Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Part 3 Climatology > NZ Airport Climates > Flashcards

NZ Airport Climates Flashcards

1
Q

What are the orographic influences at Auckland? What are their effects? (2)

A
  • Coromandel Ranges to the east: shelter the easterly preventing low cloud bases and precipitation
  • Waitakere Ranges to the north west: Influence the W/ SW wind
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the orographic influences at Wellington? What are their effects? (2)

A
  • North Is. and South Is. high ground create channelling through strait: prevailing wind is NNW or SSE
  • Hills East and West of runway: additional channelling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the orographic influences at Christchurch? What are their effects? (4)

A
  • Port hills 15km SE or airport at 2000ft
  • Southern Alps 90km to the West
  • Canterbury plain is large and flat
  • Wind is normally affected most by alps and cook strait
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the characteristics of the surface wind at Auckland? (7)

A
  • SW and NNE are most common
  • SW occurs more in spring summer
  • NE is evenly spread
  • When strength is 20kts + it is probably SW direction.
  • Sustained 30kts + is normally due to post cold front streams
  • Gustiness not common (50kts + only 2 days per year)
  • Southern edges of TC move through from NW to SE: winds start NE, then E, and then SE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the characteristics of the surface wind at Wellington? (5)

A
  • 98% is N or S direction
  • Due to complex terrain winds do not necessarily follow gradient above friction layer
  • Northerly winds associated with troughs or depressions moving east, most common in spring/ early summer. The accompanying cold front is always preceded by strong NW winds (50-60kts)
  • Southerly winds associated with ridges of high pressure over South Is. or over/ to the east of North Is. (very strong)
  • Sudden winds occurs when a squall line passes. light N winds can be replaced by strong S winds 50kts. Usually short lived (30-40min)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the characteristics of the surface wind at Christchurch? (6)

A
  • NE or E is most common
  • Most frequent in summer due to the sea breeze
  • When 3000ft wind is NNW to NNE, the surface wind will be ENE - most common when high is E or SE of Canterbury
  • NW wind sis hot, dry föhn wind with turbulence - most likely ahead of cold fronts from the SW
  • When 3000ft wind between SSE and SW, surface wind will be SW direction
  • Winds in excess of 20kts occur 3% or year. slightly less than half blow from S/SW with rest from NW or NE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the characteristics of the sea breeze at Auckland? (4)

A
  • Main direction is SSW and most common Oct-Mar
  • Average speed 5-10 kts
  • SE wind will strengthen breeze up to 20-25 kts, and increase vertical extent to 3000ft
  • NE wind will weaken the breeze and make it thin. (Strong shear between 5-600ft)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the characteristics of the sea breeze at Wellington? (7)

A

-Generally Oct-Apr
-Normally SSE with strength of 6-12kts
-Good heating required overland in anticyclonic conditions
-Very small pressure differential is essential
-Normally between 0900-1800 but smaller window during autumn and spring
-Not uncommon to have southerly sea breeze at one end and a light northerly wind at the other
-If wind above friction layer is E/NE, breeze will strengthen to 12-14kts.
Shielding of Rimutakas and Tararuas to the E/NE will assist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the characteristics of the sea breeze at Christchurch? (5)

A
  • Strongest Oct-Apr
  • Requires weak pressure gradient
  • Strength is 15kts
  • Direction is NNE
  • Established 1-2 hrs after sunrise, peaks 1 hr later and weakens 1-2 hrs after sunset
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the characteristics of the Land breeze in Auckland? (3)

A
  • Common in summer and winter, but starts late run winter
  • Blows from E/NE
  • 5-10kts starting about midnight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the characteristics of the land breeze at Wellington? (4)

A
  • Needs weak pressure gradients
  • Light NNE blows year round at night
  • Katabatic effects from N/ NE influence the strength as well as time of day
  • Not unusual for land breeze in winter from mid afternoon onwards.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the characteristics of the land breeze at Christchurch? (4)

A
  • Needs weak pressure gradient
  • Occurs on clear nights
  • Katabatic flow from alps a common factor
  • Starts 1-2 hours after sea breeze has subsided
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the turbulence characteristics of Auckland? (2)

A
  • Surface friction turbulence not normally present

- Thermally induced turbulence is often experienced in and around nearby hills

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the turbulence characteristics of Wellington? (4)

A
  • In Northerly: Throughout approach and landing phase, and from takeoff to 3000ft
  • In southerly: turbulent approach with smooth landing phase, little-none shortly after becoming airborne. smooth on climb out
  • Low level severe turbulence can occur when cook strait wind is SW-NNW. Strong shear at 500-1000ft
  • Degree of turbulence is directly proportional to the amount of fluctuation in wind direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the turbulence characteristics of Christchurch? (5)

A
  • Relatively little when prevailing Easterly
  • Turbulence if sea breeze turns to NW’er
  • NW can have very strong low level shear with mod-sev turbulence
  • Established NW will have turbulence down to ground
  • Convective heating can create localised moderate turbulence and Cb and associated hail.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the characteristics of fog at Auckland? (6)

A

-Radiation fog common Apr-Aug when a high prevails
-Prevailing wind will affect onset and persistence of fog
-Generally form 0300 and gone by 0900, may be slower when thicker fog
-Less of a problem when winds blow from the NNE
-When wind is W/ NW more likely to form fog, forms around 2200 and is difficult to predict duration.
-Substantial fog can remain over Papakura Chanel
When gentle sea breeze sets in from SW the fog can reform and last all day

17
Q

Describe the characteristics of fog at Wellington? (4)

A
  • Very uncommon - 5 days per year
  • Normally sea fog from South Is. east coast in S wind
  • Most occurrences are Jan-Mar
  • Radiation fog from Hutt valley can very rarely be blown to airport in light NE wind
18
Q

Describe the characteristics fog at Christchurch? (6)

A
  • Quite common - 45 days per year
  • Radiation type most common
  • Clear nights with weak pressure gradient, NE wind drops to >5kts and changes to light NW
  • Evening fog will clear around midnight and reform before sunrise
  • Advection fog can form over Pegasus Bay or Waimakariri river to North but will lift slightly off the surface
  • Advection fog off lake ellesmere less likely to lift off surface but also less common
19
Q

What are the characteristics of low cloud formation at Auckland? (3)

A
  • Most common cause is moist NE airstream (500-600ft, sometime 300ft) - will last 24 hours
  • Slow moving or stationary front with moist NNE flow in advance may have 300ft cloud with persistent heavy rain lasting 12 hours
  • Rain from the SW/W is usually due to passage of wave depression or low pressure lying to S/SE of AA, so Cb and low bases expected
20
Q

What are the characteristics of low cloud formation at Wellington? (6)

A
  • Moist southerly with light or moderate strength (most restrictive)
  • Low to the N/NE with high over Canterbury (not large pressure difference)
  • Weakening tropical depression down east coast of North Is.
  • Moist northerly will cover cook strait but terrain will shelter airport
  • Can produce wave effect on lee side-not uniform
  • If northerly flow is due to front/trough to the west low cloud will form on approach side of runway, with strong wind, rain and poor vis.
21
Q

Describe the characteristics of low cloud formation at Christchurch? (6)

A
  • High pressure ridge to E/SE
  • Easterly drift advects low cloud/fog from ocean & pegasus bay (200-300ft bases)
  • Depression to E/NE
  • Surface wind SW overland and SE over sea with cloud base to normally 1000-1500ft, due to shielding from banks peninsula
  • Occurs after passing cold fronts
  • SW winds 1000ft bases can be present, lower to the E around port hills.
22
Q

What conditions can affect visibility at Auckland? (4)

A
  • Low cloud: No problems in summer, High frequency May-Aug
  • N - NE winds >20kts normally cause
  • Showers can cause, short duration during a front
  • Pollution when winds light and air is stable
23
Q

What conditions can affect visibility at Wellington? (5)

A
  • Low cloud: generally southerly with strength >20kts
  • Jan-Mar has poorest conditions
  • May-Jul generally optimal
  • Precipitation less likely to cause than low cloud
  • Heavy showers can reduce to 1000-3000m for short period
24
Q

What conditions can affect visibility at Christchurch?

A
  • No change in NW or SW winds
  • E/NE or SSW winds >20kts will reduce vis
  • Low cloud and drizzle will significantly reduce
  • 20+kts from S/SW can bring low cloud and poor vis
  • May-Sep have highest incidence of low cloud or reduced vis.

Part 3 Climatology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions