August 22, 2011
- Good design can be defined different ways, but it almost always means organizing and presenting information in an engaging and/or innovative manner. The Weather Wheel created by Bard Edlund is an outstanding example of this, and I dare you to not stare at it for at least 10 minutes. (Hint: the size of the blue dots changes to represent how much rain the given city recieves, the orange circle’s intensity represents temperature, and the speed at which the arrow passes by the city represents how much wind it gets.) Via Kottke.org
- Cinemagraphs are photographs in which one small part of the image is animated to create continuous motion. This new technique creates surreal and sometimes slightly creepy images the blur the line between video and still photography. The technique is being pioneered by photographers Jamie Beck and Kevin Burg. Fascinating.
It may take many more days before NWS survey teams can finish their assessment of the damage from the April 27th tornado outbreak, but being the weather nerd that I am, I want to go ahead and share a collection of links where you can find preliminary reports on the tracks and intensities of some of the many twisters that touched down. Note that there is at least one EF-5 (the highest intensity with winds over 200 mph) tornado confirmed, and there could be more upgraded to that status as more damaged is inspected. NWS Memphis survey– covering parts of northern Mississippi. NWS Jackson, MS survey. NWS Hunstville, AL survey. NWS Morristown, TN survey. And finally, this graphic from the NWS Birmingham, AL survey. The most complete graphic I’ve seen:
So that’s the bad. Please make a donation to the American Red Cross or any other legitimate organization providing relief for those devastated by this natural disaster. Now for some good things to lighten the mood.
I will call the news of Osama bin Laden’s assassination good, but I certainly will never rejoice the death of any human being. While I am relieved somewhat, and do feel that justice has been done, I’m quite certain that the assassination itself as well as the celebrations will only give the rest of al-Qaeda even more reason to attack the US and its allies.
In even better and much much much lighter news, Moustache May has begun its final year of activity. I participated back in 2008 and am doing so again this year. Due to some very important meetings happening last week at my work, I was unable to start my stache until Friday, so I’m basically starting with a clean slate. Right now I look utterly creepy but hopefully we’ll get past that stage very soon as it fills in.
I came across this absolutely amazing new music video for the Supermen Lovers’ track “Take A Chance” and decided that it was the best thing to end this post with. Enjoy. (Via Too Many Sebastians)
April 29, 2011
So I’m thinking that some Fridays I’m gonna steal NPR’s “Science Friday” idea and write a post debunking some popular myths. Not gonna happen every Friday, but I’m gonna make a pointed effort to do it somewhat often.
Today we’ll tackle the myth about water spinning in opposite directions down the drain in the northern and southern hemispheres. This is simply not true at all. While large-scale weather systems do indeed follow this pattern due to a phenomenon called the Coriolis Effect, water going down a drain does not. Minute things such as imperfections in the angle at which a basin was installed, inconsistencies in the surface or shape of the basin, and any residual motion in the water itself are what determine the direction the water rotates when drained. Once the water begins to drain, the conservation of angular momentum takes over and any hint of rotational motion in the water, whether clockwise or counter-clockwise, gets amplified as it moves toward the drain, creating a vortex. This is the same law of physics that causes tornadoes and dust devils to behave the way they do. The classic explanation for this concept is the spinning ice skater. As he/she moves her limbs closer to their body the conservation of angular momentum forces their rotational speed to increase. They can then move their limbs further away and they will slow down again. So no, no matter what you’ve heard, water does NOT always drain counter-clockwise in the northern hemisphere and clockwise in the southern. That being said, experiments have been done that show the Coriolis Effect can be seen in draining water IF AND ONLY IF all other forces are completely removed. A large and absolutely perfect cylinder-shaped container with one very small hole exactly in the center was filled with water and allowed to sit untouched for 24 hours to allow any residual motion in the water to die out. The container was perfectly balanced with extreme precision. The plug in the hole was then carefully removed and the water did eventually start rotating counter-clockwise, and continued to do so when the experiment was repeated. BUT clearly this only happens in extremely controlled conditions. In your sink or toilet, a myriad of other forces are orders of magnitude stronger and completely overwhelm the minute effect of the Earth’s rotation. Snopes has a decent debunking of this myth as well.
Tornadoes are different. I was asked about this yesterday, in the wake of the massive tornado outbreak on Wednesday. The Coriolis Effect does influence the direction tornadoes spin, but in a more indirect way. There have, in fact, been clockwise (anticyclonic) tornadoes documented in many cases in the U.S. There have even been a few storms that dropped multiple tornadoes, both cyclonic and anticyclonic, at the SAME TIME. As I said earlier, the Coriolis Effect is what causes large-scale weather systems such as hurricanes, low pressure systems, and high pressure systems to rotate the way they do. Low pressure systems and hurricanes always rotate counter-clockwise in the northern hemisphere and clockwise in the southern. The opposite is true for high pressure (clear weather) systems. The storms which produces tornadoes are always associated with a large-scale low pressure system. The Coriolis Effect determines the rotation of that large-scale system, which in turn has an indirect influence on the structure of the supercell thunderstorms which spawn tornadoes. Tornadoes are far, far more common in the U.S. than anywhere else in the world, and because the warm moist air which “feeds” these storms at the surface is moving in from the southeast, and the cooler, drier air aloft is moving in from the northwest, that setup naturally lends itself to counter-clockwise rotation, hence most but not all tornadoes in the U.S. spin counter-clockwise. This illustration from NOAA’s National Severe Storms Laboratory shows the inner workings of a tornadic storm quite well:
The U.S. Department of Energy’s Office of Science Education has a website called NEWTON, with a forum of sorts called “ask a scientist.” This very question regarding the rotation of tornadoes was asked, and I found this particular response quite helpful:
At least the great majority of tornadoes rotate counterclockwise (as do all low-pressure systems) in the northern hemisphere, and clockwise in the southern hemisphere, for the reason (coriolis force) given by Eric Peterson in response #1. But occasionally, it would seem, northern hemisphere tornadoes do rotate clockwise: S. Flora’s book “Tornadoes of the United States” cites an 1890 article in the American Meteorological Journal. Its author, a J.P. Finley, states that, of 550 American tornadoes he studied, 29 were deemed to have rotated clockwise. I have not been able to find any “modern” study of this question. But I believe it could be true. The region of swirling air that contracts to become the tornado is not itself large enough in extent to have its rotation dictated by the coriolis force; rather, it “inherits” this tendency from the great masses of air whose movement sets the stage for the storms and any associated tornadoes. If the study cited is correct and representative, on occasion the direction of rotation is set by some other factor, perhaps the topography in the area where the tornado forms, for example.
So there you have it. I won’t have as much time every week to write up a post this in-depth, so don’t expect this every Friday, but I’ll do my best.
February 9, 2011
Thundersnow is possibly the coolest-sounding meteorological term I can think of. It happens very rarely, but when it does it’s awesome. Convection strong enough to cause lighting during a snowstorm is simply amazing, as are most things that rare. Through a ridiculous stroke of luck, scientists in Huntsville, AL got a rare opportunity to study this bizarre phenomenon in-depth. As you may know, Huntsville is home to NASA’s Marshall Space Flight Center. There are meteorologists and other scientists there with a barrage of better-than-average instruments that monitored the inner-workings of the snowstorm that hit the area Jan. 9th. They got the most thorough data ever recorded for thundersnow, and observed one bolt of lightning that traveled a whopping 50 miles horizontally before hitting the ground. The fact that such a rare and interesting phenomenon happened right on top of a facility so well-equipped to study it is quite remarkable, and those scientists were very excited to be able to study the thundersnow in such great detail. I look forward to seeing what is learned from this experience. (Via Discovery News)
NASA has been presented with yet another viable commercial option for replacing the Space Shuttle’s role of ferrying astronauts to and from the space station, as well as carrying cargo. A U.S. company called Alliant Techsystems teamed up with Europe’s Astrium to draft the proposal for a new rocket called Liberty. This new rocket would combine research of the now-dead Constellation program with the proven components of the European Space Agency’s Ariane 5 launch system. Since this collaborative effort combines mostly well-proven technology, it would be both cheap and relatively quick to build, shortening the problematic gap between the last Space Shuttle flight and the first availability of commercial access to space. If it truly will shorten said gap, I’m all for it. I hope it’s really as good as it sounds, but things like this always run into unforseen problems/delays. Right now, SpaceX still has the edge simply because it’s already had 2 very successful tests of its launch system, the Falcon 9 rocket and Dragon capsule. But Liberty could give SpaceX a run for their money. Check out the promo video below. (Via Universe Today)
February 2, 2011
Some cool science-related stuff I’ve come across the past few days:
- Let’s be frank, the climatologists were absolutely dead wrong in their prediction of a warmer-than-average winter in the eastern US for 2010/2011. Their forecast was based on the fact that historically, La Nina winters are warmer in the eastern US. We are definitely in a La Nina winter, so what the hell has been going on? The fact is, the global climate is VERY complex, and our computer models for both short-term and long-term forecasting are still struggling to get a grasp on what’s really going to happen. The main culprit for our cold winter this year is the Arctic Oscillation. This is another large-scale weather pattern that is fairly unpredictable over the long-term, and has so far overpowered any effects the La Nina pattern has had on the southeast US. The Nashville office of the National Weather Service has been posting fairly frequent updates about this situation, so I recommend reading the latest one to get the detailed explanation you may or may not be desiring. It would appear that winter will be re-establishing its grip on TN for a few more weeks at least.
- In the past year all the major mobile phone service providers have been touting their new 4G networks. But honestly none them have speeds even close to what was traditionally defined as “4G.” The International Telecommunication Union has a set of standards for what speeds can be considered 2G, 3G, 4G, and so on. 4G used to be defined as download speeds of 100 Mbps to 1Gbps. Those kinds of speeds won’t be attained for 4 to 5 years, by most estimates. In December of 2009, the ITU changed the rules on what can be called 4G, which allowed all mobile phone service providers to instantly start labeling their slightly improved wireless broadband speeds as such. Most of these speeds are probably better described as “3.5G” or “3G+” but I honestly don’t care. I just don’t want people to think that the speeds they’ll experience on their mobile browsers is somehow leaps & bounds faster. This information came from an article on Wired that I recommend if you want more detailed info.
- I came across this amazing video clip on Universe Today on Monday, but am just now getting around to posting. The sense of scale when talking in astronomical terms is very difficult for a human mind to comprehend, so when things like this come along that really help illustrate that sense of scale, I’m fascinated. This video clip shows what several different planets, including another earth, would look like in the night sky if they were as close to us as the moon. Just wait until Jupiter shows up. (According to the comment from the creator below the video, this is actually what it would look like through a weak pair of binoculars… so what you’re seeing isn’t meant to depict the entire night sky, only about 62 degrees of it.) Be sure to click on the HD button and make it full screen.
December 22, 2010
I’ve been holding off on blogging about this, but since I’m heading out of town tomorrow, I feel I must mention it today. There’s actually a decent chance of some measurable snowfall on Christmas day this year not only in Nashville, but in most of TN, and even some states south of TN. Here are the official statistics on a white Christmas in Nashville, from the National Weather Service:
THERE HAVE BEEN ONLY NINE CHRISTMASES WITH MEASURABLE AMOUNTS OF SNOW SINCE SNOWFALL RECORD KEEPING BEGAN IN NASHVILLE BACK IN THE WINTER OF 1884 AND 1885. THE LAST TIME MEASURABLE SNOW FELL ON CHRISTMAS DAY IN NASHVILLE WAS IN 1993 WHEN THREE TENTHS OF AN INCH WAS MEASURED. TRACE AMOUNTS OF SNOW FELL ON CHRISTMAS IN 2002. STATISTICALLY THERE IS ONLY A 7 PERCENT CHANCE OF MEASURABLE SNOW ON ANY GIVEN CHRISTMAS. THE MOST SNOW EVER TO FALL ON CHRISTMAS IN NASHVILLE IS 2.7 INCHES IN 1969.
The storm system that has been contributing to the unusual rainfall in southern California will be sliding across the southwestern states today and tomorrow, and joining with an upper level disturbance from the north. The upper level disturbance will be providing the cold, while the low pressure system to the south will be providing the moisture. As the two combine, moisture will be spread north of the low pressure system over the gulf coast on southerly winds, which will bring enough warm air to change the precip to rain on Christmas eve day, but that night the cold air from the upper disturbance will take over and switch it back to snow, which should continue into at least Christmas morning. From what I’ve read, the models are in fair agreement on the timing of the whole thing, but not on the amount of moisture (read: depth of snow) involved. So we’ll have to wait until probably this time tomorrow, or even tomorrow night to really get a good grip on snow amounts. Even then, models can only go so far. I wouldn’t get my hopes up for any “deep” snow though, I’d be very surprised if Nashville got more than 2 inches. I will be with my family in northeast TN, so this will all happen about 6 hours later than Nashville, but naturally there will probably be a little more snow there, and I have every intention of taking a trip to the mountains where there’ll be a lot more snow. Maybe even go skiing.
I may find something to blog about over the weekend, but this will probably be my last post until next week. So Happy Holidays!
December 20, 2010
You must’ve heard about this by now, but I’ll mention it to make sure you know: there’s a full lunar eclipse happening tonight, and it just so happens that it’s also the winter solstice, a.k.a. the shortest day/longest night of the year. Just a coincidence, but a relatively rare one. Lunar eclipses aren’t super-rare- we get one about once every 2-3 years, but they can be pretty spectacular if the earth’s atmospheric conditions cast an eerie orange-red hue on the moon. There’s no way to know if that will happen for sure, but from my experience it happens more often than not. Unfortunately there’s a very good chance it will cloudy and/or raining tonight in middle TN, but if you’re elsewhere, good luck! It starts at about 1:30am EST, that’s 12:30am central, 11:30pm mountain, and 10:30pm pacific. For more details and a good rundown of what to expect, visit Bad Astronomy, and for a good explanation of the red/orange hue, visit this NASA article.
And I can’t help but post this comic from xkcd: I agree 100%