Aurora, Atmospheric Phenomena, and Meteorology: Key Concepts
Aurora
An aurora is a glow that appears in the night sky, usually in polar regions. In the Northern Hemisphere, it is known as the Aurora Borealis, and in the Southern Hemisphere, it is known as the Aurora Australis.
Origin of the Aurora Borealis or Polaris
An aurora originates when a solar mass ejection collides with the north and south poles of the Earth’s magnetosphere, which is projected to the ionosphere.
Variation of Temperatures
- Diurnal Variation: The change in temperature between day and night produced by the rotation of the Earth.
- Stationary Variation with Latitude: With the types of surface, it should be due to their different capacity for absorption and emission of radiation.
- With Height: Temperature typically decreases with altitude.
Temperature Inversions
This occurs in the boundary layer of the atmosphere. The absolute temperature in the boundary layer usually decreases with height, but under certain conditions, the absolute temperature increases significantly with height from a certain latitude. This point is called the inversion height.
Inversion
An increase in temperature with latitude.
Types of Inversions
- High-Altitude Inversion: When a warm air mass moves over a land area that is colder and is likewise forced to rise.
- Surface Inversion: When a mass of cold air moves under a hot mass.
Atmospheric Pressure
Atmospheric pressure is the pressure exerted by air at any point in the atmosphere. Maximum atmospheric pressure occurs at sea level and decreases with increasing latitude.
Types of Meteorological Satellites
- Polar Synchronous
- Geostationary
Cyclones
Cyclones are air masses that ascend.
Types of Cyclones
- Thermal Cyclone: The air mass rises because it is hotter than its environment. It is typical of tropical regions and involves a period of cloudiness, rain, and warmth.
- Dynamic Cyclone: The air mass is forced upward by the movement of polar air.
Anticyclones
Anticyclones are air masses that descend.
Types of Anticyclones
- Thermal Anticyclone: The air mass descends because it is colder than its environment.
- Dynamic Anticyclone: The air mass descends because it is pushed downward by the collision of cold air from the polar front and tropical air at height.
Coriolis Effect
The Coriolis effect is the force produced by the rotation of the Earth in space, which tends to deflect the trajectory of moving objects on the Earth’s surface to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Local Winds
Local winds are given by breezes:
- Land and Sea Breezes
- Mountain and Valley Breezes
Foehn Effect
This name is given to the heating of the air when it is forced to descend on the leeward side of a mountain.
Regional Winds
Regional winds are given by:
- Monsoon Circulation: The difference is due to the warming experienced by oceans and continents. Oceanic waters have a higher specific heat than continents, so they take longer to warm up.
- Tropical Cyclone: This is a weather term used to refer to a storm system characterized by a closed circulation around a low-pressure center that produces strong winds and heavy rain. Depending on its strength and location, it may be termed a tropical depression, tropical storm, hurricane, or simply cyclone.
Air Mass
An air mass possesses similar properties over a large area.
Front
A front is a transition area between two air masses with different physical properties.
Hydrometer
A hydrometer measures the specific gravity of liquids.
Precipitation Classes
- Cyclonic: Can be frontal (cold front and warm front) or non-frontal, and the latter occurs in any low depression.
- Convective: Originates in the instability of a warm air mass surrounding another. It is in the form of showers.
- Orographic: This is the precipitation that has its origin in the rise of an air mass forced by a mountain barrier. It takes the form of rain or snow regularly.
Precipitation Types by Drop Form
- Rain: > or = 1/2 mm
- Drizzle: < 1/2 mm
- Shower: Liquid or solid
- Sleet