Airmasses and humidity

Question 1

what is the definition of an air mass

Answer 1

A widespread body of air, with properties such as…
Having been established while that air was situated over a particular region n the earths surface (airmass source region)

Question 2

What are air masses that originate from tropical oceans called

Answer 2

Stagnant

Question 3

What are air masses that originate from major continents called

Answer 3

Conditions

Question 4

What is some more basic information about air masses

Answer 4

Form in homogenous areas and undergo modification as they move away, meeting and interacting in areas such as the British isles

Question 5

what are the air masses that affect the British isles called

Answer 5

Polar Maritime, returning polar maritime, tropical maritime, tropical continental, polar continental and arctic maritime

Question 6

What is lapse rate

Answer 6

The lapse rate is the rate at which an atmospheric variable usually temperature in earths atmosphere falls with altitude

Question 7

what is the dry adiabatic lapse rate (DALR)

Answer 7

9.8 degrees Celsius every 1km you move up through the atmosphere

Question 8

what is the moist adiabatic lapse rate (MALR)

Answer 8

Varies with temperature, but as a general average, its about 5 degrees every 1km that you move up through the lower part of the atmosphere

Question 9

what does cold air over a relatively warm sea mean

Answer 9

Convective instability

Question 10

what is convective instability

Answer 10

The ability of an air mass to resist vertical motion. A stable atmosphere makes vertical movement difficult, and small vertical disturbances dampen out and disappear

Question 11

what is a place where ocean currents and air masses meet

Answer 11

New Foundland Canada

Question 12

What is key in identifying air masses

Answer 12

Humidity

Question 13

What is the dry bulb temperature

Answer 13

The temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. The dry bulb is usually thought of as the air temperature, and it is the true thermodynamic temperature

Question 14

Why is dry bulb temperature not a great indicator for air masses

Answer 14

Does not account for moisture in the air, It is affected by radiation (heats up by day, cools down by night). Affected by vertical motion (lapse rates), i.e. it normally gets cooler as you walk up a mountain. It is affected by addition or subtraction of moisture from air, i.e evaporative cooling (why you feel cold when you get out a shower or bath

Question 15

What is isobaric wet bulb temperature

Answer 15

The temperature an air parcel would have if cooled to saturation at constant pressure by evaporation of water into it, all latent heat being supplied by the parcel

Question 16

What is specific humidity (Q)

Answer 16

The density of water vapor (mass per unit volume) divided by the density of all air, including the water vapour

Question 17

What is the mixing ratio (R)

Answer 17

The ratio of the mass of water vapour to the mass of dry air. For many purposes, the mixing ratio may be approximated by the specific humidity

Question 18

Explain vapour pressure (e)

Answer 18

As the water molecules escape to the atmosphere by evaporation, they take energy from the water. The water cools and the atmosphere gains water vapour. Some of the water vapour molecules will return to the water, setting up a two way flux between the water and air above it

Question 19

What is the basic definition of vapour pressure

Answer 19

The vapour pressure (e) is the part of the total pressure above the water surface due to the water vapour molecules

Question 20

Saturation Vapour pressure (es)

Answer 20

At saturation, the atmosphere above the water surface holds the maximum amount of vapour it can at that temperature and pressure. The Vapour at this pressure is the saturation pressure. Measured in pascals