Jun 25, 2009, 09:07 PM
I am looking for answers to these questions. If anyone could help answer this, I would appreciate it a lot...thanks

1. Under what atmospheric condition is the actual mixing ratio equal to the saturation mixing ratio?

2. Is it possible for thunderstorms to form if the lower troposphere is conditionally stable? Explain your answer.

3.Two otherwise identical air parcels, the first having a lower water vapor content than the second, are lifted from the same altitude. Which parcel would first experience condensation or deposition of water vapor? Why?

4.In winter at middle latitudes, the relative humidity is typically lower in a house than outside whereas the absolute humidity is usually higher in a house than outside. Explain this observation.

5.Outdoor air at 0 C (32 F) and relative humidity of 90% is brought indoors and heated to 20 C (68 F). Compute the relative humidity of the indoor air.

6.An unsaturated air parcel initially has a temperature of 0 C (32 F). Assuming that the relative humidity remains less than 100%, predict the temperature of the parcel after it is lifted 2500 m (8200 ft).

7.Determine whether the following soundings are stable, unstable, or neutral for both saturated and unsaturated air parcels.
{a} +10 C/1000 m {b} 5 C/1000 m {c} 8 C/1000 m
{d} −10 F/1000 ft {e} +1 F/1000 ft {f} −13 C/1000 m

alexweather19
Sep 25, 2009, 07:28 PM
1) This would be total saturation (RH = 100%).

2)Yes, it is possible; for moist air parcels. Moist air parcels cool at a smaller rate, then dry air parcels due to the release of latent heat during condensation. Essentially, if you get a moist air parcel, that has enough positive buoyancy, you can get thunderstorm development. To be conditionally stable means that the atmosphere is unstable for moist air parcels and stable for dry air parcels.

3)The parcel with the higher amount of water vapor would experience condensation or deposition of water vapor at a lower altitude compared to the parcel with the least water vapor. When it comes to condensation of water vapor, the amount of water vapor matters. The more water vapor in a parcel, the sooner it will condense and the less water vapor in a parcel, the more lifting that will be needed to cause condensation.

4) Relative humidity depends solely on the actual amount of moisture and temperature. If bring air in from outside during the winter and therefore increase the temperature, you also increase the amount of water vapor needed for saturation. Absolute humidity on the other hand depends solely on moisture and the volume of dry air it occupies, as it's the ratio of the actual amount of water vapor per unit volume of dry air. So the relative humidity is lower inside a house and higher outside the house due to the dependence on the temperature. The absolute humidity is higher in the house then it is outside, because again it solely depends on the amount of moisture and the volume of dry air that moisture occupies.

5) There is a trick to this. For every 10 degrees C in temperature increase, the relative humidity gets divided in half. So if you increase the temperature by 20 degrees C, then you would take (1/4)*(.90) = 0.225 = 22.5%

6) Since the relative humidity of the parcel remains below 100%, then you can lift the parcel dry adiabatically as such:

Dry Adiabatic Lapse Rate = -9.8 degrees C/1000 m

Since our change in elevation is 2500 m, then we multiply -9.8 degrees C by (2500 m/1000m) = -9.8 degrees C *2.5 = -24.5 degrees C

Therefore add the original temperature and the temperature change together:

0 degrees C - 24.5 degrees C = -24.5 degrees C<---Answer

7) a. Stable for dry and moist air parcels.

B. Stable for dry air parcels, neutral for moist air parcels.

C. Stable for dry air parcels, unstable for moist air parcels.

D. Unstable for both dry and moist air parcels.

E. Stable for both dry and moist air parcels.

F. Unstable for both dry and moist air parcels.