Atmospheric Structure and General Concepts

Atmosphere

The layer of gases surrounding Earth, held by gravity. The atmosphere is composed mainly of nitrogen and oxygen and plays a crucial role in weather and climate by containing air, moisture, and heat.

Meteorology

The scientific study of the atmosphere and weather processes. Meteorologists analyze data to forecast weather and understand climate behavior.

Atmospheric Pressure

The force exerted by the weight of air in the atmosphere. It influences weather patterns and is measured in units like millibars or inches of mercury.

Pressure Gradient

The rate of atmospheric pressure change over a certain distance, influencing wind speed and direction. A steep pressure gradient results in stronger winds.

Potential Temperature

The temperature air would have if compressed or expanded adiabatically to a standard pressure level, used to assess atmospheric stability.

Advection

The horizontal transport of heat, moisture, or other atmospheric properties by the wind. This process redistributes energy and moisture across different regions.

Lapse Rate

The rate at which air temperature decreases with increasing altitude. Understanding lapse rates is important for weather prediction and aviation.

Inversion

A reversal of the normal decrease of air temperature with altitude, trapping pollutants near the ground. Temperature inversions can lead to smog and poor air quality.

Freezing Rain

Rain that falls as liquid but freezes upon contact with cold surfaces, causing ice accumulation.

Adiabatic Process

A process in which air changes temperature without exchanging heat with its surroundings, typically as it rises or sinks in the atmosphere.

Barotropic Atmosphere

An atmospheric condition where temperature depends only on pressure, resulting in no horizontal temperature gradients.

Dew Point Temperature

The temperature at which air becomes saturated and water vapor begins to condense into liquid dew.

Geopotential Height

The height of a pressure surface in the atmosphere measured relative to Earth’s mean sea level, used to analyze atmospheric pressure and temperature patterns.

Isallobar

A line on a weather map connecting points of equal change in atmospheric pressure over a specified time, useful for predicting wind trends.

Kelvin Wave (Atmospheric)

A large-scale wave in the atmosphere that propagates along the equator, influencing tropical weather and climate patterns.

Lifted Condensation Level (LCL)

The altitude at which an air parcel becomes saturated when lifted adiabatically, marking cloud base height.

Parcel Theory

A concept in meteorology where an air parcel is considered isolated for thermodynamic calculations, useful in predicting stability.

PBL (Planetary Boundary Layer)

The lowest part of the atmosphere directly influenced by the Earth's surface, where most weather phenomena occur.

Potential Vorticity

A conserved quantity combining vorticity and stratification, useful for understanding large-scale atmospheric motions and weather systems.

Pressure Tendency

The change in atmospheric pressure over a specific time period, helping forecast short-term weather changes.

Quasi-Geostrophic Theory

A simplification of atmospheric dynamics used to describe large-scale flow and predict weather patterns.

Relative Humidity

The percentage of moisture in the air relative to the maximum it can hold at that temperature. It affects comfort, evaporation, and cloud formation.

Relative Vorticity

The rotation of air parcels relative to the Earth’s surface, influencing the development of cyclones and anticyclones.

Sensible Heat

Heat exchanged between the Earth's surface and the atmosphere that results in a temperature change, without phase change of water.

Temperature Gradient

The rate of temperature change over a distance, crucial for identifying fronts and weather patterns.

Tropopause

The boundary layer between the troposphere and the stratosphere where temperature stops decreasing with height, acting as a cap for most weather phenomena.

Tropopause Fold

A phenomenon where stratospheric air intrudes into the troposphere, often linked to dynamic weather events.