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#2. ELR is 1°C/100m
The ELR now matches the DALR meaning that dry parcels will be neutral. And no vertical movement
DALR = ELR > SALR.
#3. Why does air cool as it rises?
if a parcel of air was forced to rise in the atmosphere, the decreasing ambient pressure would cause the parcel to expand, much like an air bubble does when it rises through a champagne glass. As the air rises and expands, it will cool adiabatically.
#5. The rate of cooling of ascending saturated air is less than the rate of cooling of ascending unsaturated air because:
when air rises, it cools, but as it cools, condensation takes place which releases latent heat to the air parcel
Saturated air lapse rate is0.6°C per 100 m (1.8°C/1000 ft).
unsaturated or dry air has lapse rate 1°C per 100 m (3°C/1000 ft)
#6. The temperature at the surface is 15°C, the temperature at 1000m is 13°C.Is the atmosphere
If the ELR is less than 0.6°C / 100 m,(6°c /1000m) the air is stable – absolute stability.
Stable weather Bad visibility Nil to Light turbulence Stratiform cloud Intermittent to continuous precipitation DZ, -RA, RA, SN
here the lapse rate is 2°c / 1000m
hence stable
#7. Which of the following gives conditionally unstable conditions when saturated?
If the ELR is between 0.6°C and 1°C/100 m, the air is stable if dry and unstable if satu-rated – conditional instability.
#8. A mass of unsaturated air is forced to rise till just under the condensation level. It then settles back to its original position
If an unsaturated parcel of air rises (either because it’s buoyant or it is forced to do so) it will cool adiabatically. This cooling increases the relative humidity of the parcel of air until eventually the temperature of parcel has reached dew point temperature and the relative humidity will be 100%.At this point the air parcel is saturated and further ascent and cooling will cause condensation and cloud to form. The level in the atmosphere at which this happens is called the condensation level. It usually marks the base of any cloud formations
but his all happens when it reaches the condition level
in this case it doesn’t reach the condensation level and descends back to its original position
If the lifted air’s lapse rate (either dry or saturated) is the same as the environmental lapse rate then we have neutral stability. This is because the temperature change of the lifted air will be the same temperature change as the environmental air. Therefore, at every level the air is forced to rise, it will have the same temperature as the surrounding air and therefore the same density. As a result the air will remain where it is displaced to.
#9. What happens to the stability of the atmosphere in an inversion? (Temp increasing with height)
Air is stable whenever the ELR is less than 0.6°C/100m.
In inversion ELR is less than 0.6°C/100m.as temp increases with height
#10. What happens to stability of the atmosphere in an isothermal layer? (Temp constant with height)
Air is stable whenever the ELR is less than 0.6°C/100m.
In isotherm ELR is equal to 0 .as temp remains same
#11. What is the effect of a strong low level inversion?
Vertical windshear is change in wind velocity with height. It is typically measured in knots per 100ft. This type of windshear is very common during an inversion, therefore expect them at night and in well developed high pressure systems such as those found under the sub tropical high pressure belt. As an aeroplane fly’s through an inversion, not only will the change of temperature cause the engine performance to change, but the abrupt change in wind speed and direction may significantly alter the flight path.
#12. A layer of air can be
if dry air is disturbed it will return to is original position, in other words the air is stable, however, when saturated air is disturbed it will continue to rise and it is unstable.
#13. What happens to the temperature of a saturated air mass when forced to descend?
Saturated air that is either forced to rise or descend within the atmosphere will change its temperature, on average by 0.6°C per 100 m (1.8°C/1000 ft).
The SALR varies strongly with the moisture content, which when saturated, depends on temperature, and pressure of the air parcel.
dalr temp will increase 1°C per 100 m , it will heat up more than salr
#14. In still air a lapse rate of 1.2°C/100m refers to:
Elr is not a fixed value
where as
Saturated air lapse rate is0.6°C per 100 m (1.8°C/1000 ft).
unsaturated or dry air has lapse rate 1°C per 100 m (3°C/1000 ft)
#15. What happens to the temperature of a saturated air mass when descending?
Saturated air that is either forced to rise or descend within the atmosphere will change its temperature, on average by 0.6°C per 100 m (1.8°C/1000 ft).
The SALR varies strongly with the moisture content, which when saturated, depends on temperature, and pressure of the air parcel.
dalr temp will increase 1°C per 100 m , it will heat up more than salr
#16. The DALR is
Elr is not a fixed value
where as
Saturated air lapse rate is0.6°C per 100 m (1.8°C/1000 ft).
unsaturated or dry air has lapse rate 1°C per 100 m (3°C/1000 ft)
#18. During an adiabatic process heat is
an adiabatic process is a process in which no heat is transferred to or from a working fluid.
#21. In an air mass with no clouds the surface temperature is 15°C and 13°C at 1000m. This layer of air is:
If the ELR is less than 0.6°C / 100 m,(6°c /1000m) the air is stable – absolute stability.
Stable weather Bad visibility Nil to Light turbulence Stratiform cloud Intermittent to continuous precipitation DZ, -RA, RA, SN
here the lapse rate is 2°c / 1000m
hence stable
#22. The stability in a layer is increasing if
If upper part has warm air that means temperature is increasing with height
and
If the ELR is less than 0.6°C / 100 m, the air is stable – absolute stability
here we have negative elr
#23. When warm air is advected in the lower part of a cold layer of air:
If upper part has cold air that means temperature is decreasing with height
and
If the ELR is greater than 1°C/100 m, the air is unstable – absolute instability.