A HINT OF ADIABATICS – IT’S A GAS!

Friday, 11-21-2008

Several years ago this bag of corn chips was purchased somewhere in Southern California.  Shortly afterwards one of my two former students hiking the Mt. Whitney trail with me pulled it out of his backpack when we were taking a break at the 11,395′ benchmark near Consultation Lake.  Adam and Carl were game hikers and a joy to be with.  I’ve lost track of Adam but Carl (Opper) is an earth science professor at St. Petersburg College.  He makes me proud.

I must admit that right now I have a problem with this image:

IT ACCURATELY DEPICTS

HOW MY ABDOMEN FEELS THIS EVENING!

That strange statement will be explained in a moment.

Of course the reason why the bag is near bursting is because the atmospheric pressure upon it is so much less than it was where it was packaged and sealed.  The image also illustrates that when air rises, it expands.  Interestingly, the “heat” within the air inside the bag is spread out over a greater volume due to the expansion.  Therefore, were it measured, one would find the temperature of the air at any point inside the bag to be colder than it was at the beginning of the hike.  But, the amount of heat inside the bag would be essentially the same as at the beginning of the hike, except for the small amount lost due to radiation cooling of the bag’s surface.

Did you catch that?  When air rises and expands the temperature changes but the amount of heat remains essentially the same.  I was reminded many times during my years of teaching that many people do not discriminate between the word, heat and the word, temperature.  The fact is, they do not mean the same thing.  For example, it takes a lot more heat to increase a gallon of room temperature water up to boiling than to increase a quart of room temperature water up to boiling – though the temperatures of each once the heating was accomplished would be the same at boiling.

When unsaturated air rises, its temperature drops at a rate of about 1degree C. per 100 meters of ascent!  When saturated air rises its temperature drops at a rate of about 0.6 degrees C. per 100 meters.  The reduction (retardation) is due to the fact that when saturated air is rising and being further cooled by expansion – condensation occurs which releases heat; the heat released slows down the rate of expansion cooling.

This is the crux of adiabatic cooling, a subject which will come up sooner or later at this site (as well as adiabatic heating).  NOW: Back to the strange comment about my abdomen.

Even before we returned to our Florida home from our month-long stay at our mountain cabin I knew that something inside my lower abdomen was not quite right.  After getting back to Florida I investigated on-line and correctly reached the conclusion that I had a hernia.  The surgeon found a second one when he examined me.  I had surgery that took a little over two hours early in the afternoon on Monday.  The surgeon found a third hernia while he was in there looking around with his magic wand, the laparoscope.

All went well.  The surgery was done on an out-patient basis.  That’s not a complaint.  Once my head hit the pillow at home I felt very tired but I was not sleepy!  I was so relieved that I jabbered off and on all night long.  My poor wife!  Perhaps the medication played a role in that.

The surgery is the main reason for my inactivity on line – that plus the fact that there is no tropical weather going on right now, being near the end of the official season.  I’ve read that it’s over but my feeling always at this time of year is, “It ain’t over ’til it’s over!” spoken first (I think) by the great living sage, Yogi Berra.  Out-of- season storms have occurred though such events are relatively rare.  Here are two examples:

1) Hurricane Alice formed at 1 A.M. EST December 30, 1954 and continued as a hurricane into January 6, 1955.  Here’s a plot.

http://www.stormpulse.com/hurricane-alice-1954

2) A hurricane formed on March 6, 1908.  It is called both “The March, 1908 Hurricane” and “1908 Hurricane #1.”  Here’s a plot.

http://weather.unisys.com/hurricane/atlantic/1908/1/track.gif

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HURRICANE IKE CIRCULATION – LESSON 1

LEFT CLICK THESE IMAGES TO MAKE THEM LARGER.  YOU CAN ACHIEVE A NICE HIGH RESOLUTION VIEW OF THE IMAGE OF IKE ABOVE WITH A SECOND LEFT CLICK.

Inflow consists of the harder-edged clouds with sharp contrast – Outflow consists of the more diffuse cirrus and cirrostratus of the upper layer.

PLEASE REMEMBER THAT THOUGH THIS IS A TUTORIAL, THE LOCATIONS OF STORMS AS SHOWN ON THE GRAPHICS ARE TIME-SENSITIVE.  TO AVOID MISUNDERSTANDINGS, CONSULT THE DATE AND TIME OF THE POSTING.

With this post you can either simply enjoy the high resolution image of Ike and leave it at that point or explore deeper into the dynamics of storms such as this.

I have provided a large image (above) of Ike completed earlier today followed by smaller images contrasting the circulation below with the circulation above.  Thirdly, you will find below an image of what might seem like a very odd looking hurricane compared to what you have been looking at this season.  To see it, you must ask for more detail when the invitation appears at the end of the next paragraph.

Because of only a small amount of sheer and other factors, Ike is a well-formed system.  And – if you can get past its destructive character you might marvel at its beauty.  I speak of it as though it were a living thing.  In many respects, it is a separate entity with a life of its own.  We even talk about the life cycle of such a storm.  We personify it with a name, in this case a male name.  Its winds spiral because of the Coriolis effect and the whole storm’s path responds to the Coriolis effect – sometimes that is evident, sometimes it is not.  If you find yourself confused about the Coriolis effect, please be patient because I intend to post an item soon, with an explanation of certain aspects of hurricanes which might seem to be contradictions when they are not at all.  Believe me, misunderstandings about the Coriolis effect does cause considerable confusion.

Gustav Generating Conditions Conducive to Tornadoes

The short loop below is from the National Weather Service radar.  The loop ends at 4:38 pm EDT (you can watch the time references on the lower left.  Notice the rain bands that are drawing their moisture up from the SSW (warm, humid air from the Gulf of Mexico).  So, the storm is still being fed by the primary source of energy for all hurricanes, tropical storms, tropical depressions, tropical waves, lines of thunderstorms and individual thunderstorms – the latent heat of condensation.

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Short Radar Loop from NWS

Please visit the rest of this web-log at http://cloudman23.wordpress.com/.  If you are interested in weather, there are some tutorials scattered about and more will be added in time.  At the end of this page there is a cue to click to the previous page or the next page.