Old Jun 29th 2009, 09:41 AM   #1
baldingwxguy
Open Line Veteran
 
baldingwxguy's Avatar
 
Join Date: Nov 2003
Location: Springfield, MO
Posts: 1,601
Send a message via AIM to baldingwxguy
Default Lapse rate question

I'm a bit rusty...I think I know the answer to this (polar region) but I'm not sure how to do a good job explaining it scientifically. This came from a viewer who's taking classes in meteorology.

"Where would you expect the moist adiabatic rate to be greater: in the tropics or near the North Pole? Explain why.
When I read the material I get confused and kinda talk myself in circles...Cold air doesn't have as much and can't hold as much water vapor as warm air, so it can't release much latent heat. The more water vapor in the air, the more latent heat can be released when condensation takes place, and any warming by latent heat partially offsets the cooling of rising air... Condensation occurs mostly at higher temp. So this leads me to believe it would be greater over the tropics, but when you consider the fact the air is saturated at the North Pole, you lean the other way. Please help!!!"
__________________
In the Ozarks, we get rain, snow, and everything in between. We also call it liquid death, white death, etc.
baldingwxguy is offline   Reply With Quote
Old Jun 29th 2009, 09:43 AM   #2
TAFKA wacowx
King of all Meteo
 
TAFKA wacowx's Avatar
 
Join Date: Jan 2003
Location: Houston, TX
Posts: 10,428
Send a message via AIM to TAFKA wacowx
Default

HINT: Check the slope of the adiabats on a Skew-T diagram.
__________________
Everybody's got something to hide 'cept for me and my monkey!
TAFKA wacowx is offline   Reply With Quote
Old Jun 29th 2009, 09:46 AM   #3
wx or not
A Bit Off Center
 
wx or not's Avatar
 
Join Date: Oct 2007
Location: North of Cincinnati
Posts: 14,569
Default

It's the tropics. The adiabatic region is defined as where convection controls the vertical distribution of temperature. Steeper temperature lapse rates would result in greater updraft buoyancy.

edit: Consider tornadogenesis and the impact that greater lapse rates would have.
__________________
Enjoy the veal! Be sure to tip your weatherman!

Last edited by wx or not; Jun 29th 2009 at 10:02 AM.
wx or not is offline   Reply With Quote
Old Jun 29th 2009, 09:48 AM   #4
TAFKA wacowx
King of all Meteo
 
TAFKA wacowx's Avatar
 
Join Date: Jan 2003
Location: Houston, TX
Posts: 10,428
Send a message via AIM to TAFKA wacowx
Default

Poles:

As for the why/explain: There is much less water vapor at the lower temperatures of the poles, therefore, the air will cool much more quickly than saturated air in the tropics.

More water vapor=more condensation with increase in height=increased latent heat production=less of a temperature drop

MA lapse rate in colder climes is much larger meaning many more degrees lost per quivalent increase in height from a saturated parcel of air.
__________________
Everybody's got something to hide 'cept for me and my monkey!
TAFKA wacowx is offline   Reply With Quote
Old Jun 29th 2009, 10:15 AM   #5
ill tempered kelp monkey
Senior Member
 
ill tempered kelp monkey's Avatar
 
Join Date: Sep 2006
Location: Los Angeles
Posts: 649
Default

Balding,

where were you when I was actually in school? you could've been worth about 1.0+ on the ole gpa.
ill tempered kelp monkey is offline   Reply With Quote
Old Jun 29th 2009, 10:38 AM   #6
wx or not
A Bit Off Center
 
wx or not's Avatar
 
Join Date: Oct 2007
Location: North of Cincinnati
Posts: 14,569
Default

waco, thank you. I agree with you. When I went to class, we threw sticks in the air. If they came down wet, we knew convection could be at play.
__________________
Enjoy the veal! Be sure to tip your weatherman!
wx or not is offline   Reply With Quote
Old Jun 29th 2009, 10:48 AM   #7
MOCR
Open Line Veteran
 
MOCR's Avatar
 
Join Date: Jun 2003
Location: TEXAS
Posts: 2,745
Default

You had sticks?? Man, we didn't even have AIR when I was in school. We learned lapse rates of cooling lava back then...

__________________
"There are storms that are named, storms that are not named, and storms that are named that are not storms" -NHC Director Rumsfeld
MOCR is offline   Reply With Quote
Old Jun 29th 2009, 11:02 AM   #8
wx or not
A Bit Off Center
 
wx or not's Avatar
 
Join Date: Oct 2007
Location: North of Cincinnati
Posts: 14,569
Default

You had a SCHOOL? I would've killed for one of those. Our classes were held in trees, and we swung down every day just to pick up our learning materials...
__________________
Enjoy the veal! Be sure to tip your weatherman!
wx or not is offline   Reply With Quote
Old Jun 29th 2009, 01:58 PM   #9
News Is Broken
Left of my own accord.
 
News Is Broken's Avatar
 
Join Date: Sep 2005
Location: No longer here. This forum has been overrun by trolls and I'm done.
Posts: 15,972
Default

Quote:
Originally Posted by wx or not View Post
You had a SCHOOL? I would've killed for one of those. Our classes were held in trees, and we swung down every day just to pick up our learning materials...
Wait... you had TREES?
__________________
-News is Broken

All mouth and no stones New York'rr chickens out of a simple bet.

"Mr. Broken is being a bad boy." - Traffic Goddess
News Is Broken is offline   Reply With Quote
Old Jun 29th 2009, 05:05 PM   #10
Stormtracker_Tony
Open Line Elite
 
Stormtracker_Tony's Avatar
 
Join Date: May 2005
Location: checkoslovocia
Posts: 7,491
Send a message via AIM to Stormtracker_Tony
Default

Quote:
Originally Posted by TAFKA wacowx View Post
HINT: Check the slope of the adiabats on a Skew-T diagram.
This was my first thought...By looking at the Skew-T, you'll notice the moist adiabats (redish/brownish lines) are much steeper at colder temps...

Stormtracker_Tony is offline   Reply With Quote
Old Jun 30th 2009, 01:12 AM   #11
itelltheweather
Senior Member
 
itelltheweather's Avatar
 
Join Date: Dec 2005
Location: Deep South
Posts: 250
Default

Quote:
Originally Posted by baldingwxguy View Post
I'm a bit rusty...I think I know the answer to this (polar region) but I'm not sure how to do a good job explaining it scientifically. This came from a viewer who's taking classes in meteorology.

"Where would you expect the moist adiabatic rate to be greater: in the tropics or near the North Pole? Explain why.
When I read the material I get confused and kinda talk myself in circles...Cold air doesn't have as much and can't hold as much water vapor as warm air, so it can't release much latent heat. The more water vapor in the air, the more latent heat can be released when condensation takes place, and any warming by latent heat partially offsets the cooling of rising air... Condensation occurs mostly at higher temp. So this leads me to believe it would be greater over the tropics, but when you consider the fact the air is saturated at the North Pole, you lean the other way. Please help!!!"
My Reply: DO YOUR OWN HOMEWORK!
itelltheweather is offline   Reply With Quote
Old Jun 30th 2009, 02:09 AM   #12
Stormtracker_Tony
Open Line Elite
 
Stormtracker_Tony's Avatar
 
Join Date: May 2005
Location: checkoslovocia
Posts: 7,491
Send a message via AIM to Stormtracker_Tony
Default

Quote:
Originally Posted by itelltheweather View Post
My Reply: DO YOUR OWN HOMEWORK!
Reminds me of the time I got a basic weather question from a viewer email that was worded in a textbook form...My response was:

Hi XXX, Sounds like a nice school project you've got there. My advice would be to go to your school library and check out some books that are related to this topic. If you don't have any luck with that, there are also places called the "public library" that you probably have somewhere near your area. These are like school libraries, but much bigger and have more books that your school probably doesn't have. You will almost certainly find what you're needing there. If there's anything in those books that you don't understand, feel free to email me back with what it says and I'll try to explain what it's saying a little better. Have a great day!
Stormtracker_Tony is offline   Reply With Quote
Old Jun 30th 2009, 03:41 AM   #13
TAFKA wacowx
King of all Meteo
 
TAFKA wacowx's Avatar
 
Join Date: Jan 2003
Location: Houston, TX
Posts: 10,428
Send a message via AIM to TAFKA wacowx
Default

Quote:
Originally Posted by Stormtracker_Tony View Post
This was my first thought...By looking at the Skew-T, you'll notice the moist adiabats (redish/brownish lines) are much steeper at colder temps...
What do you mean by 'steeper'?

The brown lines to the left have a much more gentle slope (let's say around 45 degrees) as compared to the ones at higher temps (80-90 degrees)
If they were hills, which would you rather climb? Which is steeper?

In my definition of steep, the warmer readings win...their slope is much steeper.

Either way, the temperature drops more, i.e. the lapse rate is greater, along the moist adiabat in colder climes.
__________________
Everybody's got something to hide 'cept for me and my monkey!
TAFKA wacowx is offline   Reply With Quote
Old Jun 30th 2009, 04:16 AM   #14
itelltheweather
Senior Member
 
itelltheweather's Avatar
 
Join Date: Dec 2005
Location: Deep South
Posts: 250
Default

Quote:
Originally Posted by Stormtracker_Tony View Post
Reminds me of the time I got a basic weather question from a viewer email that was worded in a textbook form...My response was:

Hi XXX, Sounds like a nice school project you've got there. My advice would be to go to your school library and check out some books that are related to this topic. If you don't have any luck with that, there are also places called the "public library" that you probably have somewhere near your area. These are like school libraries, but much bigger and have more books that your school probably doesn't have. You will almost certainly find what you're needing there. If there's anything in those books that you don't understand, feel free to email me back with what it says and I'll try to explain what it's saying a little better. Have a great day!
In my last market, in late April for three years running I would get dozens of emails asking for the month's climate data. The requests would come mostly from parents and a few bold students. I would make sure I got their names and passed them along to the science teachers at the elementary school doing the project. I guess the parents never thought of it as cheating. I bet they were shocked when their kid didn't get an A on an easy project.
itelltheweather is offline   Reply With Quote
Old Jun 30th 2009, 08:28 AM   #15
Stormtracker_Tony
Open Line Elite
 
Stormtracker_Tony's Avatar
 
Join Date: May 2005
Location: checkoslovocia
Posts: 7,491
Send a message via AIM to Stormtracker_Tony
Default

Quote:
Originally Posted by TAFKA wacowx View Post
What do you mean by 'steeper'?

The brown lines to the left have a much more gentle slope (let's say around 45 degrees) as compared to the ones at higher temps (80-90 degrees)
If they were hills, which would you rather climb? Which is steeper?

In my definition of steep, the warmer readings win...their slope is much steeper.

Either way, the temperature drops more, i.e. the lapse rate is greater, along the moist adiabat in colder climes.
I get what you're saying...By steeper, I was referring to the phrase "Steeper lapse rates"...As in, a drop in temp of 7 degrees/kilometer is steeper than a drop of 5 degrees/kilometer...The slope is actually "flatter" on the graph at colder temps, but it's "steeper lapse rates" by definition as the temperatures fall at a greater rate with height.
Stormtracker_Tony is offline   Reply With Quote
Old Jul 1st 2009, 04:14 AM   #16
baldingwxguy
Open Line Veteran
 
baldingwxguy's Avatar
 
Join Date: Nov 2003
Location: Springfield, MO
Posts: 1,601
Send a message via AIM to baldingwxguy
Default

Quote:
Originally Posted by TAFKA wacowx View Post
Poles:

As for the why/explain: There is much less water vapor at the lower temperatures of the poles, therefore, the air will cool much more quickly than saturated air in the tropics.

More water vapor=more condensation with increase in height=increased latent heat production=less of a temperature drop

MA lapse rate in colder climes is much larger meaning many more degrees lost per quivalent increase in height from a saturated parcel of air.

Thanks waco...this is essentially what I was thinking.
__________________
In the Ozarks, we get rain, snow, and everything in between. We also call it liquid death, white death, etc.
baldingwxguy is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Sweet Time Lapse MoistureFluxCapacitor WX Line 14 Jun 30th 2012 05:56 PM
Jobless rate in Western US tops 10 percent tater Open Line 45 Jun 23rd 2009 01:39 PM
False Alarm Rate SevereClear WX Line 71 May 21st 2009 05:31 AM
I Caught a Microburst on my Time Lapse! MoistureFluxCapacitor WX Line 4 May 8th 2008 02:52 PM
Can you all help increase thier response rate? MI_Wxman WX Line 4 Mar 4th 2008 09:34 AM


All times are GMT -8. The time now is 05:18 PM.
Skin design and concept by DigitalVB.com