most unpredictable weather event, tornadoes are created during powerful thunderstorms. As a column of warm air rises, air rushes in at ground level and begins to spin. If the storm gathers energy...
  312. The amount of solar energy hitting the top of the Earth’s atmosphere, currently accepted to be about 1,368 watts per square meter. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  313. Any one of the less common gases found in the Earth's atmosphere. Nitrogen, oxygen, and argon make up more than 99 percent of the Earth's atmosphere. Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone, and ammonia,...
  314. Tracking and Data Relay Satellite System (TDRSS) An orbiting communications satellite, developed by NASA, used to relay data from satellite sensors to ground stations and to track the satellites in orbit. Source: NASA (http://earthobservatory.nasa....
  315. The process in plants by which water is taken up by the roots and released as water vapor by the leaves. The term can also be applied to the quantity of water thus dissipated. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  316. Tropical storms generally form in the eastern portion of tropical oceans and track westward. Hurricanes, typhoons, and willy-willies all start out as weak low pressure areas that form over warm tropical waters (e.g., surface water temperature of at...
  317. The lower atmosphere, to a height of 8-15 km above Earth, where temperature generally decreases with altitude, clouds form, precipitation occurs, and convection currents are active. See atmosphere. Source: NASA (http://earthobservatory.nasa.gov/...
  318. Ozone that is located in the troposphere and plays a significant role in the greenhouse gas effect and urban smog. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  319. Hurricanes in the Western Pacific Ocean. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  320. The energy range just beyond the violet end of the visible spectrum. Although ultraviolet radiation constitutes only about 5 percent of the total energy emitted from the sun, it is the major energy source for the stratosphere and mesosphere, playing...
  321. United Nations Economic Commission for Europe
  322. United Nations Environment Programme
  323. The United Nations Office for Disaster Risk Reduction
  324. United Nations Office at Geneva
  325. UNITAR's Operational Satellite Applications Programme
  326. USG
    Under-Secretary General
  327. United States Geological Survey
  328. Comparing a climate model's predictions with observations of the real climate, in order to test the reliability and accuracy of the model. The most obvious way to test a climate model is to use it to analyze past events, and then see whether its...
  329. A physical quantity that has both a magnitude and a direction and that adds like displacement; velocity, acceleration, and force are prime examples. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  330. A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent, sometimes with other animals serving as intermediary hosts. The transmission depends...
  331. That part of the electromagnetic spectrum to which the human eye is sensitive, between about 0.4 and 0.7 micrometers. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  332. A naturally occurring vent or fissure at the Earth's surface through which erupt molten, solid, and gaseous materials. Volcanic eruptions inject large quantities of dust, gas, and aerosols into the atmosphere. A major component of volcanic clouds is...
  333. The characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard.
  334. World Conference on Disaster Risk Reduction
  335. WHO
    World Health Organisation
  336. WIA
    Women in Aerospace
  337. Term used to denote a region of the electromagnetic spectrum where the atmosphere does not absorb radiation strongly. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  338. A nominal frequency range from 12.5 to 8 GHz (2.4 to 3.75 cm wavelength) within the microwave (radar) portion of the electromagnetic spectrum. X-band is a suitable frequency for several high-resolution radar applications and has often been used for...
  339. Short electromagnetic waves whose wavelengths range from .00001 to 3000 angstroms. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  340. Animal plankton. Small herbivores that float or drift near the surface of aquatic systems and that feed on plant plankton (phytoplankton and nanoplankton). Source: NASA (http://earthobservatory.nasa.gov/Glossary)