Earth Science- Clouds?

Question

1. why does the height of a cumulus cloud base change from day to day?

2. what would happen to the height of a cloud base id the dewpoint temperature was lower?

3. how would it be possibel to have a day without any clouds?

4. what relationship would you expect to find between the air temp and the dewpoint temp at ground level if the area is covered by fog?

5. what happens to the air temp of a descending mass of air?

6. what happens to the dewpoint temp of a descending mass of air?

7. explain why a descending mass of air would become drier.

8. descirbe how you can determine the base altitude at which clouds form.


PLEASE HELP- I DO NOT UNDERSTAND! THX

Answer 1

1) Because the difference between temperature and dewpoint changes from day to day.
2) The dewpoint temperature doesn't influence the height of the clouds but the difference between dewpoint and temperature does.
3) In a high pressure, air sinks and by adiabatic effect, warms up and all clouds dissipate.
4) In fog, dewpoint temperature is the same as temperature. This is the old seafarer's wet & dry bulb thermometer.
5) It warms up by adiabatic effect (gas compression).
6) The dewpoint stays the same as it is an indication of the relative humidity of the air.
7) The air doesn't become dryer as such. The absolute value stays the same but the relative humidity will be lower and the air feels dryer. E.g. at 15°C, air can sustain about 14 gr. of water per cubic meter. The relative air humidity is then 100% and at dewpoint. If the sinking air warms up by adiabatic effect, it will still be 14 gr. but the relative humidity will be less than 100%.
8) If you know the air temperatue and dewpoint, as you can if you read aviation METAR reports, from that difference and using an average of 2°C per 1,000 ft, you can calculate the base of the clouds. Say, if the temperature is 10°C and dewpoint 6°C, then the ceiling will be roughly at 2,000 ft. Of course, that isn't true in e.g. an inversion where warmer air is above colder air as you may experience in a high pressure very early in the morning when surface temperature is cooler than above.

Answer 2

Height Of Cumulus Clouds

Answer 3

to start...yes. ONe is related to the other. We get moisture in the air from evaporation of water molecules which as a gas rise. Then when they get to a certain temp they condensate into clouds and then when they can't hold any more water...rain.

Answer 4

1 - depends on condensation level