Humidity Question?

Question

I have a couple of questions regarding humidity that i need help with. Any help would be great:

1. describe the conditions that allow dew to form, and during which months is dew most likely?

2. Why does 0 degrees celciuswith a 0 degrees celcius dew point feel more uncomfortable that 0 degrees celcius with a -10 decrees celcius dew point?

Answer 1

The main condition required for the formation of dew is that the earth surface should lose more heat energy by infra red radiation than it receives through direct solar radiation.This will be the case when(1) the sky is clear during night(or evening) (2) sufficient relative humidity near the ground(3)Less water vapour in the higher layers of the atmosphere(probably to reduce the greenhouse effect).

When the the air temperature and the dew point temperature(both are 0 degree celcius) are the same, then the atmosphere will be saturated.Hence the air will be sultry and it can not absorb any moisture.So we feel uncomfortable.

But when the air temperature is 0 degree celcius and the dew point tremperature is -10(minus ten) degree celcius,the air will remain unsatured and we feel comfortable as it can absorb any water found on our body.