Results
#1. In S hemisphere if an observer faces wind, low will be to his ____
Buys Ballot’s Law states that: If an observer stands with his back to the wind, the lower pressure is on his left in the northern hemisphere, and on his right in the southern hemisphere.
A corollary of this law is that if an aircraft is experiencing starboard drift in the northern hemisphere the aircraft is heading towards low pressure
#2. In N hemisphere due to rotation of earth winds are deflected to
Due to rotation of earth from west to east the wind is constantly deflected to its right in northern hemisphere
#3. Local Winds follow Buys Ballots law
local winds like fohn winds katabatic anabatic are formed due to convective activity, they do not follow buy ballots
#4. Coriolis force acts perpendicular to the _____ of wind direction in N hemisphere.
It acts 90° to the wind direction causing air to turn to the right in the northern hemi-sphere and to the left in the Southern hemisphere. CF is maximum at the poles and minimum at the equator.
#5. Geostrophic wind is due to the balance between the forces
The Geostrophic Wind blows parallel to straight isobars
Balance between pressure gradient force and coriolis
#6. Coriolis force is strongest at
CF is maximum at the poles and minimum at the equator.
#7. Geostrophic rule breaks down at
Geostrophic force is a function of sin , sin 0° = 0
At equator latitude is 0°
#8. Fohn winds are ____ on the Leeward side of a mountain.
Föhn Wind is a warm dry wind which blows on the downwind( leeward) side of a mountain range.
#9. The wind sliding down a hill during night is called ______ wind.
Föhn Wind is a warm dry wind which blows on the downwind( leeward) side of a mountain range.
A katabatic wind (which simply means “going downhill”), is a wind that blows down-slope, for example, down hills or mountains. However, there is a difference between winds that feel warmer (FOHN) than their surroundings and those that are cooler than their surroundings
#10. With the onset of sea breeze there is a _____ in temperature and ____ in RH.
On a sunny day, particularly in an anticyclone with a slack pressure gradient, the land will heat quickly.
The air in contact will be warmed and will rise and expand so that pressure at about 1000 ft will be higher than pressure at the same level over the sea. This will cause a drift of air from over the land to over the sea at about 1000 ft. The drift of air will cause the surface pressure over the land to fall, and the surface pressure over the sea to rise.
As a result there will be a flow of air over the surface from sea to land – a sea breeze. the winds is from sea it will be moist and cold compared to land
Sea breeze day
Land breeze night
#11. Sea breeze sets in by ______ and dies off at _____
Sea breeze day
Land breeze night
#12. If an aircraft in N-hemisphere flies from H to L it will experience
Buys Ballot’s Law states that: If an observer stands with his back to the wind, the lower pressure is on his left in the northern hemisphere, and on his right in the southern hemisphere.
A corollary of this law is that if an aircraft is experiencing starboard drift in the northern hemisphere the aircraft is heading towards low pressure.
#13. In N-Hemisphere if you experience Port drift, altimeter will read
Buys Ballot’s Law states that: If an observer stands with his back to the wind, the lower pressure is on his left in the northern hemisphere, and on his right in the southern hemisphere.
A corollary of this law is that if an aircraft is experiencing starboard drift in the northern hemisphere the aircraft is heading towards low pressure.
port drift towards high pressure
when you fly from low to high you underread
LOW HIGH LOW
#14. Lines of constant wind speed drawn on weather charts are called
Tach relates to speed
#15. Squall are distinguished from gusts by:
A gust is a sudden increase in wind speed, often with a change in direction
A squall is a sudden increase in wind speed, often with a change in direction. It lasts for some minutes and can cover a wide area
#16. The thermal wind is:
The pressure changes that exist in the upper atmosphere that control our upper winds are directly related to the temperature differences between air masses
Thermal wind in a layer is defined as the wind which must be vectorally added to Geostrophic wind at lower level, to obtain Geostrophic wind at upper level
#17. On a weather map if isobars are closely packed, the surface winds are likely to be
Closely spaced isobars would indicate a large pressure gradient force. This is common in low pressure systems
The Pressure Gradient Force, (PGF), controls the windspeed
#18. Anabatic wind occurs
On a warm sunny day, the slope of a hill will become heated by insolation, particularly if it is a south facing slope.
The air in contact with the ground will be heated by conduction and will rise up the hill. Free cold air will replace the lifted air and so a light wind will blow up the hillside. An anabatic wind is a light wind of around 5 kts which blows up a hill or mountain by day.
#19. Anabatic wind is stronger than katabatic
The air in contact with the ground will be heated by conduction and will rise up the hill. Free cold air will replace the lifted air and so a light wind will blow up the hillside. An anabatic wind is a light wind of around 5 kts which blows up a hill or mountain by day.
#20. Katabatic wind is down slope cold wind due to nocturnal cooling
A katabatic wind (which simply means “going downhill”), is a wind that blows down-slope, for example, down hills or mountains. However, there is a difference between winds that feel warmer than their surroundings and those that are cooler than their surroundings
#21. Katabatic wind occur due to sinking of cold air down the hill slope
A katabatic wind (which simply means “going downhill”), is a wind that blows down-slope, for example, down hills or mountains. However, there is a difference between winds that feel warmer than their surroundings and those that are cooler than their surroundings
#22. Anabatic wind occur due to downward movement of air along valley
On a warm sunny day, the slope of a hill will become heated by insolation, particularly if it is a south facing slope.
The air in contact with the ground will be heated by conduction and will rise up the hill. Free cold air will replace the lifted air and so a light wind will blow up the hillside. An anabatic wind is a light wind of around 5 kts which blows up a hill or mountain by day.
#23. Sea breeze is stronger than land breeze
Sea Breezes On a sunny day, particularly in an anticyclone with a slack pressure gradient, the land will heat quickly.
The air in contact will be warmed and will rise and expand so that pressure at about 1000 ft will be higher than pressure at the same level over the sea. This will cause a drift of air from over the land to over the sea at about 1000 ft. The drift of air will cause the surface pressure over the land to fall, and the surface pressure over the sea to rise.
On average, sea breezes extend 8 to 14 nm either side of the coast and the speed is about 10 kts. In the tropics speed is 15 kts or more and the inland extent is greater.
———————
Land Breezes After sunset the situation will reverse. The land will cool rapidly whilst the sea will retain its heat. There will be an increase in pressure at the surface over the land whilst the pressure over the sea will fall – there will be a land breeze. The speed will be about 5 kts and the breeze will extend about 5 nms out to sea. This effect is shown below.
#24. The wind blows clockwise around a low in N-hemisphere
In the Northern Hemisphere, the deflection of the moving air mass, is to the right, causing winds to blow anti-clockwise around the depression. In the Southern Hemisphere the deflection is to the left, and so, South of the Equator, the wind blows clockwise around a depression. This deflection of the moving air mass is caused by a force known as the Coriolis Force.
#25. The wind blows clockwise around a low in S-hemisphere
In the Northern Hemisphere, the deflection of the moving air mass, is to the right, causing winds to blow anti-clockwise around the depression. In the Southern Hemisphere the deflection is to the left, and so, South of the Equator, the wind blows clockwise around a depression. This deflection of the moving air mass is caused by a force known as the Coriolis Force.
#26. The wind blows anticlockwise around a low in N-hemisphere
In the Northern Hemisphere, the deflection of the moving air mass, is to the right, causing winds to blow anti-clockwise around the depression. In the Southern Hemisphere the deflection is to the left, and so, South of the Equator, the wind blows clockwise around a depression. This deflection of the moving air mass is caused by a force known as the Coriolis Force.
#27. The wind blows anticlockwise around a low in S-hemisphere
In the Northern Hemisphere, the deflection of the moving air mass, is to the right, causing winds to blow anti-clockwise around the depression. In the Southern Hemisphere the deflection is to the left, and so, South of the Equator, the wind blows clockwise around a depression. This deflection of the moving air mass is caused by a force known as the Coriolis Force.
#29. Due to friction, from day to night for an isobaric pattern (in N hemisphere) the surface wind backs and weakens
Friction between moving air and the land surface will reduce wind speed near the ground. This reduction also reduces the CF. This will cause the two forces in the Geostrophic Wind to be out of balance since now CF is less than PGF. The wind is now called a surface wind
#30. The wind which spirals inward counter-clockwise in the N Hemisphere are associated with
In the Northern Hemisphere, the deflection of the moving air mass, is to the right, causing winds to blow anti-clockwise around the depression. In the Southern Hemisphere the deflection is to the left, and so, South of the Equator, the wind blows clockwise around a depression.
#31. Lower level wind 05010 kt, upper level wind 23005 kt, what is the thermal wind
Lower level wind = 050/10 kt =(-230/10)
upper level wind = 230/05 kt
thermal wind = ?
lower level wind plus thermal wind = upper level wind
050/10kt plus Thermal wind = 230/05 kt
or
-230/10kt plus T.W = 230/05
t.w = 230/05 plus 230/10
= 230/15
#32. A change in wind direction from 310° to 020° is
Since direction is changing in clockwise direction it is veering
#33. A change from 270° to 250° is
Direction changing clockwise hence backing
#34. Sudden change in wind speed form 10kt to 30kt an then 15 kt are
A gust is a sudden increase in wind speed, often with a change in direction. It lasts only for a few seconds and is very local.
A gale is a condition where the wind speed exceeds 33 kt, or if the wind gusts exceed 42 kt.
#35. Sudden change in wind speed from 10 kt to 30 kt for 2 -3 minutes
A gale is a condition where the wind speed exceeds 33 kt, or if the wind gusts exceed 42 kt. Stays for 2-3 minutes
#36. A significant wind shear is generally associated with TS or line squall
Thunderstorm causes large changes in the direction and speed of the wind in the vicinity of the cloud, both vertically and horizontally, and may, thus, give rise to dangerous low level wind shear.
#37. Cyclostrophic wind gives a good approximation of the 2000′ wind in an intense tropical storm
Cyclostrophic wind is defined as the wind which is markedly curved and blows due to the balance between pressure gradient and cyclostrophic force ,near the centre of a tropical revolving storm or in a circular tornado , the equation gives a close approximation to the actual wind
#38. Rotor clouds have extremely turbulent flying conditions
If the winds approaching a mountain range are strong only at lower levels and fall off or reverse direction at higher levels, Rotor Streaming may result
#39. Friction causes winds to flow cross isobaric by _____ over land and ____ over sea
#40. If the S is warmer than the N, level by level, from surface up to higher levels, then the ____ wind will strengthen with height with no change in direction in N hemisphere.
The temperature in the troposphere decreases from equator towards the polls therefore the thermal wind throughout the troposphere blows from west and the westerly component increases with height
#41. Gradient wind is ____ of the geostrophic wind in an anticyclone
The gradient wind speed around a depression is less than the geostrophic wind for the same isobar interval. Hence if the Geostrophic Wind Scale (GWS) is used, it will overread.
#42. Gale is
A gust is a sudden increase in wind speed, often with a change in direction. It lasts only for a few seconds and is very local.
A gale is a condition where the wind speed exceeds 33 kt, or if the wind gusts exceed 42 kt.
#43. In N hemisphere thermal wind is parallel to ____ with low value to left
Thermal wind is a fictitious wind which blows parallel to the thickness(isotherm) line keeping low thickness on the left in the northern hemisphere
#44. The inertial flow is
#45. Upper level wind is 24025 kt, lower level wind is 06015 kt, the thermal wind is?
Lower level wind = 060/15 kt =(-240/15)
upper level wind = 240/25kt
thermal wind = ?
lower level wind plus thermal wind = upper level wind
060/15kt plus Thermal wind = 240/25 kt
or
-240/15kt plus T.W = 240/25
t.w = 240/25 plus 240/15
= 240/40