Jump to content






Directional Wind Shear


flynhgh31

Directional wind shear, or the change in wind direction with height, plays an important role in weather and affects everything from the sport of ballooning to storm behavior. A change in wind direction with height that is clockwise as viewed from the surface generally means warm air is moving in. Conversely, winds that change counter-clockwise with height means cooler air is headed your way.

In ballooning, directional shear (commonly referred to as “steerage”) is generally most evident in the morning when lower layers of the atmosphere are not well mixed. However, with the help of solar heating from the sun, turbulent mixing causes the stratification of the various wind layers to mix into one layer. This layer, which contains similar characteristics, grows throughout the day until the late afternoon hours when the atmosphere begins to decouple from the surface. Research has shown that the depth of this layer is dependant on the square root of heat transport from the surface to the atmosphere. Some other important parameters include the square root of both the length of daytime heating and the initial amount of stratification.

Directional wind shear also plays an important role in storms. If moderate to strong directional wind shear exists in the atmosphere, storms can begin to rotate much easier, increasing the threat for severe weather, especially tornadoes. One of the first ingredients in tornado formation is a rotating updraft, and a change in wind direction helps the thunderstorm updraft rotate. In fact, fairly recent research has shown that directional shear in the lowest kilometer of the atmosphere is a very important factor in tornado formation. If directional wind shear is too weak, then the storm may not be able to rotate efficiently enough to produce a tornado.

Directional wind shear can be observed using various instruments. One of the simplest is a pibal, which is nothing more than a helium balloon that is tracked by sight through the lower levels of the atmosphere. This type of observation is commonly made in Africa. Here in the US, we use something called a rawindsonde to try and get an understanding of the atmosphere at a given point. Rawindsondes, which are instrument packs carried aloft by a hydrogen filled balloon, are generally launched twice a day and take a large sample of data through the atmosphere. These instruments record temperature, dew point, wind direction and speed as they ascend through the atmosphere. As the instrument rises through the atmosphere, the atmospheric pressure becomes less and less and the balloon expands till it bursts. The instruments then fall back to the earth under the guidance of a parachute. These measurements are then used to determine aspects about the atmosphere related to temperature, moisture and stability. Because of the expense involved in launching this type of instruments, they are only launched on a regular basis in 92 locations across the United States. A few locations where these are launched on a regular basis in the Midwest include Green Bay, Omaha, Davenport, and Minneapolis. Once the data is gathered for a particular site, it is input into the forecast models and is plotted on a chart called a skew T log P. These charts can be found on the internet daily at

 

http://www.rap.ucar.edu/weather/upper .

On the same web page, there is also data that is taken in hourly intervals by wind profilers. Wind profilers are a form of radar that take measurements solely in the vertical. Instead of focusing on precipitation as radar does, wind profilers focus strictly on wind. Wind profilers are prone to errors due to migrating birds. Another drawback to profilers is that they don’t sample the winds below one-half of a kilometer above the ground level.

As you can see, the change of wind direction with height can be observed in many different ways. In the next article, we will discuss land sea breezes and how this affects the sport of ballooning.


User Feedback

Recommended Comments

There are no comments to display.



Join the conversation

You are posting as a guest. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Add a comment...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Balloon News

  • Blogs

    1. This is a very sad blog.

      As many of you know I suffered a massive stroke at the end of February 2020.  I spend most of march in the hospital starting off with 6 days in a coma.  I have now come out of the hospital Weak, Dizzy, Light Headed and unable to fly.   I am now on medication for high blood sugar. (Diabetes). I am on Medication for nerve pain,  I am on medication for High Blood pressure and a few others that I am unaware what they do but my wife puts them in my pill box and I take them.  I am on the phone (Virtual visit) with my doctor about every other week.  Only 1 in 4 survive the stroke I had and about 60% of those who do survive have permanent disabilities.  I do realize how incredibly fortunate I am just to be here. My family (including the balloon world) has been an inspiration to me and kept my drive to continue alive.  In reality, I have managed to come thru reasonably unscathed.  I still have (after being home two months) issues with my strength and equilibrium.  I get very dizzy or lightheaded (I feel like I am on a boat in the ocean) but my mental acuities and physical aptitude are unencumbered.  I have managed to loose enough weight that my medication for High Blood pressure has been reduced once already.  I continue to work each day on the internet, projects in the shop and other house hold chores to keep me busy and build my strength. 

      tissue2.jpgI am slowly coming to grip with the realization that I will never fly commercially again.  After nearly 7,000 flights and who knows how many tens of thousands of passengers I will never again be able to share my joy with those who have never experienced the amazing bliss of a Hot Air Balloon flight. 

      I started my balloon adventure at the age of 13 when my parents took me to see the National Balloon Championships in Indianola Iowa.  I went home and began to build model hot air balloons out of tissue paper and cellophane tape.  At tissue3.jpgfirst they were very crude and I burned up a few before I perfected my aircraft.  Eventually I created a tissue paper balloon with its own burner fed by 50 feet of plastic hose.  The burner was made out of a syringe from a hospital and tin foil.  My "Burner" was clipped in the mouth of the balloon where I would turn the fire, up and down, from the ground with a propane regulator stolen from my fathers Coleman camp stove.  One of my favorite tissue paper balloons was the balloon (on the right) I built for my high school.  It was Blue and White (School colors) and about 9 feet tall.  In the photo I am demonstrating it for my old Jr. High school in the Gym.  Try doing that now a days. I would fly that balloon in the end zone at school football games.  I would continue to fly that balloon even after I had my pilots certificate and my own real hot air balloon. 

      I started my training to become a Hot Air Balloon Pilot in the fall of 1975.  At that time I was 15 years old.  I completed my training and solo flew a balloon while I was 16 years old.  At 17 years old ( With my parents help) I was able to purchase the balloon I had trained in 549484_10151575146373424_1255794086_n.jpgand began my ballooning adventures.  I finished in the top 10 in the Iowa State Championships in 1977.  That same year I flew as a non-comp pilot in the National Balloon Championships in Indianola Iowa.  The same place, where just a few short years before I was a wide eyed 13 year old watching over a snow fence at balloons launching and floating directly over my head from the Simpson Collage campus.  Over the years I have had the privilege to meet and fly with many of the balloon world's "Hall of Famers".  I was able to fly with, (what today are considered) the legends of the sport.  As Capt Phogg would say, "I learned to fly balloons back in the day's when ballooning was dangerous and sex was safe"  (1)

      I am sadly coming to the horrible realization that my commercial flying days are over.  Even now as I recover I am starting to realize that in my condition just flying a balloon could be dangerous for me even if I were alone.   If you are reading this and have been one of 3rdplace.jpgmy past passengers you will undoubtedly realize the passion I had for balloon flying and the love I had for the intricacy of flight and how to "ride the wind". There is simply nothing in life I loved better than the artistry of flying a balloon.  It did not matter to me if I were flying passengers or training students or even flying competition I loved to fly.  I also loved passing along the knowledge of the art form.  I have an old testimonial page from our original Jeff78Natioinals.jpgwebsite years ago that has HUNDREDS of guest book entries. If you read them you will notice that most of them talk about my passion for flying. As one of my passengers said, "Your passion is hard to hide and very infectious".  Even my own father would comment on how I would amaze him with my desire to fly, even after all of these years.  So the idea that I can no longer fly is more than heartbreaking.  At this time there are things I still want to do in Ballooning.  I want to win the National Classic!  I want to take my son for his first flight!  I want to finish training my last two students!  I want to fly more passengers and share the AWE, that is balloon flight! There is so much more I want to do but I simply can not.  There is too much risk for me and for anyone I take along.

      Never told anyone this before.  I was at the National Balloon Championships in Battle Creek Michigan with my father.  We were on the last day of competition and the flight weather was marginal at best.  I had borrowed a balloon from Dave Sullivan (2).  It was a 90K balloon and we were sent out on a GO for flight.  My father made the decision that he would not fly because of the wind.  The conditions were well beyond what we would take passengers flying in, but, this is the National Championships and we are flying with the best of the best.  I was in go mode until my father came up to me and said " I am not going to fly but I will ride with you if you want.  In these conditions you will need the weight".  The balloon, I had borrowed was large enough to carry a pilot and three adults.  In windy conditions and without the proper weight load you are more or less flying a garbage bag in a hurricane.  The winds will toss you around like a rag doll since you do not have the proper load onboard.  So technically my father was correct.  I would need the extra weight on board to help with the performance of the balloon.  BUT....  Father was well into his 70's at this point.  There was a good chance that w35789_401582233423_3999749_n.jpge would be beaten up good on landing, even a good landing at those speeds.  When you land a balloon, you land at what ever the speed of the wind is.  In a balloon that is under loaded you will never get the balloon stopped.  You simply do not have the weight to stop the balloon as the fabric catches the wind and acts like a sail.  I told my father "I am going to stay on the ground too".  I simply could not take the chance of hurting my father at that age.  A broken bone in your seventies may not heal for years.  I wanted to fly in the competition but did not want to do it at the risk of my fathers health.  I shed several tears on the way back.  I hope some day to become half the man my father is.

      I am now going thru decades of balloon equipment trying to evaluate what is trash and what could be worth something to someone.  I have so much stuff.  Radios, Tanks, GPS, Go-Pro cameras, compass's, Baskets, Fans, Vans, Trailers and more.  Trying to sort thru all the stuff is a daunting task.  Slowly we are listing the items here on this site.  Hopefully the items will find a new loving home and continue the task of creating amazing memories for those who fly.

      EYMasterPilottn.jpgAt this point all I can do is reminisce about the past 45+ years and the wonderful people I have met and the amazing things I have been able to do while involved in ballooning.  I may need to sit down and tell a few stories over the next few years.  Many fun stories and some scary ones as well.  Most of all I need YOU!  I need you to continue to use the HotAirBalloonist.com site.  Become a member and help me spread the wisdom, knowledge, advice and more to the next generation of balloonists.  I no longer have the ability to earn my living from balloon flying.  It is my hope that I can earn a living with my abilities on the web and mostly this site.  Please tell your friends about this site.  Go get a membership right now and start a club.  Ask me if you need something built.  TonyT.jpgWhat features do you want to see on the site?  I have been involved in every aspect of the balloon world.  From repairs to competition and Cold Air balloons to entire envelope rebuilds.  I have flown in many locations and built 100's of inflatables.  I have built custom inflatables, from standard style inflatables to Lemon aid cups to propane tanks to Tony the Tiger head to an airbag on a billboard and even a 68ft tall Christmas tree.  I have a ton of knowledge and experience and I feel a strong desire to pass this along to as many as care to listen.  This website is my vehicle and you are the driver.  Without paid members I can not continue to support this site. 

      Thank you to everyone whom have touched me and my family.  The balloon world is such a fascinating and fantastic place to be a part of.

      Jeff A Thompson

       

      (1) Thank you Capt. Phogg for your quip's that I still use.  AKA Dennis PHloden  He will understand.

      (2) Dave Sullivan is a dear friend and mentor.   I was privileged to fly with him in the Harley Davidson Balloon at the National polegrab.jpgBalloon Classic in the Key Grab event.  Dave actually got the ring off the top of the pole in front of more than 10,000 screaming fans!

      Desktop.jpg

      13912707_10209416229550211_7125047307562247566_n.jpgAlbqJerry.jpgAlbqParade77.jpg601956_10151575145868424_1720804527_n.jpg13900341_10209362276681423_3503529173547196436_n (1).jpg

      58060_471234993423_6505325_n.jpgclassicpng.jpg

      CaptKiddsm.jpg

      • 1
        entry
      • 0
        comments
      • 2694
        views

      Recent Entries

      Looking to find a way to have this file available, coverted, or just taught how to convert this inormation t a .rmap file. It seems that with two nav it is the only option for the Android system.
      Does someone actually have the coordinates to all the indianola targets also for GPS input.

      • 1
        entry
      • 1
        comment
      • 3299
        views

      Recent Entries

      Kevin Cloney
      Latest Entry

      We recently competed our first safety seminar in Las Vegas. We received great input and are looking at our second seminar tentatively scheduled in Sept. Please let us know if you are interested or want further information


    2. Time for the fact of the week!
      The military world was forever changed when 300 years of island security was over with the silent flight of German Zeppelins across the English Channel during World War I. The Zeppelins were gunned down by inexperienced pilots flying untried aircraft. The Zeppelins dropped bombs over the English Island, introducing an alarming new element to the first world war.
      Learn more in the book "The Zeppelin Fighters" by Arch Whitehouse, available to read in the Balloon Museum Library!

    3. We leave in the morning! Packing for two weeks, cleaning the truck, Oil Change, Tire Rotation, Balance, 3400 boxes for the apartment. Pots, Pans, Paper towels, toilet paper, garbage can and bags.. We also bring the big Tent/Awning we use at Jules, Card Printer, GoPro cameras, Logos and vinyl for Tyler’s Trailer, Luggage, Radio’s, Helium Tank, Balloons, Compass, Download the Competition map… Lawn mowed, Dogs to the vet for Boarding, OMG OMG we have been at this for two weeks getting ready and tomorrow we leave.

       

      4 am we hit the road! We will be at Jules house on Thursday afternoon. When we get to Jules we have to set up the Awning. Then put the war paint on Tyler's trailer. Logos and balloons.
      blogentry-1-0-38851500-1437507535_thumb.jpg
      I also have an Inflation Fan for Tyler, It is buried under all sorts of stuff.

       

      blogentry-1-0-06695700-1437507707_thumb.jpg

       

      Jeff

      Sm DSC03248



×
×
  • Create New...