Thermal Processes

Question 1

what is an adiabatic process

Answer 1

An adiabatic process is one in which no energy enters or leaves the system

Question 2

give two examples of adiabatic processes

Answer 2

Ascent of dry convective plumes

Large scale lifting/subsidence

Question 3

give some examples of non adiabatic processes

Answer 3

Radiative heating/cooling
Surface heating/cooling
Loss of water through precipitation
Addition of water from evaporation of precipitation falling from above
Condensation/evaporation within an airmass is known as “pseudoadiabatic”

Question 4

what is lapse rate

Answer 4

Lapse Rate is the term given to the vertical gradient of temperature.
The fall in temperature with altitude of dry air that results from the decrease in pressure is called the Dry Adiabatic Lapse Rate = -9.8°C/km.

Question 5

does saturated air cool more or less with altitude

Answer 5

less

Question 6

what is potential temperature

Answer 6

• moving a mass of air adiabatically in the vertical will result in a change in temperature as the pressure changes
• can account for this using potential temperature. this is the temperature the mass of air would have if moved adiabatically to a reference pressure (1000hPa)
• potential temperature is conserved as a mass of air is moved adiabatically, the temp is not

Question 7

what happens to air if it is warmed

Answer 7

the air will expand and its density will decrease

Question 8

what is a thermal low a result of

Answer 8

the strong contrast in surface heating between land and sea

Question 9

what is a thermal low

Answer 9

Land heats up (solar radiation) and cools down (infra-red radiation) much more rapidly than ocean large diurnal cycle cross-coast temperature gradient

Question 10

does a thermal low result from a depression?

Answer 10

no it results from fine clear warm weather

Question 11

what is a sea breeze

Answer 11

In-flowing cool air from the sea forms a sea-breeze front – a miniature cold front