Temperature and Heating - Meteorology Notes (Flight School)

Flashcards covering key concepts from the notes on temperature, radiation, heating processes, and seasonal/diurnal variations.

What is the key element in the production of weather?

Temperature

Name the three common temperature scales and a key point for each (freezing/boiling):

Celsius: freezing 0°C, boiling 100°C; Fahrenheit: freezing 32°F, boiling 212°F; Kelvin: starts at 0 K, Absolute Zero at -273°C.

Celsius to Fahrenheit conversion formula?

(°C × 1.8) + 32

Fahrenheit to Celsius conversion formula?

(°F − 32) ÷ 1.8

Celsius to Kelvin conversion formula?

°C + 273 (approximate; 273.15 is often used)

In a thermograph reading, how many millimetres does one hour correspond to?

11.5 mm

On a thermograph, how much does one division represent in temperature?

0.5°C

What is shown in the interior meteorological shelter (Page 6) with forced air circulation and thermistors?

A thermometer setup including a psychrometer for humidity measurements and digital data collection

What is a radiosonde and how does it work?

A sensor package attached to a hydrogen balloon that measures temperature at various altitudes and transmits data to a ground station; launches are published in NOTAMs.

Define albedo.

Albedo is the reflectivity value of a surface; high albedo surfaces reflect more energy, low albedo surfaces absorb more energy.

Compare the specific heat capacity of water and land.

Water has high SHC (~4.2), heats/cools slowly; land has low SHC (~0.8), so temperature changes faster.

What percentage of solar radiation reaches the surface on a clear day and what percentage is absorbed by ozone?

Approximately 85% reaches the surface; about 15% is absorbed by ozone in the upper atmosphere.

What is Terrestrial Radiation?

The Earth radiates thermal energy; Earth is colder than the Sun and has longer-wavelength radiation; atmospheric gases absorb these longer waves, heating the atmosphere.

Which radiation primarily heats the atmosphere: solar or terrestrial radiation?

Terrestrial (surface) radiation heats the atmosphere; most heating occurs near the surface.

Why is the atmosphere densest near the surface and how does this relate to heating?

The atmosphere is densest near the surface; as a result, most heating occurs near the surface.

What is the Standard Lapse Rate?

-2°C per 1000 ft (approximately 2°C/1000 ft used in calculations)

What is conduction?

Transfer of heat between substances by direct physical contact; air is a poor conductor; conduction mainly occurs in the lower troposphere.

What is convection?

Vertical transfer of heat; warm air rises and cools, causing turbulent mixing; can involve rapid vertical movement (up to ~10,000 ft per minute)

What is advection?

Horizontal transfer of heat; in temperate latitudes, winter; sea warmer than land; sea breeze; fog can form.

What is latent heat?

Heat released or absorbed during a change of state (liquid to gas) without a temperature change; energy is exchanged with surroundings.

What are the two main types of temperature variations?

Daily variations and seasonal variations.

What factors determine insolation variations?

Insolation depends on reflectivity (albedo) and angle of incidence; more direct sunlight concentrates energy; less direct spreads energy.

Which region receives the most direct sunlight?

The Equator receives more direct sunlight; polar regions receive much less energy.

What is the Earth's axial tilt used in seasonal diagrams?

23.5 degrees

Perihelion and Aphelion dates (approximate)?

Perihelion around January 4; Aphelion around July 4.

What is the typical time of day when the daily maximum temperature occurs (diurnal cycle)?

Around 1500 hours local time due to heating lag.

When is the maximum daily temperature typically reached over land?

Approximately 15:00 (3:00 pm) local time.

How does cloud cover affect surface temperatures during day and night?

Day: more clouds reduce insolation and cool the surface; Night: clouds absorb longwave radiation and trap heat (greenhouse effect).

What is the Environmental Lapse Rate (ELR)?

Rate of temperature change with height; standard ELR ~2°C per 1000 ft; actual ELR varies with conditions.

What is an isothermal layer?

A layer where temperature remains constant with height.

What is an inversion layer?

A nocturnal inversion where temperature increases with height in a layer.

What does a steep ELR indicate?

It can indicate unstable atmospheric conditions and promote convection (forms under certain conditions).

How do high vs low albedo surfaces affect temperature?

High albedo surfaces reflect more energy and tend to stay cooler or constant; low albedo surfaces absorb more energy and temperature rises.

How does insolation relate to the angle of incidence?

Direct (high) angle of incidence concentrates energy; oblique (low) angles spread energy over a larger area.

What does NOTAM stand for in radiosonde launches?

Notice to Airmen; NOTAMs publish the launch of radiosonde balloons.