List of Terms
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

  • Abiotic environment - The nonliving physical and chemical environment that exerts an influence on living organisms: for example soil, water, air
  • Adaptation - Adjusting to changes in climate and their consequences
  • Abundance - How common an element, molecule, or isotope is within a given space, often relative to other elements, molecules, or isotopes
  • Aerobic - Requiring molecular oxygen (O2) for life or activity: taking place in the presence of oxygen
  • Aerosol - In atmospheric chemistry, a fine particle (soot, dust, ash) suspended in a liquid
  • Air Pressure - Pressure exerted by the atmosphere
  • Air Quality - How clean or dirty the air is because of emissions during a period of measurement
  • Albedo - A measure of the amount of solar radiation reflected by an object. Clouds reflect solar energy back into space as visible light. On the Earth's surface, light colored land (snow, deserts, ice fields)reflect solar energy back to space as infrared (IR) The whole Earth's albedo is about 30 percent: the albedo of snow about 90 percent and the albedo of water about 10 percent.
  • Algae - Primitive water-dwelling plants with a one-celled or simple multicellular structure. Algae lack roots. Stems or leaves but usually contain chlorophyll. They include kelps and seaweed, and phytoplankton such as the diatoms.
  • Anaerobic - Living or active in the absence of oxygen
  • Anemometer - An instrument for measuring and indicating the force or speed of the wind
  • Anthropogenic - Derived from human activities
  • Atmosphere: - The mixture of gases that surrounds the Earth and is held to it by gravity: it is one of the five main parts of the Earth system
  • Atmospheric dynamics - The forces that create and maintain motion and are associated with the heat transformations in the atmosphere:


  • Barometer: - An instrument used to measure atmospheric pressure; pressure can be measured using water, air, or mercury
  • Baseline Observatory - An atmospheric observatory located far from pollution sources where continuous in-situ (in place) atmospheric measurements are being made, and/or frequent air samples are being taken for analysis in a laboratory
  • Bathymetry - The measurement of water depths at various places in a body of water
  • Biomass - Any organic material (living or dead)
  • Biome - A major type of land community of organisms, usually identified in terms of characteristic vegetation; for example, tropical rain forest or desert.
  • Biosphere - The community of all living organisms and the parts of the solid earth, oceans, and atmosphere on which they depend
  • Biota - All of the plant and animal life in a given area
  • Biotic - Having to do with living organisms
  • Boiling Point - The temperature at which a liquid boils at a fixed pressure
  • Budget - A balance sheet of all the sources and sinks for a particular substance in a single reservoir


  • Carbon - An abundant, nonmetallic element that forms the backbone of organic molecules which are the building blocks for all life; has an atomic number of 6; there are 3 naturally occurring isotopes: carbon-12, carbon-13, and carbon-14
  • Carbonation The process in which carbonic acid (H2CO3) reacts chemically with other substances
  • Carbon cycle - The continuous exchange and recycling of carbon through the Earth system, from the atmosphere (mostly CO2, but also other carbon containing gases) to the biosphere (wood, biomass), to the oceans (bicarbonate ions, a component of sea salt), from fossil fuels, and to carbonate rock such as limestone and marble
  • Carbon Cycle Greenhouse Gases (CCGG) Group - Part of the Global Monitoring Division of NOAA’s Earth System Research Laboratory that is primarily focused on monitoring and understanding the earth’s carbon cycle
  • Carbon sinks - Locations in the biosphere where excess carbon is stored (e.g long lived trees, limestone, fossil fuels)
  • Carbon Dioxide (CO2) - A colorless, odorless gas consisting of molecules made up of two oxygen atoms and one carbon atom, produced by numerous processes, including respiration and burning of carbon-based fuels. It is the principal greenhouse gas in the Earth's atmosphere after water vapor
  • Carbon dioxide fertilization effect - The increase in plant photosynthesis and/or growth that may occur in the presence of increased levels of CO2 in the atmosphere.
  • Carbon Monoxide (CO) - A colorless, odorless, and toxic gas consisting of molecules of one oxygen atom and one carbon atom; results from inefficient combustion or chemical reactions occurring in the atmosphere
  • Carbonic Acid - A weak acid created by the dissolution of carbon dioxide into water, has a chemical formula of H2CO3
  • CarbonTracker - A computer model that calculates carbon dioxide uptake and release at the Earth’s surface over time in such a way that they are consistent with a global set of observations of the CO2 abundance in the atmosphere
  • Celsius (C) - Temperature scale named after Anders Celsius, a Swedish Astronomer; states that ice melts at 0° C and water boils at 100° C; absolute zero is at -273.15°C (MW, W)
    C to F: °C= (°F-32) x 5/9
    C to K: °C= K-273.15
  • Chemical formula - A combination of chemical symbols used to represent compounds
  • Chlorofluorocarbons (CFCs) - A family of chemicals used in a variety of industrial products. One of the major greenhouse gases in the Earth's atmosphere, and also the leading cause of ozone depletion.
  • Chlorophyll - The organic green pigment molecule, occurring in plants, that captures light energy and channels it into the photosynthetic process.
  • Climate - Meteorological conditions including temperature, precipitation, and wind, averaged over a long period, which characteristically prevail in a particular region during a specific month, season, or entire year. It is a complex environmental system, involving interactions among the atmosphere, oceans, land, ice, plants, animals (including humans) and energy from the Sun. over a long period, which characteristically prevail in a particular
  • Climate Change - A significant and lasting change to the state of the climate in a given area; typically this change occurs gradually due to natural variations, but change may also be forced more rapidly due to human activities which alter the composition of the atmosphere, the land surface, or ecosystems; although often used interchangeably with the term “global warming,” climate change can refer to other changes (e.g. changes in precipitation) in addition to rising temperatures
  • Climate models - Computerized representations of the factors that control climate. They use the laws of physics to predict what could happen to the climate given any situation, such as a change in the amount of carbon dioxide in the atmosphere.
  • Clouds - A visible body of very fine water droplets or ice particles suspended in the atmosphere
  • CO2 Weather - A loose term referring to the movement of air masses with high- or low-concentrations of CO2 across a continental-scale region; these atmospheric CO2 patterns are caused by sources and sinks at the surface, and change with the winds, following weather dynamics before slowly fading through gradual mixing of air masses
  • Concentration - The amount of a substance in a defined volume of space
  • Condensation - The process by which a gas or vapor changes to a liquid; second step in the water cycle;
  • Conduction - The process by which heat is transmitted through contact with neighboring molecules
  • Convection - Large scale motion caused by density differences; for example, in the atmosphere, air that is warmed at the surface expands, making it less dense--it then rises through the surrounding colder air as a large 'bubble', moving heat and water vapor to higher altitudes
  • Convection current - A process of rapid heat transfer through a liquid in which hot bubbles of material from the bottom rise because of their lesser density, while cooler surface materials sink because of higher density
  • Convergence Zone - An area where the horizontal wind produces a net inflow of air; when there is too much air coming into the zone, the air will start to lift vertically
  • Cooperative Global Air Sampling Network - A global observing system which collects air samples on a regular basis, part of NOAA’s Earth System Research Laboratory
  • Cooling Degree Days - Days that are cooler then the mean daily average; found by subtracting 65° F from the mean daily average
  • Cold Front - The leading edge of a relatively colder air mass which separates two air masses in which the gradients of temperature and moisture are maximized. In the northern hemisphere winds ahead of the front will be typically southwest and shift into the northwest with frontal passage.
  • Conservation - The wise use of natural resources so they will not be used up too rapidly
  • Coriolis force - The deflecting effect of the Earth's rotation whereby moving-air masses in the northern hemisphere are deflected to the right and to the left in the southern hemisphere, relative to an observer on the Earth's surface
  • Cryosphere - The frozen portion of Earth's surface; one of the five main regimes of the environment
  • Cycle - An interval of time during which a sequence of a recurring succession of events or phenomena is complete; Le. the water cycle


  • Decomposition - The process of break-down that occurs after the death of living organisms, also called rotting or decay
  • Deforestation - The temporary or permanent clearance of forest for agriculture or other purposes.
  • Desertification - The process by which grasslands become deserts as a result of erosion caused by overgrazing
  • Developed country - A nation that has a high degree of industrialization and a relatively high level of wealth, usually expressed by a high average income per person.
  • Developing country - A nation that has a relatively low level of industrialization and relatively low level of wealth, usually expressed by a low average income per person.
  • Dew Point - A measure of atmospheric moisture. It is the temperature to which air must be cooled in order to reach saturation (with constant air pressure and moisture content)
  • Diurnal (cycle) - Daily; related to actions which are completed in the course of a calendar day, and which typically recur every calendar day
  • Doppler effect - The apparent change in the wavelength of light that occurs when an object is moving toward or away from the Earth
  • Downdraft - A small-scale column of air that rapidly sinks toward the ground, usually accompanied by precipitation as in a shower or thunderstorm
  • Dry Line - Boundary separating moist and dry air masses; usually lies north-south; severe and sometimes tornadic thunderstorms often develop along a dry line or in the moist air just to the east of it, especially when it begins moving eastward


  • Earth System - A name describing the earth as a system of interacting and interdependent components, including atmosphere (air), biosphere (life), hydrosphere (water), and lithosphere (stone)
  • Earthquake: - A sudden movement of the earth's crust caused by the release of stress accumulated within the earth’s crust
  • Eclipse: - The partial or complete obscuring, relative to a designated observer, of one celestial body by another
  • Electromagnetic spectrum - The range of different types of radiation as characterized by wavelength and level of energy; in order of increasing wavelength (corresponding to decreasing energy content): X-rays, ultraviolet, visible light, infrared, microwaves, radio waves
  • El Nino: - An oscillation of the ocean-atmosphere system in the tropical Pacific having important consequences for weather throughout the globe; unusually warm water in the eastern Pacific ocean caused by a lowering of the thermocline; the opposite of La Nina
  • El Niño/ Southern Oscillation (ENSO): - The Southern Oscillation refers to the ocean surface pressure differences between Tahiti and Darwin, Australia. When the pressure is higher in Darwin, El Nino is occurring. El Nino is the warm episode of ENSO, while La Nina is the cool episode of ENSO.
  • Emissions: - Substances discharged into the air (usually by a smokestack or automobile engine)
  • Enhanced Fujita scale (EF): - This is an update to the Fujita scale that was released in 2007.
    EF Number 3 Second Gust (mph)Damage
    0 65-85 light
    1 86-110 moderate
    2 111-135 considerable
    3 136-165 severe
    4 166-200 devastating
    5 Over 200 catastrophic
  • Enhanced greenhouse effect - The amplified Greenhouse Effect due to human activities that increase the concentration of Greenhouse Gases within Earth’s atmosphere
  • Environment: - The complex of physical, chemical, and biotic factors (as climate, soil, and living things) that act upon an organism or an ecological community and ultimately determine its form and survival
  • Environmental system - The connections and interactions among all parts of the physical and biological environment: air (the atmosphere), water (the hydrosphere), soils and rocks (the lithosphere), and plants and animals (the biosphere).
  • Evaporation: - To convert or change into a vapor
  • Exosphere: - The most outer layer of the atmosphere


  • Fahrenheit - Temperature scale named for German physicist Daniel Gabriel Fahrenheit; at standard atmospheric pressure, the freezing point of water is at 32° and the boiling point of water is at 212°; absolute zero is at -459.67°F
    F to C: °F= °C x 5/9 +32
    F to K: °F = K x 9/5 -459.67
  • Feedback - The return of a portion of the output of any process or system to the input. The return may either add to the initial input (positive feedback) or subtract from the initial input (negative feedback).
  • Flux - The amount of mass flowing between two places, which can be in one direction or in both directions; for example, CO2 from the atmosphere entering the ocean, and vice versa; also often used in engineering to describe the rate of flow of liquid or gas through pipes
  • Fossil - An impression, cast, outline, track or body part of any animal or plant that is preserved in rock after the original organic material is transformed or removed
  • Fossil fuels - Carbon-containing fuels, including coal, oil, and natural gas, that formed over hundreds of millions of years from the remains of living organisms
  • Freezing Point - The temperature point at which a liquid turns to its solid state from its liquid state
  • Front - A boundary or transition zone between two air masses of different density, and thus (usually) of different temperature. A moving front is named according to the advancing air mass.
  • Fujita Scale - A scale of wind damage intensity in which wind speeds are inferred from an analysis of wind damage:
    Number Wind Speed (mph)Damage
    F0 (weak): 40- 72 mph, light damage.
    F1 (weak): 73-112 mph, moderate damage.
    F2 (strong): 113-157 mph, considerable damage.
    F3 (strong): 158-206 mph, severe damage.
    F4 (violent): 207-260 mph, devastating damage.
    F5 (violent): 261-318 mph, (rare) incredible damage.


  • Gamma Rays - In the light spectrum, gamma rays are the highest level of energy and thus have the shortest wave lengths
  • General Circulation Model (GCM) - A computer model which mathematically describes. large-scale global circulation of the atmosphere, based on a number of physics principals
  • Geosphere: - The solid part of the earth consisting of the crust and outer mantle
  • Geosynchronous orbit - An orbit in which a satellite's rate of revolution exactly matches the Earth's rate of revolution; geostationary
  • Geothermal energy - Energy produced from the heat within the Earth
  • Global Warming - The observation that the atmosphere near the earth’s surface is warming; one of the many kinds of climate change;
  • GLOBALVIEW - A compilation of atmospheric greenhouse gas measurements, used to help understand and visualize greenhouse gas distributions (in both space and time)
  • Greenwich Mean Time (GMT) - A term originally referring to mean solar time at the Royal Observatory in Greenwich, London; regularly referred to Coordinated Universal Time (UTC) when this is referred to as a time zone; UTC is an atomic time scale that approximates GMT to within a second
  • Greenhouse Effect - A process which warms the earth’s atmosphere due to the absorption of radiation energy by several trace gases; these greenhouse gases allow solar radiation to reach the earth’s surface but then absorb the energy as it is reemitted as infrared radiation, acting to contain the heat within the atmosphere; this occurs naturally and is increased by humans (see Enhanced Greenhouse Effect)
  • Green House Gases (GHGs) - Gases in the atmosphere that contribute to the Greenhouse Effect due to properties which absorb and emit infrared radiation. In Earth's atmosphere, these gases include water vapor, carbon dioxide, water vapor, methane, nitrous oxide and chlorofluorocarbons (CFCs).


  • Heating Degree Days - Days that are warmer than the mean daily average; found by subtracting the mean daily temperature from 65° F
  • Homeostasis - The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes
  • Humidity - The amount of water suspended in the air in tiny droplets
  • Humus - Part of the soil formed by decaying organic material
  • Hurricane - Tropical cyclone in a low pressure system that is accompanied by thunderstorms and counterclockwise circulation (FEMA)
  • Hydrocarbon - Substance containing the elements carbon and hydrogen
  • Hydroelectric power - The use of mechanical energy of falling or running water to generate electricity
  • Hydrologic Cycle - The sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration
  • Hydrosphere - The water portion of the Earth (oceans, lakes, rivers, etc;) one of the five main regimes of the Earth environment


  • Industrial Revolution - The transformation which occurred first in many Western countries, including the United States, in the 1800s, characterized by coal burning, steel making, mass production, and rapid technical advances; marked as the beginning of strong increases in fossil fuel use
  • Interactive Atmospheric Data Visualization (IADV) - A web-based data exploration tool for the atmospheric trace gases measured by NOAA’s Carbon Cycle Greenhouse Gases Group
  • Index fossil - The fossil of an organism that existed on Earth for only a short time and that can be used by scientists to determine the relative age of rock
  • Infrared Radiation - Electromagnetic radiation that has a wavelength just greater than that of red light but less than that of microwaves, emitted particularly by heated objects
  • Inorganic - Not formed from living things or the remains of living things
  • Interglacial - The time period between major glaciations, or ice ages
  • Inter-Tropical Convergence Zone (ITCZ) - Appears as a band of clouds, usually thunderstorms, that circle the globe near the equator. The position of the ITCZ varies seasonally: it moves north in the northern summer and south in the northern winter and is responsible for the wet and dry seasons in the tropics. Right at the equator there are 2 wet seasons and 2 dry seasons, while away from the equator there are only one of each. ITCZ exists because of the convergence of the trade winds since in the northern hemisphere the trade winds go towards the south, while in the southern hemisphere the trade winds go north.
  • Inversion - A departure from the usual increase or decrease in an atmospheric property with altitude
  • Ion - An electrically charged atom, molecular constituent or group of atoms: e.g. Na+, Al3+, Cl-, NH4+
  • Ionosphere - The part of the atmosphere between 80 and 550 km above the Earth's surface
  • Isobar - A line connecting points of equal pressure
  • Isotherm - A line on a weather map that connects locations with the same temperature
  • Isotope - Atoms of the same element, but with different masses; the number of protons and electrons are the same, but the number of neutrons differ; isotopes of an element all react chemically in the same way, but the rate of reaction is slightly different, resulting in isotopic fractionation
  • Isotopic fractionation - A change in isotopic ratio during a reaction or physical process (such as evaporation or freezing); for example, when CO2 is photosynthesized by plants, fractionation occurs, so that the carbon-12 to carbon-13 isotopic ratio of the carbon taken into the plant is different than that in atmospheric CO2
  • Isotopic ratio - The ratio of two different isotopes of a single element in a mixture; usually measured in units of permil (‰); certain materials have characteristic isotopic ratios that can be used to identify the source


  • Jet Stream - Relatively strong winds concentrated in a narrow stream in the atmosphere, normally referring to horizontal, high-altitude winds; position and orientation of jet streams vary from day to day; general weather patterns are closely related to the jet stream position


  • Kelvin (K) - Scale to measure temperature named after Lord William Thomson, Baron Kelvin of Largs, Lord Kelvin of Scotland, a British mathematician and physicist; one of the SI base units; absolute zero is at 0K
    K to F: K = (°F + 469.67) x 5/9
    K to C: K = °C + 273.15


  • La Niña - Unusually cold ocean temperatures in the tropical Pacific caused by a raised thermocline; opposite of El Nino
  • Latitude - Angular distance north or south from the earth's equator measured through 90 degrees
  • Light - Electromagnetic radiation that can produce a visual sensation
  • Lithosphere - The rigid outer part of the earth, consisting of the crust and upper mantle
  • Longitude - The arc or portion of the earth's equator intersected between the meridian of a given place and the prime meridian and expressed either in degrees or in time
  • Longwave radiation - The heat energy emitted by the Earth which is also known as infrared radiation. This heat can be trapped by the atmosphere, which helps keep the planet warm.


  • Magnetosphere - The area around the Earth that extends beyond the atmosphere, in which the Earth's magnetic force operates
  • Major glaciation - A period in Earth history when large parts of the Earth's surface were covered with sheets of ice: an ice age
  • Marine Biosphere - The community of all organisms living in the oceans and the oceans on which they depend
  • Melting Point - The temperature at which a solid becomes a liquid at standard atmospheric pressure
  • Mesopause - A small (~2km) layer between the mesosphere and the thermosphere
  • Mesosphere - The layer of the atmosphere between the stratosphere and the thermosphere; temperature decreases with height (jet Stream)
  • Meteorology - The science that deals with the phenomena of the atmosphere, especially weather and weather conditions
  • Methane (CH4) - A colorless, odorless, flammable, non-toxic consisting of molecules made up of four hydrogen atoms and one carbon atom; it is the main constituent of natural gas; is released in environments in which organic matter decomposes without enough oxygen. It is one of the major greenhouse gases in Earth's atmosphere.
  • μmol mol-1, or micromol mol-1 - A unit of concentration used to express the abundance of certain trace gases within the atmosphere; micro is one millionth, so μmol mol-1 is also called parts per million (ppm); For example, 401 ppm of CO2 means that in every 1,000,000 molecules of air (including CO2 itself) there are on average 401 molecules of CO2
  • Mixing ratio - The percentage of elements in a unit of air or in a unit of solution
  • Molecule - The smallest particle of a pure substance (element or compound) that can exist and still retain the physical and chemical properties of the substance


  • Nanometer - A unit of length equal to one-billionth of a meter (10-9 meters)
  • Natural resource - Any material removed from the Earth and used by people
  • Nebula - A massive cloud of dust and gas between stars; the solar system is thought to have formed from a nebula, which later condensed to form the Sun and 9 planets (Nebular Theory)
  • Net primary production (NPP) - Organic matter accumulation in plants, calculated as the difference between photosynthesis and respiration
  • Nitrous oxide (N2O) - A colorless, non-flammable gas consisting of molecules made up of two nitrogen atoms and one oxygen atom; commonly called "laughing gas,· produced by a variety of processes; it is a major greenhouse gas in the Earth's atmosphere.
  • Nonrenewable resource - Any resource that cannot be replaced by nature, such as fossil fuels and minerals
  • Nuclear energy - Energy locked within the nucleus (center) of an atom
  • Nuclear fission - The splitting of an atomic nucleus into two smaller nuclei, during which nuclear energy is released
  • Nuclear fusion - The combining of two atomic nuclei to produce one larger nucleus, with the release of nuclear energy


  • Oceanography - The branch of science concerned with the physical and biological properties and phenomena of the sea
  • Organic Matter/Organic Material: - Anything living or derived from living things, including the dead remains; containing the long chains of carbon atoms characteristic of living things.
  • Organic substance - Chain- or ring-like carbon-containing compounds that also contain hydrogen, and can contain oxygen, nitrogen, sulfur and phosphorus
  • Outgassing - The release of gases to the atmosphere and oceans by volcanism
  • Oxidant - A reactive chemical compound that tends to lose electrons when it interacts with other molecules; in the atmosphere important oxidants are ozone (O3 ) and hydroxyl radical (OH)
  • Oxidation - The process in which oxygen chemically combines with another substance, often resulting in the breakdown of materials (i.e. rust)
  • Oxygen: - An abundant, nonmetallic element that has an atomic number of 8; gaseous oxygen is a colorless, odorless molecule consisting of two oxygen atoms that comprises 21% of Earth’s atmosphere.
  • Ozone (O3) - A molecule that has three atoms of oxygen. Found in the stratosphere where it shields the surface of the Earth from incoming UV radiation, and in the troposphere is major component of pollution
  • Ozone hole - A reduction in the amount of ozone detected in Earth's upper atmosphere. The ozone layer protects Earth's surface from harmful ultraviolet rays emitted by the Sun.
  • Ozone Layer - A layer in the stratosphere that is below the stratopause (19-30km); prevents most of the harmful UV radiation rays from reaching the earth’s surface


  • Pangaea - The single giant landmass that existed more than 200 million years ago and gave rise to the present day continents
  • Parts per million (ppm) - A unit that expresses the concentration of a chemical substance; a 1 ppm concentration of molecule X means that one molecule out of a million is molecule X. Related units are parts per billion (ppb) and parts per trillion (ppt). See also μmol mol-1.
  • Peat - A soft substance made of decayed plant fibers; first stage in the development of coal
  • Permafrost - The permanently frozen layer of soil on a tundra; contains large amounts of sequestered methane
  • pH - A numerical scale that indicates the acidity of a substance; neutrality is indicated by pH 7; higher pH values are basic, and lower pH values are acidic
  • Photochemical reaction - Any chemical reaction that requires light (often ultraviolet light), and which often yields a secondary pollutant
  • Photon - An observable quantity of electromagnetic energy;
  • Photorespiration - Plant respiration that occurs in the presence of light; it wastes energy that could otherwise be used to make photosynthetic products; common in Ca plants in bright sunlight on hot days;
  • Photosynthesis - The process by which light, water and carbon dioxide are used by plants to makes carbohydrate products (sugars), essentially converting light into chemical energy and releasing oxygen into the atmosphere; also called primary production
  • Phytoplankton - Tiny photosynthetic plants that live in the water column of oceans and lakes: form the basis of the aquatic food chain
  • Polarity - The property of a molecule with oppositely charged ends (poles)
  • Pollution - The release into the environment of substances that change the environment for the worst
  • Population - All members of a particular species in a given area at one time
  • Precipitation - The process by which water returns to the Earth in the form of rain, snow, sleet or hail; third step in the water cycle
  • Pre-industrial era - The period in world history between about 1750 and 1800; prior to the Industrial revolution
  • Pressure: - Force applied uniformly over a surface, measured as force per unit of area


  • Radiation - Energy emitted as electromagnetic waves or subatomic particles
  • Radiation Budget - The accounting of radiation which enters and leaves Earth’s atmosphere.
  • Red shift - The shift toward the red end of the spectrum of a star that is moving away from the Earth
  • Relative Humidity - A dimensionless ratio, expressed in percent, of the amount of atmospheric moisture present relative to the amount that would be present if the air were saturated; does not directly indicate the amount of moisture in the atmosphere
  • Remote Sensing - The science of obtaining information about a subject or object without actually being in contact with that subject or object; used to detect and measure weather phenomenon with equipment that is sensitive to light, heat, and radio waves
  • Reservoir - An area within the environment defined by specific physical, chemical and/or biological characteristics that are relatively uniformly distributed In the context of the carbon cycle, the interconnected areas within the Earth System which store and exchange carbon; includes the atmosphere, the oceans, the terrestrial biosphere, and fossil fuels.
  • Ring of Fire - The earthquake and volcano zone that encircles the Pacific Ocean
  • Reactant - A starting material of a chemical reaction: reactants are shown on the left side of the arrow in a chemical equation
  • Residence time - The average time spent in a reservoir ( atmosphere, oceans, soil, etc.) by physical, chemical or biological properties that are relatively uniformly distributed
  • Respiration: - The process by which living organisms convert organic (carbon) material into energy needed for living, by taking up molecular oxygen and the releasing of carbon dioxide to the atmosphere.


  • Saffir-Simpson scale - The scale that is used to measure hurricane wind speeds and determine into which category a system falls (FEMA)
    Category Sustained Winds (MPH) Damage Storm Surge (feet)
    1 74-95 Minimal 4-5
    2 96-110 Moderate 6-8
    3 111-130 Extensive 9-12
    4 131-155 Extreme 13-18
    5 More than 155 Catastrophic more than 18
  • Salinity - The relative proportion of salt in a solution
  • Satellite - Any celestial body orbiting around a planet or star
  • Season - One of the natural periods into which the year is divided by the equinoxes and solstices or atmospheric conditions
  • Severe Thunderstorm - A thunderstorm which produces tornados, hail 0.75 inches or more in diameter, or winds of 50 knots (58 mph) or more
  • Shortwave radiation - The light energy emitted by the Sun, primarily in the ultraviolet and visible light portions of the spectrum.
  • Silicate Weathering - The erosion of rocks containing silicate minerals due to weather, ultimately removing carbon dioxide from the atmosphere over long time periods as carbonic acid in rainwater reacts with silicate rocks to create bicarbonate ions which are then carried to the oceans.
  • Sink - The receptor for material when it disappears or is removed from a reservoir. In the context of the carbon cycle, any process by which carbon dioxide is removed from the atmosphere; sinks may be natural (e.g., photosynthesis and reforestation, dissolution in ocean water) or due to human activities (e.g., managed forests and other carbon capture strategies).
  • Smog - The thick brownish haze formed when hydrocarbons, carbon monoxide, and other gases react in sunlight
  • Solar constant - The amount of solar energy intercepted by the Earth at the average Sun-Earth distance: having a value of 1380 Watts (W) m-2
  • Solar flare - A storm on the Sun that shows up as a bright burst of light on the Sun's surface
  • Solar Radiation - Energy emitted by the sun composed mostly of visible and ultraviolet light.
  • Solar wind - A continuous stream of high-energy particles released into space from the Sun's corona
  • Source - In the context of the carbon cycle, any process by which carbon dioxide is added to the atmosphere, sources may be natural (e.g., soil and plant respiration) or due to human activities (e.g., combustion of fossil fuels and deforestation).
  • Spectroscope - An instrument that breaks up light into its characteristic colors
  • Spectrum - The band of colors formed when light passes through a prism
  • Squall Line: - A solid or nearly solid line or band of active thunderstorms
  • Stomates - The tiny pores on the surface of leaves and stems, through which gases and water vapor are transferred between the atmosphere and the plant: the size of the opening depends on environmental conditions: it is crucial in controlling the amount of water lost from the interior of the plant
  • Stratopause - The transition layer between the Stratosphere and the Mesosphere
  • Stratosphere - The atmospheric layer between the troposphere and the mesosphere
  • Sublimation - Where a substance goes from a solid state to a vapor state, skipping the liquid state
  • Sulfur Hexafluoride (SF6) - An extremely potent greenhouse gas made by humans, and used mostly as an electrical insulator during high voltage transmission of electricity.
  • Sunspot - A dark area on the surface of the Sun
  • Surface runoff - Water that enters a river or stream after a heavy rain or during a spring thaw of snow or ice


  • Terrestrial Biosphere - The community of all organisms living on the land and the land surface features on which they depend.
  • Temperature - A measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale
  • Theory of Continental Drift - The theory proposed by Alfred Wegener that the continents were once joined together and have since drifted apart
  • Thermal expansion - When most substances are heated, their volume increases due to increasing vibrations in fheir component molecules. In the case of ocean thermal expansion, as the water molecules are warmed, the volume of water increases.
  • Thermal pollution - An increase in temperature caused when cold water used to cool reactors in nuclear power plants is heated and discharged into rivers and lakes
  • Thermocline - A layer in the ocean that separates the warmer, less salty water from the colder, saltier water
  • Thermosphere - The layer in the atmosphere between the Mesosphere and the Exosphere; temperature fluctuates a lot, but mostly increases with height; satellites orbit the earth in the Thermosphere
  • Thunderstorm - A rain shower that also has thunder and lightning; lightning is caused by charges in the clouds of the thunderstorm (NSSL)
  • Time Series - Measurements of a quantity collected over a period of time.
  • Topography - A map or graph that shows the varying elevations of natural and man made objects with their relative positions
  • Tornado - A violently rotating column of air in contact with the ground and extending from the base of a thunderstorm
  • Trace Gases - Gases which together make up less than 0.1% of the atmosphere.
  • Transpiration - The evaporation of water from the interior of plants or animals; In plants, the size of the stomatal opening regulates this water loss; In the case of corn, about 100 pounds of water are transpired for every pound of dried plant material (leaves, stems, grain, roots, cobs).
  • Tropopause - The upper boundary of the troposphere, usually characterized by an abrupt change in lapse rate from positive (decreasing temperature with height) to neutral or negative (temperature constant or increasing with height)
  • Troposphere - The lowest region of the atmosphere between the earth's surface and the tropopause, characterized by decreasing temperature with increasing altitude
  • Tsunami - An ocean wave produced by a sub-marine earthquake, landslide, or volcanic eruption. These waves may reach enormous dimensions and have sufficient energy to travel across entire oceans.


  • Ultraviolet (UV) Light - Shortwave radiation within the ultraviolet range of the electromagnetic spectrum; lies beyond the visible spectrum of light and contains wavelengths of approximately 100-400 nanometers; is harmful to most organisms.


  • Virga - Streaks or wisps of precipitation falling from a cloud but evaporating before reaching the ground
  • Visible Light - Radiation within the range of the electromagnetic spectrum that is visible to the human eye; wavelengths of visible light range from approximately 400-700 nanometers
  • Volcano - An opening in the earth's crust through which molten lava, ash, and gases are ejected


  • Warm Front - A front that moves in such a way that warm air replaces cold air.
  • Warning - A product issued by NWS local offices indicating that a particular weather hazard is either imminent or has been reported; a warning indicates the need to take action to protect life and property
  • Watch - An NWS product indicating that a particular hazard is possible; a watch is a recommendation for planning, preparation, and increased awareness
  • Water cycle - The continuous movement of water from the oceans and freshwater sources to the air and the land and finally back to the oceans; also called the hydrologic cycle
  • Water Vapor - Water in its gaseous state which accounts for 0-3% of the composition of the atmosphere; the most abundant greenhouse gas; humans exert no significant control over its abundance.
  • Wavelength - The horizontal distance between two consecutive crests or two consecutive troughs of a wave
  • Weather - The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity, and barometric pressure
  • Wildfire - Any free burning uncontainable wildland fire not prescribed for the area which consumes the natural fuels and spreads in response to its environment.


  • X-Rays - In the light spectrum, x-rays have the second shortest energy levels and the second shortest wavelengths; gamma rays have shorter wavelengths, while ultraviolet rays are longer than x-rays.


  • Zooplankton - Animal life, often microscopic, that drifts in oceans or lakes


CDE: Colorado Department of Education

FEMA: Federal Emergency Management Association


Jet Stream

MW: Merriam Webster Dictionary

NOAA: DOC and NOAA Local Climate Fact Sheet (in my possession)


NWS: National Weather Service

PMEL: Pacific Marine Environmental Laboratory
El Nino:
La Nina:

W: Wikipedia