Atmospheric Conditions and Weather Patterns

Comprehensive vocabulary flashcards covering atmospheric conditions, heat transfer, pressure belts, wind types, humidity, and rainfall types based on the lecture notes.

Weather

Atmospheric conditions such as temperature, pressure, wind, humidity and precipitation experienced for a shorter period of time in a region.

Climate

The average weather condition experienced for a longer period over a larger area.

Insolation

The amount of sun's rays reaching the earth's surface in the form of short waves.

Conduction

A process where heat is transferred to the lower part of the atmosphere which is directly in contact with the surface of the earth.

Convection

A process where heat is transferred to higher reaches of the atmosphere as heated air expands and rises up.

Advection

The horizontal transfer of heat through wind.

Radiation

The emission of energy in the form of long waves after the earth's surface gets heated up.

Green House Effect

The phenomenon where atmospheric gases such as carbon dioxide absorb terrestrial radiation and heat up the atmosphere.

Heat Budget of the Earth

The process of heat balancing where almost entire energy reaching the earth as insolation is radiated back, keeping the surface temperature balanced.

Maximum Daily Temperature

The highest temperature of the day, typically experienced at $2\,PM$.

Minimum Daily Temperature

The lowest temperature of the day, typically experienced just before the sun rise.

Diurnal range of temperature

The difference between the maximum temperature and the minimum temperature of a day, calculated as $\text{Maximum temperature} - \text{Minimum temperature}$.

Daily mean temperature

The average temperature of a day, calculated as $\frac{\text{Maximum temperature} + \text{Minimum temperature}}{2}$.

Isotherms

Imaginary lines drawn connecting places having equal temperature.

Atmospheric Pressure

The weight exerted by the atmospheric air over the earth's surface.

Barometer

The instrument used to measure atmospheric pressure.

Pressure-Altitude Relationship

Atmospheric pressure decreases with altitude at a rate of $1\,mb$ per an altitude of $10\,m$.

Isobar

Imaginary lines connecting places having equal atmospheric pressure.

Equatorial Low Pressure Belt

A pressure belt formed by the expansion and rising of air due to high temperature in the equatorial region; also known as Doldrum.

Sub Tropical High Pressure Belts

Pressure belts situated at $30^{\circ}$ North and South latitudes where cooled upper air winds from the equator subside.

Sub Polar Low Pressure Belts

Belts situated at $60^{\circ}$ North and South latitudes where colder air is thrown up due to the rotation of the earth.

Polar High Pressure Belts

Belts formed as a result of the contraction and subsidence of cold air along the poles.

Air Currents

The vertical movements of air.

Winds

The horizontal movements of air from high pressure areas to low pressure areas.

Anemometer

An instrument used to measure the speed of wind.

Wind Vane

An instrument which indicates the direction of wind.

Coriolis Force

A factor influencing wind direction that causes deflection towards the right in the Northern Hemisphere and towards the left in the Southern Hemisphere.

Permanent Winds

Winds blowing constantly over a particular direction throughout the year; also known as prevailing or planetary winds.

Trade winds

Permanent winds blowing from the Sub tropical high pressure belts to the equatorial low pressure belt.

Westerlies

Permanent winds blowing from the Sub tropical high pressure belts to the Sub polar low pressure belt; stronger in the Southern Hemisphere due to vast oceans.

Periodic Winds

Winds subjected to the periodic reversal of their direction, such as breezes and monsoon winds.

Mountain Breezes

Periodic winds that move down slope along the mountain during the night.

Valley breezes

Periodic winds where air above mountain slopes is heated by sunlight and blows up slope from the valley during the day.

Monsoon Winds

The seasonal reversal of a wind system.

Local Winds

Winds formed as a result of local differences in temperature and pressure.

Variable Winds

Winds of short duration with unpredictable intensity or direction, such as Cyclones and Anticyclones.

Cyclones

Low pressure systems where winds whirl inward; rotating anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Anticyclones

High pressure systems from which winds whirl outwards; rotating clockwise in the Northern Hemisphere and anticlockwise in the Southern Hemisphere.

Humidity

The invisible water content in the atmosphere.

Hygrometer

An instrument used to measure atmospheric humidity.

Absolute humidity

The actual amount of water vapour present per unit volume of atmosphere.

Relative Humidity

The ratio between the actual amount of water present in the atmosphere and the total water-holding capacity at a specific temperature.

Saturation level

The state at which the atmosphere is fully saturated with water vapour.

Saturation Point

The temperature at which a fully saturated level is attained.

Condensation

The process by which water vapour in the air is changed into liquid water.

Cirrus clouds

Thin, delicate, feather-like clouds.

Stratus clouds

Thick-layered clouds.

Cumulus Cloud

Cotton wool-like clouds.

Nimbus Cloud

Dark, rain-bearing clouds.

Precipitation

The release of water droplets from clouds in various forms, occurring when the droplets grow beyond the limit of resistance against gravity.

Orographic rainfall

Rainfall caused when moisture-laden winds from the sea are raised along mountain slopes, also called Relief rainfall.

Convectional Rainfall

Rainfall occurring in the afternoon during summer through the convection process.

Cyclonic Rainfall

Rainfall resulting from warm air being raised up during cyclonic activity to cause condensation.

Rain Shadow Region

The leeward side of a mountain which remains rainless while the windward slope receives more rainfall.

Frontal Rainfall

Rainfall that occurs at the boundary lines, known as fronts, where warm and cold air meet.