Weather and Climate – Key Vocabulary

A set of vocabulary flashcards summarizing essential terms from the Weather and Climate lecture, covering temperature controls, humidity, precipitation, winds, monsoons, and climate types.

Weather

The state of atmospheric conditions (e.g., temperature, cloud cover, precipitation, wind) at a particular time and place.

Climate

The average state of atmospheric conditions over a specified period, typically 25 years or more.

Climograph

A combined bar-and-line graph that shows a place’s average monthly temperature and precipitation.

Climatic Hazard

A sudden change in climate or an extreme weather event such as heat waves, droughts, floods, cyclones, or wildfires.

Air Temperature

A measure of the degree of hotness or coldness of a place, commonly read with thermometers.

Analogue Thermometer

A liquid-in-glass or dial device used to read current air temperature.

Maximum and Minimum Thermometer

An instrument that records the highest and lowest temperatures reached over a period.

Solar Radiation

Incoming short-wave energy from the Sun that heats Earth’s surface.

Terrestrial Radiation

Outgoing long-wave energy emitted by Earth’s surface that warms the overlying atmosphere.

Earth’s Rotation

The 24-hour spin of Earth on its axis that causes daily temperature variability.

Earth’s Revolution

Earth’s yearly orbit around the Sun that causes seasonal temperature variability.

Latitude

The distance of a point north or south of the equator, affecting solar angle and temperature.

Altitude

The vertical distance of a location above mean sea level; temperature decreases about 6.5 °C per 1000 m.

Heating-from-Below Effect

Warming of the lowest air layers by long-wave radiation emitted from Earth’s heated surface.

Air Density

The mass of air molecules in a given volume; denser at low altitudes and able to absorb more heat.

Greenhouse Gases

Atmospheric gases (e.g., CO₂, H₂O vapor) that trap long-wave radiation and warm the lower atmosphere.

Albedo

The percentage of incoming solar radiation reflected by a surface; high for snow, low for dark soil.

Maritime Effect

Moderation of coastal temperatures by the slow heating and cooling of large water bodies.

Continental Effect

Greater temperature extremes in inland areas due to rapid heating and cooling of land.

Annual Temperature Range

The difference between the warmest and coolest monthly mean temperatures of a place.

Relative Humidity (RH)

The ratio (in %) of the actual water-vapor content to the maximum possible at a given temperature.

Dew Point Temperature

The temperature at which air becomes saturated (RH = 100 %) and condensation begins.

Saturation

The condition where air’s relative humidity reaches 100 % and cannot hold additional water vapor.

Condensation Nucleus

A tiny airborne particle (dust, salt, smoke) on which water vapor condenses to form cloud droplets.

Water Cycle

The continuous movement of water between atmosphere and Earth through evaporation, condensation, precipitation, runoff, and groundwater flow.

Evapotranspiration

Combined water loss to the atmosphere by evaporation from surfaces and transpiration from plants.

Infiltration

Downward movement of water from the surface into soil and rock.

Surface Runoff

Water flow over land that enters streams after precipitation.

Groundwater Flow

Subsurface movement of water within saturated rock or soil layers toward outlets.

Convectional Rain

Rain produced by localized surface heating, rising unstable air, and cumulonimbus cloud formation.

Relief (Orographic) Rain

Rainfall generated when moist air is forced to rise over a mountain barrier, cooling and condensing on the windward side.

Cumulonimbus Cloud

A towering cloud with vertical development that often produces heavy showers and thunderstorms.

Windward Side

The side of a mountain that faces prevailing winds and receives heavy precipitation.

Leeward Side

The sheltered side of a mountain where descending air creates drier conditions (rain shadow).

Air Pressure

The downward force exerted by the weight of the column of air above a unit area; average sea-level value is 1013 mb.

Pressure Gradient

The difference in air pressure between two locations; determines wind speed.

Wind

Horizontal movement of air from areas of high pressure to areas of low pressure.

Coriolis Effect

Deflection of moving air caused by Earth’s rotation—rightward in the Northern Hemisphere, leftward in the Southern Hemisphere.

Land Breeze

Night-time coastal wind that blows from cooler land (high pressure) to warmer sea (low pressure).

Sea Breeze

Day-time coastal wind that blows from cooler sea (high pressure) to warmer land (low pressure).

Monsoon

A regional wind system that reverses seasonally, producing wet and dry periods.

Northeast Monsoon

Cold, dry wind blowing from Central Asia toward Australia (Oct–Feb), bringing heavy rain to northern Australia after crossing the equator.

Southwest Monsoon

Moist wind blowing from Australia toward Central Asia/India (Jun–Sep), bringing abundant summer rainfall to the Indian sub-continent.

Tropical Equatorial Climate

Climate near 10° N–S with high, uniform temperatures (~27 °C) and >1500 mm evenly distributed rainfall.

Tropical Monsoon Climate

Climate 5°–25° N/S characterized by small temperature range and highly seasonal rainfall with wet summers and dry winters.

Cool Temperate Climate

Climate 40°–60° N/S featuring mild winters (~4 °C), cool summers (~18 °C), large annual temperature range, and moderate precipitation.

Path Length (Solar Radiation)

The distance solar rays travel through the atmosphere; longer at high latitudes, causing greater heat loss.

Angle of Incidence

The angle at which sunlight strikes Earth’s surface; higher angles concentrate energy and raise temperatures.

Small Temperature Range

An annual or diurnal range of less than 10 °C.

Large Temperature Range

An annual or diurnal range greater than 15 °C.

High-Pressure Cell

An area where air is sinking and pressure is above 1013 mb; generally associated with cool or dry conditions.

Low-Pressure Cell

An area where air is rising and pressure is below 1013 mb; often associated with warm or moist conditions.

Humid Air

Air with relative humidity above 80 %, but below saturation.

Dry Air

Air with very low moisture content; relative humidity near 0 %.

Absolute Humidity

The actual mass of water vapor present in a given volume of air (g m⁻³).

Stable Air

A parcel of air that is cooler than its surroundings and resists rising.

Unstable Air

A parcel of air that is warmer than its surroundings, rises freely, and may lead to cloud formation.

Precipitation

Any form of water (rain, snow, sleet, hail) that falls from clouds to Earth’s surface.

Cloud

A visible mass of tiny water droplets or ice crystals suspended in the atmosphere.

Short-Wave Radiation

High-energy solar radiation received by Earth, primarily in the visible and ultraviolet wavelengths.

Long-Wave Radiation

Lower-energy infrared radiation emitted from Earth’s warmed surface back to space.

Axial Tilt

The 23.5° inclination of Earth’s rotational axis, responsible for seasonal variations.

Tropic of Cancer

The latitude 23.5° N where the Sun is directly overhead at the June solstice.

Arctic Circle

Latitude 66.5° N, marking the region of 24-hour daylight or darkness at solstices.

Climate Change

Long-term alteration in average climate conditions that can increase frequency or intensity of climatic hazards.

Scattering (Solar Radiation)

Redirection of solar rays by atmospheric particles, reducing the amount reaching Earth’s surface.

Reflection (Solar Radiation)

The bouncing of solar radiation back to space by clouds, snow, or light-colored surfaces.

Absorption (Solar Radiation)

The uptake of solar energy by atmospheric gases, clouds, or Earth’s surface.

Specific Heat Capacity

The amount of heat required to raise the temperature of a substance; higher for water than land.

Thermal Comfort

A measure of human comfort determined by temperature, humidity, and wind.

Pressure Gradient Force (PGF)

The driving force that moves air horizontally from high toward low pressure areas.

Friction Force

The drag exerted by Earth’s surface that slows and alters low-level wind flow.

Prevailing Wind

The most frequent wind direction observed at a location over a specified period.

Isobar

A line on a weather map connecting points of equal air pressure.

Rain Shadow

A dry area on the leeward side of a mountain where descending air warms and suppresses precipitation.