308M Temperature, Moisture and Heat Transfer

What is heat defined as in meteorology?

Energy that is being transferred from one object to another due to a temperature difference between them.

How does the Earth's surface primarily heat the atmosphere?

The Earth absorbs short-wave solar radiation and reradiates it as long-wave (terrestrial) radiation, which the atmosphere absorbs.

What is albedo?

The measure of how reflective a substance is.

A substance with a high albedo will _ a high percentage of solar radiation.

reflect

Which surface has a higher albedo: water or ice/snow?

Ice and snow have a higher albedo, reflecting more energy.

What is temperature a measure of?

The warmth or coldness of an object or substance with reference to a standard value.

In Canada, what is the standard unit for measuring temperature in meteorology?

Celsius (°C).

What is latent heat?

The energy required to change a substance from one state to another at a constant temperature.

When water evaporates, is latent heat absorbed from or released into the environment?

Latent heat is absorbed from the environment and stored in the water vapor.

When water vapor condenses into liquid, what happens to the latent heat?

The stored latent heat is released back into the air as latent heat of condensation.

What term describes the condition when a parcel of air holds the maximum amount of moisture it can at its current state?

Saturated.

What is absolute humidity?

The measure of water vapor (moisture) in the air, regardless of temperature, expressed as grams per cubic meter (g/m³).

What is relative humidity?

The amount of water vapor in the air expressed as a percentage of the total amount that could be held at its current temperature.

If an air parcel has a relative humidity of 100%, it is considered to be _.

saturated

What is the dew point?

The temperature to which air must be cooled for saturation to occur.

The difference between the air temperature and the dew point is commonly referred to as the _.

spread

What does a small temperature-dew point spread indicate about the air's humidity?

It indicates high humidity and that the air is close to saturation.

If the temperature and dew point are identical, what is the state of the air?

The air is saturated, and condensation is likely to occur.

What happens to relative humidity if the air temperature increases but the amount of moisture remains constant?

The relative humidity decreases.

What happens to relative humidity if the air temperature decreases but the amount of moisture remains constant?

The relative humidity increases.

The process where moisture changes from a liquid to a gas is called _.

evaporation

The process where water vapor changes into liquid water is called _.

condensation

What is the term for the transition of a substance directly from a solid to a gas, or vice versa, without passing through the liquid phase?

Sublimation.

The formation of frost on aircraft wings from water vapor is an example of what process?

Sublimation (specifically, deposition).

Which can hold more water vapor: warm air or cold air?

Warm air can hold more water vapor than cold air.

What are the three conditions required for condensation to occur?

The presence of condensation nuclei, saturated air (100% RH), and cooling of the air.

What are condensation nuclei?

Microscopic solid particles suspended in the atmosphere that provide a surface for water vapor to condense upon.

If an air parcel is cooled without adding or removing moisture, what happens to its dew point and relative humidity?

The dew point remains constant, and the relative humidity rises until saturation is reached.

Once cooling air reaches saturation, what happens to the dew point and relative humidity if the temperature continues to drop?

The dew point falls along with the temperature, and the relative humidity remains at 100% as condensation occurs.

If an air parcel is heated without adding or removing moisture, what happens to its dew point and relative humidity?

The dew point remains constant, and the relative humidity drops.

What are the four processes of heat transfer in the atmosphere?

Radiation, conduction, convection, and advection.

What is radiation in the context of heat transfer?

The transfer of heat energy in the form of electromagnetic waves.

What is conduction?

The transfer of heat energy by direct contact between two bodies at different temperatures.

Why is conduction primarily effective only in the lowest meter of the atmosphere?

Because air is a poor conductor of heat (an insulator).

What is convection in meteorology?

The vertical transfer of heat through the circular motion of a fluid (like air), where warmer, less dense air rises and cooler air sinks.

What is advection?

The horizontal transfer of heat or other properties by the bulk motion of a fluid, such as wind.

According to the principle of heat transfer, in which direction does heat flow?

Heat is transferred from a warmer body to a cooler body.

The process where the Earth cools at night by radiating its heat away is known as _ cooling.

radiation

What is advection cooling?

The cooling of an air mass that occurs when warm air moves horizontally over a colder surface.

What is advection heating?

The warming of an air mass that occurs when cool air moves horizontally over a warmer surface.

What are the four processes by which the atmosphere is heated?

Radiation (from the Earth's surface), conduction, convection, and advection heating.

What are the two primary processes by which the atmosphere is cooled?

Radiation cooling (at night) and advection cooling.

The heat energy stored in water vapor during evaporation is known as the latent heat of _.

condensation

A METAR observation showing the temperature and dew point as '10/10' indicates what condition?

The air is saturated, with a relative humidity of 100%.

Relative humidity is not a true indicator of the air's moisture content, but rather an indicator of its degree of _.

saturation

What atmospheric phenomenon is likely when warm, moist air moves over a cold surface?

Advection fog, due to advection cooling.

The vertical currents that birds use to soar, often found over paved surfaces on sunny days, are called _.

thermals (a form of convection)