Announcement

Collapse
No announcement yet.

Lapse rate question

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • 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.

  • #2
    HINT: Check the slope of the adiabats on a Skew-T diagram.
    Everybody's got something to hide 'cept for me and my monkey!

    Comment


    • #3
      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.
      Last edited by wx or not; Jun 29th 2009, 11:02 AM.
      Enjoy the veal! Be sure to tip your weatherman!

      Comment


      • #4
        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!

        Comment


        • #5
          Balding,

          where were you when I was actually in school? you could've been worth about 1.0+ on the ole gpa.

          Comment


          • #6
            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!

            Comment


            • #7
              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

              Comment


              • #8
                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!

                Comment


                • #9
                  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

                  Comment


                  • #10
                    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...

                    Comment


                    • #11
                      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!

                      Comment


                      • #12
                        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!

                        Comment


                        • #13
                          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!

                          Comment


                          • #14
                            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.

                            Comment


                            • #15
                              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.

                              Comment

                              Working...
                              X