Trouble with ELR and stability of the air.

[dlcmdrx]

Im having trouble understanding this topic.


So instability occurs when ELR bigger tan DALR.


That means ELR cools faster tan 3 per 1000 correct?


But how is that posible knowing that for air to rise has to be warmer than its surroundings.


I mean if lets says ELR is 3.5 this is gonna be stable because it is cooling at a faster rate and therefore would sink again right?


But everybody says that would be unstable air, which i dont understand.


What i am trying to say is that in this video at the begining:


https://www.youtube.com/watch?v=iH47K2b7vy4&t=3s


The ELR line for stable conditions should be to the right of the blue line. Because in that case degree of cooling per feet gained in altitude would be very slow making the air keep warmer tan its surroundings and therefore being unstable.

[oggers]

So instability occurs when ELR bigger tan DALR.

Yes. That is absolute instability. Conditional instability (or conditional stability?) is when ELR is between DALR and SALR.

That means ELR cools faster tan 3 per 1000 correct?


Yes, in the case of absolute instability.

But how is that posible knowing that for air to rise has to be warmer than its surroundings.


The ELR is that of the surrounding air.


I mean if lets says ELR is 3.5 this is gonna be stable because it is cooling at a faster rate and therefore would sink again right?

The ELR is not the lapse rate of the rising parcel of air. It is the lapse rate of the airmass. It is what you get when you measure the temp of the airmass at different levels as opposed to the lapse rate you get if you track the temp of a parcel of air as it rises through the airmass.

The parcel of air that begins to rise may cool at the DALR or SALR dependent upon whether it reached its dew point temp. Whatever, if the ELR is greater than the lapse rate of the rising parcel, then the parcel will be warmer than the surrounding air at each new level it passes through by an increasing amount the further it rises. So it will keep going up.

[Piltdown Man]

The ELR depends on the history of the bits of air that makes up the vertical column of air in question. The ELR will not be constant. But the little parcel of air that has just become unstable at ground level hasn't a clue what it is about to travel through. All it will do is reduce its temperature as it rises and it will always rise whenever it is warmer than the surrounding air. How far and how quickly it will rise will depend on the air that surrounds it.

PM