Adiabatic vs Ambient Lapse Rate?

[CC268]

For some reason I am having difficulty understanding the difference between these two.

"The adiabatic lapse rate is the rate at which the temperature of a rising or falling air mass lowers or increases per distance of vertical displacement. The ambient or environmental lapse rate is the temperature change in the (non-displaced) air per vertical distance"

I'm not sure why but the above explanation is confusing to me.

 

[Clark1961]

Not a course. Ed does 'splain things fairly well IMNSHO.

 

[CC268]

Not a course. Ed does 'splain things fairly well IMNSHO.

Thanks will check it out. Im going to post a separate thread about potential weather courses and leave this question by itself. I think that will work better.

 

[Hank S]

It's simple. (Disclaimer--I'm an engineer.)

As a parcel of air rises, it cools. This is adiabatic cooling. Same when the parcel falls, except temperature rises. Adiabaticly.

When the atmosphere is stable, neither rising or falling parcels of air, temperature also decreases with altitude. This is ambient cooling.

The "rates" of both are generally expressed as so many degrees per 1000 feet.

Simple, as long as you understand the basic concept of rising / falling parcels of air and stable atmosphere. Don't get hung up on the book's wonky explanations, many of which are written more for the author to show off his vocabulary than to quickly impart needed information.

 

[CC268]

It's simple. (Disclaimer--I'm an engineer.)

As a parcel of air rises, it cools. This is adiabatic cooling. Same when the parcel falls, except temperature rises. Adiabaticly.

When the atmosphere is stable, neither rising or falling parcels of air, temperature also decreases with altitude. This is ambient cooling.

The "rates" of both are generally expressed as so many degrees per 1000 feet.

Simple, as long as you understand the basic concept of rising / falling parcels of air and stable atmosphere. Don't get hung up on the book's wonky explanations, many of which are written more for the author to show off his vocabulary than to quickly impart needed information.

Yea I am an engineer too...took Thermo 1 and Thermo 2 so I suppose I should understand wikipedia's explanation, but I found it confusing lol. I guess I am a stoopid engineer . Your explanation makes more sense and I understand now. Thanks. And actually now that you've explained it I understand Wikipedia's explanation ha

 

[Hank S]

Yea I am an engineer too...took Thermo 1 and Thermo 2 so I suppose I should understand wikipedia's explanation, but I found it confusing lol. I guess I am a stoopid engineer . Your explanation makes more sense and I understand now. Thanks. And actually now that you've explained it I understand Wikipedia's explanation ha

See? wiki is showing off!

 

[Lon33]

It's simple. (Disclaimer--I'm an engineer.)

As a parcel of air rises, it cools. This is adiabatic cooling. Same when the parcel falls, except temperature rises. Adiabaticly.

When the atmosphere is stable, neither rising or falling parcels of air, temperature also decreases with altitude. This is ambient cooling.

The "rates" of both are generally expressed as so many degrees per 1000 feet.

Simple, as long as you understand the basic concept of rising / falling parcels of air and stable atmosphere. Don't get hung up on the book's wonky explanations, many of which are written more for the author to show off his vocabulary than to quickly impart needed information.

Even though you are an engineer, you’ve made it “simple” for me too, and I’m not an engineer. Thank you.

 

[BigBadLou]

I agree, they seem to over-explain certain simple concepts.
To my understanding, they use the adiabatic rate to indicate the rate of cooling (usually) of a parcel of air because it needs to be considered as an adiabatic system while it is rising. Not a bad name, IMHO.
The ambient rate is logically meant for the air surrounding the parcel.
Two separate rates, two separate names.
Now the real fun starts when the rates differ greatly.

Understanding lapse rates helped me understand weather oh-so-much better. I too watched the Weather In The Vertical videos and presentations. Good stuff!

 

[Clark1961]

Understanding lapse rates helped me understand weather oh-so-much better. I too watched the Weather In The Vertical videos and presentations. Good stuff!

Ed walks through it very well I think. Sufficient detail without getting lost in minutiae. Orderly progression of theory and then some applied stuff. Great that it’s a free resource.

 

[iamtheari]

Adiabatic lapse rate: The rate at which a parcel of air cools as its altitude changes. This is a constant rate.

Ambient (or actual) lapse rate: The rate at which the temperature of the actual air around you changes as your altitude changes. This rate is not a constant and often varies from one altitude to another, one place to another, and one minute to another.

If you have a parcel of air that is warmer than the surrounding air, it will rise, like a hot air balloon without the canopy or basket to hold it down. On the way up, its own temperature will cool at the adiabatic lapse rate and the temperature of the air around it will change at the ambient lapse rate. When the parcel's temperature is the same as the ambient temperature, it will stop moving. Stable air is already in that state, with no lifting force. Unstable air has a lifting force because the ambient lapse rate is far enough off the adiabatic lapse rate to make it want to rise.

 

[CC268]

Adiabatic lapse rate: The rate at which a parcel of air cools as its altitude changes. This is a constant rate.

Ambient (or actual) lapse rate: The rate at which the temperature of the actual air around you changes as your altitude changes. This rate is not a constant and often varies from one altitude to another, one place to another, and one minute to another.

If you have a parcel of air that is warmer than the surrounding air, it will rise, like a hot air balloon without the canopy or basket to hold it down. On the way up, its own temperature will cool at the adiabatic lapse rate and the temperature of the air around it will change at the ambient lapse rate. When the parcel's temperature is the same as the ambient temperature, it will stop moving. Stable air is already in that state, with no lifting force. Unstable air has a lifting force because the ambient lapse rate is far enough off the adiabatic lapse rate to make it want to rise.

Great explanation as well