Davis
Instruments Weather Club
May 2006
In This Issue:
WEATHER STATIONS IN ACTION :
Artist Welsby Uses Wind, Trees, and Weather Wizards to Create New Masterpiece
In the world of art, Mother Nature rules. We’ve all been moved by her displays of light, color, movement, and life. Weather nuts proud to bear the name see that kind of artistic beauty every day in the sky and wind and clouds. Now a contemporary artist, Chris Welsby, is using Davis weather stations to present a unique visual image constantly re-designed by the wind.
Chris Welsby’s story was sent to us by Kim Lear, Production Manager for Dream on Film. She wrote that Chris “is an established artist whose film, video and new media projects have had international success for 30 years. His work is very unique in that he produces landscape films, videos and installations that are in some way shaped by the environment. In the past he has made wind-powered cameras, converted an equatorial stand [a device used by astronomers to track the sky as it seems to rotate around the earth’s axis] into a tripod to film the rotation of the planet, and now he has built a wind-powered video edit suite.
“Recently, he used a Davis weather station to monitor the wind conditions outside an art gallery in Toronto, translated the data via customized software and a Mac G5, then projected video images of a tree inside the gallery. The video images speed up and slow down in relation to wind speed and the angles shift in relation to wind direction.
“Why a tree? The shape of a tree is determined by the light and wind. The shape of this projected video is too.”
Chris’s current project in Canada is just the beginning. His newest project is an expanded version of the piece for the South Korean Biennale in Gwanju, an international visual art exhibition and a major event in the Asian art world.
“For the new project, Chris will be setting up weather stations in North America, Europe and Asia to send data to a multi-projection system he is designing with professional programmer Mark Brady,” Kim wrote. “Chris is also a Professor with Simon Fraser University in Vancouver, Canada. He has established partnerships with two other universities in London to host and monitor the stations. He will be using six Davis Weather Wizards to send weather data from Canada and the United Kingdom to the new project in Korea this September.”
Chris also likes the idea of collaborating with other weather watchers. He would love to find a Davis weather station operating in Vancouver or England which could provide very fast updates of wind data to provide a continuous live feed to the system in Korea. If you think you might be able to help, send an email to Chris at welsby@sfu.ca
Weather Check Quiz Question 1: What is the jet stream? How does it “make time fly” – aeronautically speaking? (Click here for answers.)
Have You Checked the Weather World ‘Round Lately?
The Weather World ‘Round page seems to be growing by leaps and bounds and new Vantage Pro2 owners get their data online. You can visit just about any corner of the world with a few mouse clicks! If you are looking for weather-watcher-friendly vacation spot, how about Surrey Lake Fishing Resort in British Colombia, Canada, or the Chamonix Valley in the French Alps, or The Resort at the Mountains near Mt. Hood in Oregon?
Two of our favorite new WWR-ers, Craig and Anita Snively like nice weather. That might be part of the reason they moved south, all the way from the US to Gramado, Brazil, to run a beautiful little inn. Craig said we are all welcome at his pousada, the Colina de Pedra. If the weather and the lovely place aren’t enough temptation, Craig tells us there are 17 chocolate factories in Gramado! We can be packed and ready in 30 minutes.
Weatherman Jimmy Knows His Stuff
Tucson weatherman Jimmy Stewart, who reports on KVOA Channel 4, offers an “Ask Jimmy” column. And we think he is one smart weatherman! Look how he answered a viewer’s question about what kind of home weather station to buy….
WEATHER 101:
Who Needs a Rainbow When You’ve Got Pretty Clouds?
Patrick Ward snapped this photo of glowing clouds over the desert in El Centro, California.
One sunny July day, Patrick Ward and his girlfriend, Maria, were tooling down the highway near El Centro, California, on their motorcycle when they stopped for a water break. (It was 105ºF – El Centro is desert country.) They noticed this “funny rainbow in the clouds overhead.”
“The sky was clear except for these few clouds. How can you get this effect on such a hot day in nearly cloudless skies? The clouds weren't quite as big as they appear (due to a small amount of telephoto effect).”
We asked our resident meteorologist, Jason, for his opinion. “It’s called cloud iridescence,” said Jason.
Cloud iridescence is the result of diffraction of light by the small water droplets within the cloud. Similarly small sized droplets can form coronae, and cloud iridescence is really bits of corona. It usually happens when the clouds are thin and new, which was likely in the case of Patrick’s almost cloudless sky. According to Meteorology Today, “cloud iridescence is most often seen within 20º of the sun, and is often associated with clouds such as cirrocumulus and altocumulus.”
But, as in many weather phenomena, not always. Since it can occur further from the sun, diffraction can’t completely explain cloud iridescence. Current theories involve light reflected from thin plate-like ice crystals, or competing and interfering rays within the clouds layers.
Whatever the physics, it is beautiful! Patrick’s photo is lovely – and there’s another beautiful one on Les Crowley’s very interesting Atmospheric Optics website.
Weather Check Quiz Question 2: Is there a pot of gold at the end of a rainbow? Where did this idea come from? (Click here for answers.)
TECH TIPS:
Free Download of WeatherLink Update
Do you have WeatherLink for Windows? If so, you might want to download the latest update, version 5.7.0, which is now available on our website. Scroll down to “Software Updates.” (Downloaded updates are always free of charge!)
The update includes some changes to the APRS feature (including now sending two minute average wind speed and 10 minute gust to APRS; for Vantage Pro consoles, altimeter setting is reported instead of sea level barometer) and fixes to 5.6.x.
MAILBAG:
WeatherForum.net is Awesome
Gary Oldham (“VP1 owner since 6/2001, VP2 owner since 12/2004, Weather Monitor owner back in 89-92 or so”) enjoyed seeing a mention of the Davis Vantage Pro web ring he manages in the last newsletter. (So that’s who you are, Gary! We couldn’t find a name on the site!)
“Seeing that story,” Gary wrote, “prompted me to think about some other resources I have available for Vantage Pro owners, those considering buying one, and those just plain interested in the weather.”
A few years ago Gary established The WeatherLink Forum . Last summer he established a newer and more general forum, Weatherforum.net with several other discussion areas, including WeatherLink, Vantage Pro, and original Davis stations, which is “growing by leaps and bounds!”
We checked it out and spent quite a few happy, er, moments, wandering around the many interesting topics. We especially liked the “Featured Web Site,” “Agricultural Weather,” “Current U.S. Weather Discussion,” and “Severe Weather” sections. There is so much information on that page, it truly boggles the old boggle-head.
Thanks, Gary!
Up on the Rooftop: Firefighters’ Friend
Captain Gary Cochrun, of the Moorefield Township Fire Department, in Ohio, is jazzed about the station’s new roof-top ornamentation – a Davis Weather Wizard III wireless weather station.
“The unit was donated to us by a local citizen of our community,” Captain Gary wrote. “The receiver is located in our dispatch center. Whenever we are dispatched on a call in which weather conditions may play a factor, we are informed of weather conditions while en route to the call by the dispatcher. This is very helpful to us in emergencies.”
Wireless Weather Wizards have been discontinued by Davis, so the MTFD was even luckier. It could be that the donor upgraded his own system, and found a very good use for his old, but faithfully long-lived, Wizard. If you have upgraded your system, you might want to consider donating the old (we wish there was a better word!) one to your local fire department, school, or police department.
Gary wanted his team’s appreciation to the donor and to Davis known far and wide! Happy to oblige.
Weather Check Quiz Question 3: When we think of the weather’s effect on firefighting strategies, we think of high temperatures and wind. But very cold conditions can be problematic too. Like, the water poured on a burning building freezing and the heavy ice causing the building to collapse. What do you think, did we just make that up, or is it true? (Click here for answers.)
Just Too Cold for that Hut
Terry Galbreath of Calhan, Colorado, was warmed by the story of Gary Ramos sailing around up in the Artic Circle. It brought back some fond, but chilly memories.
“I spent a year at Thule, Greenland, considerably farther north than where Gary is, and the worst day we had was -74ºF (-59ºC) and a 175 mile an hour (282 kmp) wind. A ‘black flag’ day -- no one allowed outside at all. We did lose one of the ‘safety huts’ along the road to ‘work’ (a USAF radar site). Our first clue was when the wind reading for that hut (each hut of 12 was instrumented) went suddenly to zero. We never did find the hut (converted shipping containers cabled down to rock), just the broken cable where it used to be. After a year of that, ANY weather is relative. Right now, I'm enjoying the sunny beaches of Colorado!”
Ahh, nothing like a cool drink under a swaying palm, with the waves crashing there on that beach in Colorado… what beach is that again???
Weather Quiz Question 4: If Terry invents a time travel machine and can go back to when Colorado did have an ocean beach, what date should he program into his machine? (Click here for answers.)
“Cyclone-Rated” Houses Stood up to Larry
Marcello Avolio, of Mareeba, Australia, had a few thoughts about Cyclone Larry, which was mentioned in our last issue. And he’s entitled -- Mareeba is about 100 kilometers from Innisfall, where Larry did the most damage.
“There are a number of reasons why there were no fatalities caused by Larry,” Marcello asserts. “One is that since Cyclone Tracy, all new houses in cyclonic areas must be built to withstand cyclones. Depending where you are and in relation to your surroundings, this could be W41 (41 metres per second) W50 or even W60. [Note: this translates to wind speeds of 92 miles per hour, 112 mph, and 134 mph, or category one, two or three hurricanes.] The most common principal in cyclone-rated houses is that the roof trusses are attached to the footings by steel rods.”
(This is a timely topic here in the United States, where much rebuilding is going on in our hurricane-devastated gulf coast areas. Perhaps we ought to be looking at our friends in Australia for some building guidance?)
Marcello also commented on the fact that anemometers, such as ours, are tested in wind tunnels.
“But in the real world,” he tells us, “the wind is not always clean!! Leaves and twigs fly horizontal at high speeds.”
He wonders if Davis has yet to invent a “high speed” anemometer that can withstand not only the very high wind, but whatever might be carried along with it.
Well, our anemometers are already notoriously sturdy and we have received plenty of letters from users who find them intact and spinning merrily after a huge storm, amid the downed trees and the bits of roof. When the anemometer fails during high winds, it is almost always due, as Marcello pointed out, to flying debris. We’d love to create a unit that would just flex with the impact of a flying twig, cow, or barn side, but for most of our customers that would be more anemometer (and you can bet that means more cost) than they need. It might also mean a tradeoff in size and sensitivity, especially in light breezes. But who knows? Maybe in some future world with no more flat tires, bruised tomatoes, stained trousers, gasoline engines -- oops, guess that version of the future is here. Sigh.
Lighten Up on Alaska
Jim Matti, a proud Alaskan, took us to task for “trying to contribute to the myth that Alaska is dark for six months out of the year” with our quiz question about how long it stays dark in the Arctic Circle (April 2006).
“I can tell you that it does not stay dark ever above the Arctic Circle, at least as far north as Prudhoe Bay where I worked. The correct wording would be ‘How many days does the sun not rise?’ In Pt. Barrow it is about 57 days. In Prudhoe Bay, which is a little further south, it is about 53 days. However, both locations experience daylight during the winter. At Prudhoe Bay on the winter solstice there are about 3 1/2 hours of twilight. I have pictures at solar noon showing a distinctive glow on the southern horizon.”
Fueling mythology is not in our game plan, Jim! We were actually trying to dispel that misunderstanding, and to clarify that the length of "dark time" increases as you move toward the pole from the Arctic Circle. I think most people think that it is the same at say, Prudhoe Bay, as it is right at the pole.
But Jim’s point is a good one: we need to understand that even though the sun does not rise, it may not be “dark.”
“At the pole on solstice perhaps [it stays dark all day], but the further north you are the more twilight you have. I am always amazed when I visit the lower 48 (‘Outside’ as we used to call it) how fast it gets dark after sunset. It seems to be completely dark in about a half hour. Where I live, 60 N, we get one hour or more of twilight – morning and night. The result is the days are not as short as the sunrise/sunset times would indicate. The other side of that is summer solstice, when the sun sets but it doesn’t really get dark. In the summer the sun rises in the northeast and sets in the northwest. In the winter is rises in the southeast and sets in the southwest.
“The winters here at my house are actually milder than a lot of places like Northern Minnesota, but they are a little longer. Right now, we are getting beautiful days and more daylight than you, but with 2-1/2 feet of snow left!”
Jim’s data is online(click on Detailed Weather Information).
Weather Quiz Question 5: Speaking of light in Alaska, we’d love to see the aurora borealis. We’ve been told the best time to go is between late August and early April. But if the Northern Lights are caused by the sun’s magnetic fields, why would the time of year matter?
(Click here for answers.)
His Snowflake Beats Our Snowflake
Philip W. O’Guin could relate to our story about seeing the strange little icon on our Vantage Pro2 console a few weeks ago.
“Shortly after I installed my Vantage Pro on April 19, two years ago,” Philip of balmy Nashville, Tennessee, wrote, “it was kinda chilly outside. I went to my console just to see what the temperature was and noticed that the snowflake was showing. I watched the local weather that night and it said nothing about snow or even the chance of snow. I said to myself ‘this thing is crazy!’ The next morning I woke up to 5" of snow. As I said, it was April 19th -- in Tennessee -- and it was the only snow that winter. I made sure I had plenty of witnesses. Ever since then, I’ve received many calls just to check to see what the weather is going to do.”
Crazy? Like a meteorologist fox!
Weather Quiz Question 5: What kind of a snowflake is our icon?
(Click here for answers.)
YOU'RE BRILLIANT!:
Answers to Quiz Questions
Question
1:
Jet streams are long, wide rivers of fast-flowing air currents, usually up in the tropopause (6 to 9 miles [10 to 15 km] above the earth). The wind speed up there in the middle of a jet stream can be faster than 200 knots, and the path can be looping and meandering. Aeronautically, the jet stream flowing from west to east makes time fly: it takes about an hour less to fly from New York to London than it does to come back! (Source: Meteorology Today, by C. Donald Ahrens) (Back to stories.)
Question
2: First off, honey, no. The fun of rainbows is that you can’t get there from here. Running after an illusion is always a bad idea, and whoever came up with the analogy of the pot of gold was trying to save us all some wasted effort. While nobody knows exactly where the idea came from, most of the lore is rooted in Ireland, where leprechauns are said to have buried their gold so no mortal could get to it. But it probably goes back further than that. According to one legend from Silesia in ancient Eastern Europe, angels put gold under the rainbow for a mortal to find, but with the caveat that only a nude man could obtain the prize. Rainbows have been powerful symbols in almost every culture, and they range from being tools for the gods (pathways, messengers, bows, thrones, hems of divine robes) to tools for departing mortals (soul boat bridges, ladders, gateways to heaven, light shined when the Pearly Gates open) to simple symbols of hope and the “end of the storm.” (Check out this website for lots of info on the many spiritual meaning of rainbows. (Back to stories.)
Question
3: True! We got it from the firefighter’s mouth, said firefighter being Jeffrey Pindelski, Battalion Chief with the Downers Grove Fire Department in Illinois and staff instructor at College of Du Page. His article on cold weather operations can be found on Firehouse.com. (Back to stories)
Question 4: Well, August 2, 256,123,456 BC would be a safe bet. Studies of the limestone and fossils in the Grand Canyon have shown that ancient Colorado was underwater during several different periods, with the top layer of Kaibab Limestone being laid down about 250 million years ago. Anything newer than that has been eroded away, but there was probably an ocean beach in Colorado much more recently, like 65 million years ago, but we hear the beachside cocktail service was much better back in the 250’s. Check out the Grand Canyon Explorer for loads of geologic information. (Back to stories.)
Question 5: The lights are not seasonal. They are active all year round. But seeing them becomes MUCH easier when the sky is darkest. During the long, sunny days of Alaskan summer, you won’t get to see much! For more exact information, the National Oceanic and Atmospheric Administration compiles a map of the aurora’s position. (Back to stories.)
Question 5: According to Kenneth G. Libbrecht’s SnowCrystals website it is a Stellar Dendrite. Didn’t know there were kinds of snowflakes? Mr. Libbrecht’s site has a table of just the 35 most common forms! It’s a very fun site to wander around on – especially when the real thing is NOT piling up on your walkway. (Back to stories.)
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