Topic 5: Regional Scale Flows

Question 1

Put in order of lowest to highest albedo: dry soil, snow, grass, water.

Answer 1

water < grass < dry soil < fresh snow

Question 2

Q* is ___over water and ___over the continent. Overall energy available to warm up the surface and the atmosphere is___ over the ocean than over land

Answer 2

higher over water and lower over continent. available energy is greater over the ocean

Question 3

How is energy used in the radiation budget?

Answer 3

net radiation, Q*, is used to warm up the surface. this promotes evaporation and convection towards the atmosphere. heat is also conducted through the soil

Question 4

What affects heat capacity?

Answer 4

molecular property of each material determines how the energy is distributed and how long it takes for the material to warm up.

Question 5

Compare and contrast sea and land properties.

Answer 5

Sea: albedo = 0.05, larger daytime radiation, 0.1 bowen ratio, Qe dominates

Land: albedo = 0.2, smaller Q* (smaller albedo), >1 bowen ratio, Qh dominates

Question 6

Over the ocean: Q* is large, heat capacity is ___, diurnal cycle is ____, bowen ratio is ____, sensible heat flux is ____, latent heat flux is____

Answer 6

Over the ocean: heat capacity is large, diurnal cycle is small, bowen ratio is very small, sensible heat flux is almost zero, latent heat flux is the dominant convective flux

Question 7

Over the land: Q* is ____, heat capacity is ___, diurnal cycle is ___, bowen ratio is ___, sensible heat flux is ___

Answer 7

Over the ocean: Q* is smaller, heat capacity is small, diurnal cycle is larger, bowen ratio is large, sensible heat flux is dominant

Question 8

The Marine boundary layer is
1.
2.
3.

Answer 8

1. shallow and moist (almost saturated)
2. weak diurnal cycle in temperature
3. smll frictional effects

Question 9

The Continental boundary layer is
1.
2.
3.

Answer 9

1. Deep mixed layer
2. Strong diurnal cycle in temperature
3. more frictional effects

Question 10

What are the steps in sea breeze circulation
1.
2.
3.

Answer 10

1. Daytime heats air over the land
2. The warming creates outgoing upper level wind due to expanding air/ pressure gradient. layer is thicker due to warming
3. onshore Surface level wind develops due to pressure gradient

Question 11

Describe the sea-breeze circulation

Answer 11

cool moist onshore flow - weaker return flow. arrives like a cold-front. Night time effect is the reverse

Question 12

Define apparent temperature. formula?

Answer 12

The temperature you feel due to heat loss and calm winds etc.

AT = T + 0.33e - 0.7u - 4 where e = vapour pressure (humidity) and u = wind speed

Question 13

Convection occurs when sea breezes___

Answer 13

collide. so look for the collision of winds on a map to show where the convection and most likely condensation will occur

Question 14

What is the “lake effect”?

Answer 14

cold air flowing over relatively warm water. latent and sensible heat fluxes from the water induce heating, evaporation and moistening of boundary. increase instability

Question 15

What are the three types of topographic flows?

Answer 15

1. anabatic - valley to mountain. katabatic - mountain to valley.
2. Blocked flows
3. Orographic flow/precipitation

Question 16

What are blocked flows?

Answer 16

Flow in which the mountains act as barriers to the flow and can form complicated wave like patterns. controls are: mountain height and geometry as well as atmospheric conditiosns. Froude number indicates flow.

Question 17

What is Froude Number?

Answer 17

Fr = U/Nh U = wind speed, N is stability, h is mountain height. if Fr is large -> flow over regime if Fr is small -> flow around regime (blocked flow)

Question 18

What is Orographic precipitation?

Answer 18

A parcel of air is forced over a mountain, water vapour condenses, forms clouds, precipitates out. air warms through latent heat release, decent promotes adiabatic heating.

Question 19

Does Orographic precipitation always occur?

Answer 19

no, can have low concentration of small droplets (cant precipitate into rain) or rapid flow - limited time for droplet collision to form larger droplets.

Question 20

Describe the effect apparent temperature has in terms of global warming if there is:

1. strong winds and reduced humidity
2. strong winds and slightly more humidity
3. slower winds with greater humidity

Answer 20

1. apparent temperature would be lower than actual temperature
2. apparent temperature and actual temperature would be relatively the same
3. apparent temperature would be warmer than actual temperature

Question 21

What happens in atmospheric blocking?

Answer 21

Low and high pressure systems create omega pattern.

flooding in low pressure and heatwaves in high pressure areas