Meteorology
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Regulations#1. Winds in a low pressure
Winds from high pressure flow towards low pressure to fill the void, so they converge in low pressure.
#2. Low pressure is associated with
Low pressure is associated with rising air, which leads to cloud formation and precipitation.
#3. In a high pressure area winds are
High pressure is associated with stable air and sinking air, which results in weak winds.
#4. Flying from Low to High an altimeter would read
As you fly from low pressure to high pressure, the actual altitude will be lower than what the altimeter indicates (underreading).
#5. Isallobars are lines of equal
#6. What kind of a barometer is an altimeter
An altimeter is an aneroid barometer, which uses a sealed, partially evacuated metal capsule to measure pressure.
#7. A region between two Lows and Two Highs is
A col is a region of relatively low pressure between two highs and two lows.
#8. Bad weather and better visibility is associated with
In a low-pressure area, winds converge, creating upward air movement. With abundant moisture, this is the ideal condition for cloud formation and bad weather. However, due to the movement of air, there is no mist, dust, haze, or stagnation, resulting in good visibility.
#9. The relationship between height and pressure is made use in construction of
Altimeters use the relationship between pressure and altitude to determine the aircraft’s height.
#10. Altimeter always measure the height of aircraft above
#11. The rate of fall of pressure with height in a warm air mass compared to cold air mass will be
Pressure decreases more rapidly with height in cold air compared to warm air.
#12. An increase of 1000 ft at MSL is associated with decrease of pressure of
The actual pressure decrease varies with temperature, but a rough estimate is 1 hPa per 30 ft (or 1 mb per 30 ft). So, for 1000 ft, the decrease would be around 33 hPa.
#13. Lines drawn through places of equal pressure are known as
Lines connecting points of equal pressure are called isobars.
Lines connecting points of equal pressure change (tendencies) are called isallobars.
#14. Which is true?
A trough is a region of low pressure. In the Northern Hemisphere, winds tend to back (turn counterclockwise) around a trough.
#15. Semi-diurnal pressure changes are most pronounced in
Semi-diurnal pressure changes (twice-daily) are most noticeable in the tropics.
#16. In the Southern Hemisphere, around a Low pressure Area wind blows
In the Northern Hemisphere, winds around a low-pressure system circulate in a counterclockwise direction. In the Southern Hemisphere, they circulate in a clockwise direction. This is a fundamental principle of meteorology.
#17. Altimeter of a/c on ground reads aerodrome elevation; its sub-scale is set to
QNH gives altitude above MSL.
QNE gives flight level (based on a standard pressure).
QFE gives altitude above the aerodrome’s elevation.
If you know the aerodrome’s elevation, you can calculate QFE from QNH using the formula: QFE = QNH – (elevation / 8) where the elevation is in meters.
#18. Instrument for recording pressure is called
BARO: Refers to pressure. For example, a barometer measures atmospheric pressure.
ANEMO: Refers to wind. For example, an anemometer measures wind speed.
HYGRO: Refers to humidity or moisture. For example, a hygrometer measures humidity.
#19. Poor visibility is associated with
In a high-pressure system:
Winds diverge: They flow outward in all directions.
There’s little to no vertical movement of air: This creates a stable environment.
Fog, mist, or haze can become trapped: Due to the lack of vertical movement, pollutants and moisture can become trapped near the surface, leading to poor visibility.
#20. On either side, perpendicular to the ______ pressures rise
A ridge is an area of high pressure. Pressures rise on either side of a ridge.
#21. Fall of pressure with height is more rapid in
Cold air is denser, so pressure decreases more rapidly with height in cold areas.
#22. 300 hPa in ISA corresponds to the level
300 hPa in the ISA corresponds to an altitude of approximately 30,000 feet.
#23. 18,000 ft height in ISA corresponds to the pressure level
18,000 feet in the ISA corresponds to a pressure level of approximately 500 hPa.
#24. 200 hPa in ISA corresponds to the level
200 hPa in the ISA corresponds to an altitude of approximately 40,000 feet.
#25. 24,000 ft height in ISA corresponds to pressure level
24,000 feet in the ISA corresponds to a pressure level of approximately 400 hPa.
#26. 700 hPa in ISA corresponds to the Fight level
700 hPa in the ISA corresponds to a flight level of 10,000 feet.
#27. 40,000 ft height in ISA approximately corresponds to pressure level
40,000 feet in the ISA corresponds to a pressure level of approximately 200 hPa.
#28. 850 hPa in ISA approximately corresponds to the height
850 hPa in the ISA corresponds to an altitude of approximately 5,000 feet.
#29. Atmospheric pressure is due to
Atmospheric pressure is caused by the weight of the Earth’s atmosphere. This weight is due to the force of gravity, which pulls the air molecules towards the Earth’s surface.
While wind, temperature, and density can affect atmospheric pressure, they are not the primary cause.
#30. An aircraft is gaining altitude, inspite of altimeter reading constant altitude. Why?
An altimeter underreads when flying from a low-pressure area to a high-pressure area. This is because the pressure at your actual altitude is higher than the pressure the altimeter is calibrated for. Remember the mnemonic “Left, Over, Right, Under” (LORU)Â for wind direction and altimeter readings in the Northern Hemisphere.
#31. An contour of 9160 m can be expected on a constant pressure chart of pressure level
One meter is approximately 3.28 feet. Therefore, 9160 meters equals approximately 30,000 feet. Using the provided chart, a pressure altitude of 30,000 feet corresponds to a pressure of 300 hPa.
#32. In contour chart of 300 hPa, isohypse (contours) are drawn at interval of
GPM (geopotential meters) is the unit used for contour charts. The contours are drawn at intervals of 40 GPM on 700 hPa and 500 hPa level charts and at 80 GPM on 300 hPa and 200 hPa level charts.
#33. In constant pressure chart of 500 hPa, isohypse are drawn at interval of
GPM is unit of contour charts the contours are drawn at an interval of 40 GPM in 700 Hpa and 500 hpa level charts and at 80 GPM in 300 Hpa and 200 Hpa level charts
#34. QNH of an aerodrome 160 m AMSL is 1005 hPa. QFE? Assuming 1hPa = 8m
If you set QNH on your altimeter, you will obtain the altitude above mean sea level (MSL).
If you set QFE, you will get the height of the airfield relative to the aircraft’s position.
In this scenario, the airfield is 160 meters above MSL. If the pressure at sea level is 1005 hPa, the pressure at the airfield (160 meters above) would be:
1 hPa = 8 meters
20 hPa = 160 meters
Therefore, you would subtract 20 hPa from 1005 hPa to get the pressure at the airfield: 1005 hPa – 20 hPa = 985 hPa
Remember, pressure decreases with increasing altitude.
#35. Steep pressure gradient would mean
A pressure gradient is the horizontal rate of change of pressure perpendicular to the isobars, directed from high to low pressure. It is considered steep if the isobars are closely packed and weak if they are far apart.
#36. What type of inversion occurs when a stable layer lies in a high pressure area
In a high-pressure system, as air descends, it becomes compressed. This compression causes the air to warm, preventing significant cloud formation (as clouds form when air cools). This warming also creates a “foot” of abnormally warm air at the bottom of the high-pressure system. This layer of warm air, located a few thousand feet above the surface, creates a temperature inversion commonly known as a subsidence inversion.
#37. Which of the following would cause true altitude to increase when altimeter indicates constant altitude?
If your altimeter is indicating a lower altitude than your actual altitude, it could be due to:
Flying from a low-pressure area to a high-pressure area: This is known as “underreading.”
Flying from a cold air mass to a warm air mass: This can also cause an altimeter to underread.
#38. The movement of wind in relation to a cyclone is
A cyclone is a low-pressure system. In a low-pressure area, winds converge, creating upward air movement. With abundant moisture, this is the ideal condition for cloud formation and bad weather.
#39. An aerodrome is at the mean sea level. Its QNH is 1014.0 hPa. Its QFF will be
QNH is the pressure at the aerodrome’s elevation assuming standard temperature conditions (ISA).
QFE is the pressure at the aerodrome’s elevation assuming actual temperature conditions.
If the aerodrome is at mean sea level: There is no difference in elevation between the aerodrome and MSL. Therefore, QNH and QFE will be the same.
In this case, since the aerodrome is at mean sea level, the QNH (1014.0 hPa) is also the QFE.
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