Glossary

A seismic wave that travels through the interior of the earth and is not related to a boundary surface. (bgs)
a seismic wave that travels through rock (e.g., a P-wave or an S-wave (opentext physgeo)

Microscopic particle of dust, smoke or salt that allows for condensation of water vapor to water droplets in the atmosphere (PhysGeo)
Hygroscopic aerosol particles that can serve as nuclei of atmospheric cloud droplets, that is, particles on which water condenses (activates) at supersaturations typical of atmospheric cloud formation (AMS)

Fog exists if the atmospheric visibility near the Earth's surface is reduced to 1 kilometer or less. Fog can be composed of water droplets, ice crystals or smoke particles (PhysGeo)
Water droplets suspended in the atmosphere in the vicinity the earth's surface that affect visibility (AMS)
ground-level condensation caused if the dew point is reached in this part of the atmosphere by advection, evaporation, radiation or at a warm front or over ice (ItsEdu)

A bend or flexure in a rock unit or series of rock units that has been caused by crustal movements (geology.com)
when one or stacks of originally flat and planar surfaces such as sedimentary
beds become bent or curved as a result of plastic (i.e. permanent) and ductile deformation (files.ethz.ch/structuralgeology)

molten rock below the surface, either held within the crust or in the mantle. (itsEducation)
Molten rock originating from the Earth's interior (PhysGeo.net)

a seismic body wave that is characterized by deformation of the rock in the same direction that the wave is propagating (compressional vibration) (opentext physg)
The first and faster of the body waves which moves by a series of compressions and dilatations, similar to a sound wave. They can travel through both solid and liquid. (bgs)
The fastest set of earthquake vibrations - also known as P-waves. They move through the Earth in compression and expansion motions (much like sound waves move through air). Called primary because they are the first recorded at a seismograph. Primary waves are able to travel through both solids and liquids. (geology.com)

Reduction of precipitation commonly found on the leeward side of a mountain (PhysGeo)
the area on the leeward side of a mountain range which experiences drier conditions than the windward side. This is due to the air being drier as it has experienced condensation and precipitation on the windward side, plus the fact that the air will be sinking and therefore warming meaning relative humidity is falling and condensation cannot occur (ItsEdu)
A region of sharply reduced precipitation on the lee side of an orographic barrier, as compared with regions upwind of the barrier (AMS)

a seismic body wave that is characterized by deformation of the rock transverse to the direction that the wave is propagating (opentext physg)
The second arrival on a seismogram, the S wave, is slower than the P-wave. It is a shear wave and cannot travel through liquids. (bgs)

The vapor pressure of a system, at a given temperature, for which the vapor of a substance is in equilibrium with a plane surface of that substance's pure liquid or solid phase (AMS)
The vapor pressure at which the gaseous phase of a substance can coexist with the liquid or solid phase in equilibrium at a given temperature (Wiki)

may be more precisely defined as approximately tabular regions of concentrated deformation and flow across which adjacent relatively undeformed rock units are offset (Shear zones — an introduction and overview)
also sometimes called ductile faults, are intensely strained zones that separate less severely deformed units (UA Online course lecture)

Seismic waves with motion restricted to near the ground surface (Love and Rayleigh) (bgs)
A type of seismic wave that travels along Earth's surface. These are the waves that cause the most damage during an earthquake. (geology.com)

a convex-downward fold is a synform. Synclines have younger strata at the core (ethz)
a downward fold where the beds are known not to be overturned (physgeology open text)
A downward fold of sedimentary rock put under pressure by Earth movements (bgs)

a block of crust that has geological features that are distinctive from neighbouring regions, and is assumed to have been moved from elsewhere by tectonic processes (opentext physg)
is technically a tectonostratigraphic terrane, a piece of the earth's crust or lithosphere that has been accreted to the edge of one tectonic plate from another tectonic plate. (commons.wvc.edu)
Accreted terranes are the blocks of continental fragments and oceanic islands that have collided with a continent and are now permanently attached (national park service)

the resistance of a fluid to flow (geology.com)
how resistant a substance is to a change in form (itseducation)
is the quantity that describes a fluid's resistance to flow (physics handbook)

A process in which heat does not enter or leave a system. adiabatic processes are often used to model internal energy changes in rising and descending parcels of air in the atmosphere (PhysGeo.net)
change in temperature due to expansion or contraction of a parcel of air which thus change the pressure and therefore the temperature (ItsEducation)

The process of transport of an atmospheric property solely by the mass motion (velocity field) of the atmosphere (AMS)
horizontal transfer of heat by a horizontally moving air mass (ItsEdu)

All absolute isotopic ages are based on radioactive decay, a process whereby a specific atom or isotope is converted into another specific atom or isotope at a constant and known rate. (Britannica)
Radiometric dating calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element, e.g., carbon-14, or a long-life radioactive element plus its decay product, e.g., potassium-14/argon-40. The term applies to all methods of age determination based on nuclear decay of naturally occurring radioactive isotopes (nps.gov)

large body of air with shared temperature and humidity characteristics associated with its area of origin e.g. maritime or continental; tropical or polar (ItsEducation)
A body of air whose temperature and humidity characteristics remain relatively constant over a horizontal distance of hundreds to thousands of kilometers (PhysGeo.net)

is a measure of how much light that hits a surface is reflected without being absorbed (NC Climate Office)

the angle at which the Sun's rays strike the Earth's surface (PhysGeography.net)
In reference to solar energy systems: the angle a ray of sun makes with a line perpendicular to a surface (OpenEI)

Areas of sinking air which result in high pressure (UK Environmental)
a region of high atmospheric pressure relative to the surrounding air (Weatheronline)
An atmospheric pressure system consisting of an area of high pressure and outward circular surface wind flow (PhysGeo.net)

the dominant west-to-east motion of the atmosphere, centered over the middle latitudes of both hemispheres (AMS)
Dominant winds of the mid-latitudes. These winds move from the subtropical highs to the subpolar lows from west to east (PhysGeo.net)

A convex-upward fold is an antiform. Anticlines have older strata in the core. (ethz)
an upward fold where the beds are known not to be overturned (opentext physgeo)
Upwardly arched folds of Sedimentary rocks put under pressure by movement in the Earth

Zone in the Earth's mantle that exhibits plastic properties. Located below the lithosphere (PhysGeo.net)

Climate Normals are three-decade averages of climatological variables including temperature and precipitation (NOAA)
Climate Normals and Averages are used to summarize or describe the average climatic conditions of a particular location (Gov’t of Canada)
the arithmetic average of a climate element such as temperature over a prescribed 30-year interval (Wisconsin State Climatology Office)

involves the transfer of heat energy by means of vertical mass motions through a medium (PhysGeo)
transfer of heat in a gas or liquid by upward movement of the hotter, less dense portion. (ItsEducation)

Heat generated by the breakdown of radioactive minerals in the mantle is redistributed by currents that rise at the mid ocean ridges and descend at the ocean trenches. Convection currents were long thought to be responsible for driving plate motion but this is still the subject of intense debate. (Geo Society)
occur within the molten rock in the mantle, act like a conveyor belt for the plates. Tectonic plates move in different directions. The direction of movement and type of plate margin is determined by which way the convection currents are flowing. (ALevelGeo)

where rock, soil, water, air and living organisms interact and shape the Earth’s surface

The density of air or atmospheric density, denoted p, is the mass per unit volume of Earth's atmosphere (Wiki)
Density is defined as the ratio between mass and volume or mass per unit volume (Study.com)

The erosion or wearing down of a landmass. (2) Removal of the vegetative cover from an area (PhysGeo)
involves the processes that cause the wearing away of the Earth's surface by moving water, by ice, by wind and by waves, leading to a reduction in elevation and in relief of landforms and of landscapes (Wiki)
is an erosive process of breaking and removing the rocks from the surface of the earth (Chegg)

the temperature at which water vapor saturates from an air mass into liquid or solid usually forming rain, snow, frost or dew (PhysGeo)
temperature at which air becomes saturated i.e. relative humidity is 100% (ItsEdu)

the rate of fall in air temperature by adiabatic change as unsaturated air gains altitude. Approximately 1 degree C per 100m. (ItsEdu)
process lapse rate of temperature, the rate of decrease of temperature with height of a parcel of dry air lifted by a reversible adiabatic process through an atmosphere in hydrostatic equilibrium (AMS)

produced or synthesized within system (Webster)
forces having an internal cause or origin (Google)
Processes that are caused by forces from within the Earth (Kiddle)

The rate of decrease of temperature with elevation, -∂T/∂z, or occasionally ∂T/∂p, where p is pressure (AMS)
change in temperature with altitude above a particular point at a particular time. Average is 6.5 degrees C per 1000m. (ItsEdu)
The rate of air temperature increase or decrease with altitude. The average ELR in the troposphere is an air temperature decrease of 6.5° Celsius per 1000 meters rise in elevation (PhysGeo)

(extra-terrestrial) forces are as a result of other bodies in space(Kiddle)
come from forces on or above the Earth's surface (Wiki)
external processes ultimately driven by the sun's energy (CState University)

Igneous rocks that are erupted from a volcano and crystallize at Earth's surface (geology.com)
igneous rock that cooled at surface (opentext physgeo)

A fracture in the rock along which movement takes place. A weak area in the Earth's crust where two sides of a fracture or fracture zone move relative to each other. (bgs)
A fracture or fracture zone in rock along which movement has occurred. When movement occurs the vibrations that are produced are known as an earthquake (geology.com)

Substance that flows and is not solid; smooth and continuous (Merriam)

fold is used in geology when one or a stack of originally flat, level surfaces, such as sedimentary strata, are bent or curved as a result of pressure and high temperature (Wiki)
A wave-like geologic structure that forms when rocks deform by bending instead of breaking under compressional stress. (Geologypage)

Resistance between the contact surfaces of two bodies in motion (Physgeo.net)

Force acting on wind near the Earth's surface due to frictional roughness. Causes the deceleration of wind (PhysGeo.net)
Friction slows the wind down at the surface or in areas with winds of different speeds (wind shear). When the wind is blowing near the surface, the ground creates friction that makes the wind blow slower (NCSU climate)

the boundary where two air masses meet. (ItsEdu)
the interface or transition zone between two air masses of different density (AMS)
Transition zone between air masses with different weather characteristics (PhysGeo)

A geographic coordinate system is a three-dimensional reference system that locates points on the Earth's surface. The unit of measure is usually decimal degrees. A point has two coordinate values: latitude and longitude. Latitude and longitude measure angles.

The field that investigates the origin of landforms on the Earth and other planets (PhysGeo)
is the study of the nature and history of landforms and the processes which create them (DartmouthU)
is the study of landforms and landscapes and the processes that act to modify the Earth’s surface (SFU 213)

Horizontal wind in the upper atmosphere that moves parallel to isobars (PhysGeo.net)
wind blowing parallel to isobars because of deflection of the pressure-gradient force by the Coriolis Force

A direct thermally driven and zonally symmetric circulation under the strong influence of the earth's rotation (AMS)
portion of the tricellular model of air circulation where air rises at the equator due to convection, spreads in the upper troposphere and then sinks over the tropics before returning to the equator. (ItsEdu)

Heat is defined as energy in the process of being transferred from one object to another because of the temperature difference between them. In the atmosphere, heat is commonly transferred by conduction, convection, advection, and radiation (PhysGeography.net)

are places within the mantle where rocks melt to generate magma (oregonstate online)
A hot spot is an area on Earth that exists over a mantle plume. A mantle plume is an area under the rocky outer layer of Earth, called the crust, where magma is hotter than surrounding magma (NatGeo)

Generally, some measure of the water vapor content of air (AMS)
A general term used to describe the amount of water vapor found in the atmosphere (PhysGeo.net)

a rock formed through the cooling of magma or lava (itseducation)
A rock that originated when a molten magma or lava cooled and solidified (bgs)
A rock formed by the crystallization or solidification of molten rock material (geology.com)

Igneous rocks that crystallize below Earth's surface. They typically have mineral crystals that are large enough to easily see with the unaided eye (geology.com)
an igneous rock that has cooled slowly beneath the surface (opentextbc physgeo)

Zone of low atmospheric pressure and ascending air located at or near the equator. Rising air currents are due to global wind convergence and convection from thermal heating (PhysGeo.net)
The axis, or a portion thereof, of the broad trade-wind current of the Tropics (AMS)

the rates at which air temperature decreases with altitude (Itseducationglossary)

Large scale maps show a smaller amount of area with a greater amount of detail. The geographic extent shown on a large scale map is small. A large scaled map expressed as a representative scale would have a smaller number to the right of the ratio. For example, a large scale map could have a RF scale of 1 : 1,000. Large scale maps are typically used to show neighborhoods, a localize area, small towns, etc. (GISLounge)

The angular distance, usually measured in degrees north or south of the equator. Lines of latitude are also referred to as parallels. (ESRI)
Geographic coordinate that specifies the north–south position of a point on the Earth's surface. Latitude is an angle (defined below) which ranges from 0° at the Equator to 90° (North or South) at the poles. (Wiki)

At any moment there is one spot on the Earth where the sun is directly overhead. This spot, called the subsolar point, moves around the Earth in one solar day, 24 hours, thus the subsolar point moves 15 degrees of longitude for each hour of the day. Where this subsolar point is located defines our seasons. (NY University online)

molten rock flowing on the surface (itseducation)
Molten magma that extrudes onto the Earth's surface as a result of a volcanic eruption (bgs)
Molten rock that has erupted onto Earth's surface (geology.com)

The level at which a parcel of moist air lifted dry-adiabatically would become saturated (AMS)

Is the solid inorganic portion of the Earth (composed of rocks, minerals, and elements) (PhysGeo.net)
the crust and upper mantle. Either solid or highly viscous, this layer is not easily deformed or manipulated (itseducation)

is the distance on the earth’s surface, east or west of a defined meridian, usually the meridian of Greenwich, England (0° Longitude), expressed in angular measurements from 180° West (or -180°) to 180° East. (Caliper)
The angular distance, usually expressed in degrees, minutes, and seconds, of the location of a point on the earth's surface east or west of an arbitrarily defined meridian (usually the Greenwich prime meridian). All lines of longitude are great circles that intersect the equator and pass through the North and South Poles. (ESRI)

one of the tools used by exploration geophysicists in their search for mineral-bearing ore bodies or even oil-bearing sedimentary structures and by archaeologists to locate and map the remains of buried structures (Britannica)
are a geophysical method to image anomalies in the earth’s magnetic field caused by source bodies within the sub-surface (SEGwiki)

naturally occurring inorganic solids with a definite chemical composition, and an ordered internal structure (Geology.com) **ordered  regular repeating structure
A naturally occurring inorganic solid with a crystalline structure and a specific chemical composition (PhysGeo.net)

The lower boundary of the crust. At this boundary seismic wave velocities show an increase in speed as they enter the upper mantle (PhysGeo.net)
is the boundary between the crust and the mantle (Geology.com)

The rate of decline in the temperature of a rising parcel of air after it has reached saturation. This rate is less than the dry adiabatic lapse rate (9.8° Celsius per 1000 meters) because of the heat energy added to the ascending air parcel from condensation and deposition processes (PhysGeo)
The rate of decrease of temperature with height along a moist adiabat (AMS)

object that's reduced to liquid form by heating
rock that has been transformed into liquid form by being heated

only one tilted, step-like limb in an otherwise subhorizontal or gently dipping sequence (ethz)
a step-like fold in rock strata consisting of a zone of steeper dip within an otherwise horizontal or gently-dipping sequence (wiki)

A name for seasonal winds (AMS)
A regional scale wind system that predictably change direction with the passing of the seasons (PhysGeo.net)
a seasonal prevailing wind (ItsEdu)

half a sphere. In geography, the division of the earth either into north and south by the equator, or into east and west by any one line of longitude (ItsEducation)

the sideways and upwards movement of the edge of a crustal plate over the margin of an adjacent plate. (google)
The process whereby ocean crust (and even upper mantle) are scraped off the descending ocean plate at a convergent plate boundary and thrust onto the adjoining plate. Often associated with an accretionary wedge (prism). (Geological Society)

studies the spatial patterns of weather and climate, soils, vegetation, animals, water in all its forms, and landforms while also examining the interrelationships of these phenomena with human activities.

ability of certain solids to flow or to change shape permanently when subjected to stresses of intermediate magnitude between those producing temporary deformation (Britannica)

A weak meridional circulation in the high-latitude troposphere characterized by ascending motion in the subpolar latitudes (50°–70°), descending motion over the pole, poleward motion aloft, and equatorward motion near the surface (AMS)
Three-dimensional atmospheric circulation cell located at roughly 60 to 90° North and South of the equator (PhysGeo)

Is any aqueous deposit, in liquid or solid form, that develops in a saturated atmosphere (relative humidity equals 100%) and falls to the ground generally from clouds (PhysGeo)
- movement of water from the atmosphere to the earth’s surface (ItsEdu)
All liquid or solid phase aqueous particles that originate in the atmosphere and fall to the earth's surface (AMS)

It is the force exerted on a surface by the air above it as gravity pulls it to Earth (NatGeo)
The definition of air pressure is the force exerted onto a surface by the weight of the air (YourDictionary)
Is defined as the force acting on a surface from another mass per unit area (PhysGeography.net)

rate of change of pressure over a certain distance (usually is denoted in mb/km) (IowaState University)
The change in pressure measured across a given distance (UIUC online ed)

The ratio of the vapor pressure to the saturation vapor pressure with respect to water (AMS)

stiff and unflexible; not pliant or flexible; firmly set. (Vocabulary.com)

most common mineral component of rock (itseducation)
a hard, unreactive, colorless compound which occurs as the mineral quartz and as a principal constituent of sandstone and other rocks (google definitions)
is the name given to a group of minerals composed of silicon and oxygen, the two most abundant elements in the earth's crust (EUROSIL)

As oceanic lithosphere cools, it becomes denser and thicker. At a convergent plate boundary the oceanic lithosphere sinks beneath the adjacent plate forming an ocean trench and subduction zone. As a result of its own weight, the descending plate is pulled by gravity through the mantle asthenosphere, which is hotter and less rigid. This force is known as slab pull. It is believed to be the major force driving plate motions. (Geo Society)
older, colder plates sink at subduction zones, because as they cool, they become more dense than the underlying mantle. The cooler sinking plate pulls the rest of the warmer plate along behind it. (bgs.uk)

Small scale maps show a larger geographic area with few details on them. The RF scale of a small scale map would have a much larger number to the right of the colon such as 1 : 1,000,000. Small scale maps are used to show the extent of an entire country, region, or continent. (GISLounge)

half a sphere. In geography, the division of the earth either into north and south by the equator, or into east and west by any one line of longitude (ItsEducation)

Subduction occurs when an oceanic plate runs into a continental plate and slides beneath it. (usgs.gov)
the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate. (google)

Theory suggesting that the Earth's surface is composed of a number of oceanic and continental plates. Driven by convection currents in the mantle, these plates have the ability to slowly move across the Earth's plastic asthenosphere. (PhysGeo.net)

is a measure of the intensity or degree of hotness in a body. Technically, it is determined by getting the average speed of a body's molecules (PhysGeography.net)
Temperature is the degree of hotness or coldness of the atmosphere on some chosen scale. It is commonly measured in Celsius or Fahrenheit (Wikibooks)

The line that circumscribes the earth and connects all points of highest mean annual temperature for their longitudes (AMS)
Continuous area on the globe that has the highest surface temperatures because of the presence of the Intertropical Convergence Zone (PhysGeo.net)

Surface winds that generally dominate air flow in the tropics. These winds blow from about 30° North and South latitude to the equator (PhysGeo.net)
The wind system, occupying most of the Tropics, that blows from the subtropical highs toward the equatorial trough; a major component of the general circulation of the atmosphere (AMS)

one in which two plates slide past one another and crust is neither created nor destroyed, but is conserved (Geo Society)
are places where plates slide sideways past each other. At transform boundaries lithosphere is neither created nor destroyed (Cornell Online)

Latitude of 23.5° North. Northern limit of the Sun's declination
Latitude of 23.5° South. Southern limit of the Sun's declination (PhysGeo.net)

Pressure exerted by water vapor molecules in a given quantity of atmosphere (PhysGeo.net)
The pressure exerted by the molecules of a given vapour (AMS)

the gaseous phase of water (Wiki)
water in its gaseous state-instead of liquid or solid (ice) (weatherstreet)

Physical, chemical or biological breakdown of rocks and minerals into smaller sized particles.
breakdown of rock in situ by physical and chemical processes due to the presence of water, plants and animals (Itseducation)
is the breakdown of rocks at the Earth’s surface, by the action of rainwater, extremes of temperature, and biological activity (Geological Society)