It’s such a simple, logical thing to do and yet it’s a mistake made by novice and, oftentimes, experienced travellers: failing to research the weather of your destination city. Everywhere you go, ALWAYS check the weather (sing it, Crowded House!) This is something you should do before you book your flights because nothing puts a (literal) damper on a holiday quite like a monsoon, or days that are so swelteringly hot that you might actually die if you get locked out your air bnb.
Ask the oracle AKA Google: “what’s the best time of year to travel to [insert fabulous destination city]?” or “what’s the climate like?”
Make sure you specify the “city” or region because countries are large and the climate/weather can vary dramatically from north to south and east to west. The June weather in Michigan, for example, may require a sweater; the June weather in Kansas may require a tornado shelter.
Understanding the climate of your destination will help you make smart choices – like not visiting Puerto Rico in hurricane season or Dubai in mid-summer. And you’ll have a much more comfortable stay for it! It also means that you can pack far more appropriately, like not taking thermal underwear on a visit to Vancouver in July. As it turns out, not ALL of Canada is a frozen wasteland all year around.
Do your research and enjoy a safe, comfortable, and happy adventure!
No, this is not a joke, although I’m not referring to the sprites of fairy tales…
A “sprite” is a whimsical name given to a particularly ephemeral upper atmosphere phenomenon that’s generated by lightning discharges in powerful thunderstorm clouds. Sprites are witnessed as whispy colourful flickering shapes above the thunderstorm clouds and in this video, we watch a team of storm-chasers in hot pursuit of these large-scale electrical discharges.
The things people do for science…
Video Source: “Storm Chasing in a Jet – Capturing Upper-atmospheric Lightning” Uploaded by CuriousVideos to YouTube channel www.youtube.com/watch?v=vSCwiQWzMa0.
Original Source: From NOVA – At the Edge of Space by PBS
It took two long haul flights, six plastic wrapped airline meals, three movies, two cantankerous airhostesses and a dangerous brush with halitosis for me to learn about the latest crisis throwing a spanner in the works of the mankind’s (mostly shoddy) attempts to run things smoothly on planet Earth.
I’m talking, of course, about El Niño.
I had to come to Los Angeles to learn that we’re actually teetering on the edge of what the western media is referring to as a “monster El Niño event” and by the time I publish this, we may very well have taken the dive. Where I come from – South Africa – the media and moreover the government pay scant attention to weather and climate issues. This is extremely ironic considering our economy is based on primary industry and that El Niño years are linked with drought in Southern African’s interior. So, in keeping with this relationship, we’re currently facing critical drought conditions for which the government has done nothing to prepare.
Alas! Here in South Africa, the government is far too distracted by President Zuma’s antics in and out of parliament and the country’s courtrooms to worry about the fact that our crops are about to shrivel up faster than Zuma’s manhood when it was explained to him that showering after intercourse does not in fact prevent the transmission of HIV. And unfortunately, they would also rather spend taxpayers’ money on private jets, fancy cars and extravagant lifestyles for its unprecedented number of officials than on research into, and mitigation for climate change and global climate phenomena like El Niño. If you were a selfish, uneducated pack of pricks, wouldn’t you too?
Anyway, that is where my political rant ends. The point is this: I only recently learned that the planet is facing the meanest El Niño event since 1997 and is set to become one of the three strongest on record, like, ever. It’s already causing all kinds of interesting weather anomalies across the world, especially in the United States. So, it’s time for a new blog in which we’ll meet “the boy” wreaking an incredible amount of wanton mischief on our biology, biomes and backyards.
Who Is This “Boy” And Why Does He Mischief Thusly?
El Niño refers to the periodic, unusual warming of the ocean waters of the central and eastern equatorial Pacific and it’s named “the boy” in Spanish after the baby Jesus, since it typically occurs around Christmas time. Understanding why El Niño has such extensive impacts upon weather requires us to take a closer look at a very important variable (sea surface temperature) as it usually is versus what it becomes when El Niño buggers around with ocean and atmospheric circulations. And so, the instigator of it all – the key player I need to introduce you to first is…
The Easterly Trade Winds!
Image Source: mrspruillscience.weebly.com
Over the tropical Pacific Ocean, in other words around the equator, the trade winds blow roughly from east to west (see diagram above). Now, wind may seem like nothing more than moving air until your house gets relocated by a tornado; only then do you realize it’s a force to be reckoned with! So, the effects the northeast and southeast trade winds have on the ocean surface in the equatorial Pacific are quite significant.
The easterlies exert a force on the warm surface water, pushing it and causing it to pile up in the west, so much so that there is actually a 500-milimetre difference in sea surface height between Indonesia (west) and Ecuador (east)! This does a few things:
With the warm surface waters being piled up in the west, an 8°C temperature difference is created between the eastern and western equatorial Pacific, with the west being beautifully toasty. A warm ocean surface makes for a sexy, moist atmosphere and the result is a lot of rainfall. This is why Indonesia is beautifully lush.
On the other side of the Pacific, the wind pushing the surface waters away from the South American coast causes cold water from depth to rise to the surface (upwell), thereby leaving the ocean here chilly enough to embarrass you if you were dude wearing a speedo swimsuit. And, of course, the air overlying a cold ocean is typically dry and promotes little rainfall.
Ocean upwelling is a really important process, so it deserves a little conversation before we continue. When ocean creatures and critters die, their bodies sink, making the waters at depth wonderfully fertile. The upwelling of this water to the surface brings all this organic matter into the glorious sunshine and this leads to a surge in primary productivity. Of course, with great volumes of delicious algae, plankton and other tiny sea squishies available, every critter in the food chain is given the energy influx it needs to prosper, which essentially means lots of rodgering, lots of babies and lots of biological success. It also means lots of sushi for us.
So, we have a warm western equatorial Pacific with a rainy atmosphere and a cool eastern equatorial Pacific and a dry atmosphere. That’s the way it USUALLY is with the northeast and southeast trade winds happily blowing.
However: every two to seven years – and there doesn’t appear to be any strict rhyme or reason as to the frequency of this – the normally healthy trade winds stagger and weaken and you would scarcely BELIEVE the cluster f**k of consequences that follow.
A Specific Account of the Cluster of F**ks That Follow
With the easterly trade winds fizzling out, all the beautifully warm water that is usually swept to the west is allowed to slough back into the east. This causes a tongue of warm water to spread out from the western coastline of North America (see diagrams below).
A key point you must remember is that the ocean and atmosphere seldom, if ever, act independently of each other. One minor change in sea surface temperature can cause the atmosphere to overreact like your girlfriend approximately one week before Aunt Flo arrives for her monthly visit. A warm sea surface leads to greater evaporation, a more humid atmosphere and therefore more rainfall.
So, with ocean heat draining from the usually wet western Pacific, the region is typically left in drought while the east, which is usually dry, becomes unusually wet. On the ground, Indonesia and Australia can experiencing drought and, in Australia’s case, a much greater risk of catastrophic bush fire. On the eastern side of the Pacific, where the ocean has become anomalously warm, unusually heavy rainfall can lead to flooding with the risk being greatest to the southern states of America and Peru.
The weakening of the trade winds also negatively affects the upwelling that usually occurs off the western coast of South America and by throttling the source of nutrients these marine ecosystems rely on, organisms of all echelons in the food chain take a major blow. Less importantly (in the grand scheme of things – don’t tell any local fisherman I’m saying this) our fishing industries also suffer. That’s right: less sushi.
If you thought that’s where it ends, think again. El Niño’s impacts spread further than a desperate housewife’s legs. The accumulation of vast reservoirs of heat energy at the eastern periphery of the equatorial Pacific drive significant changes in global atmospheric circulation, which essentially means that no matter where in the world you live, you can possibly expect the next few months’ of weather to be, uh… interesting.
Crappy Weather Coming To a Neighborhood Near You
Air in the atmosphere is constantly on the move and it’s thanks to our major global atmospheric circulations that all the crap going down in the Pacific is felt in varying degrees across the globe. Here are some cherry-picked samples of other global consequences:
El Niño events are linked with wilder hurricane seasons in the Pacific. This is terrible news for the Philippines, which is already one of the most disaster-struck countries in the world. According to Colorado State University, there have been 21 Category 4 and above (read: holy crap that’s big!) hurricanes in the north Pacific this year alone. This total has obliterated the previous record of 17, which was set during the monster El Niño of 1997. The good news for Florida and southern Texas is that hurricanes in the Atlantic tend to stay home and pursue their hobbies during El Niño months.
Africa may be half the planet away, but the continent has a decent sized serving of interesting weather to expect. Southern Africa is currently in the throes of severe drought, while several East and North African nations are being pelted by heavy rainfall. I mean, can’t we ever just get the RIGHT amount of rain?? Why must it be one extreme or the other?
And, of course, we can’t leave out the main character in this story of wanton weather: MURICA! The following prediction maps for temperature and rainfall have been issued by the National Ocean and Atmospheric Administration (NOAA) on their amazing website, which you can view at www.climate.gov.
What we can tell from this map (aside from the fact that NOAA doesn’t give a hoot about Canada) is that there is a good chance of temperatures being hotter than usual in much of Alaska, Washington and the northern U.S. with dark red indicating a 70%+ probability of hotter than usual conditions. Texas and much of the southern states, on the other hand, may actually have to invest in a sweater or two.
Class Dismissed: Your Take-Home Message Is it the end of the world? Should you start looting your neighborhood grocery store and stocking up on bottled water and canned beans? No. Well, no to the first one: no harm ever came from having an extra can of baked beans, but you may want to prepare your home if you’re in an area that’s at risk of flood or drought. The question on the media’s lips is: is this particularly strong El Niño event proof of climate change and the severe weather we can come to expect from a globally warmer atmospheric environment?
Until we can say what causes the easterly trade winds to die down every two to seven years, we won’t be able to define the relationship between El Niño events and global warming. What is pretty evident – and has been talked about by climate scientists for years – is that a warmer atmosphere contains more moisture (due to greater evaporation) and more energy and is therefore more prone to the development of severe storms.
Your take-home message is this: The atmosphere is like the movie Cloud Atlas: It’s complicated and no matter how closely you study it, you still wonder what the f**k happened in the end. Just remember that the next time you hurl insults at the weatherman for getting the forecast wrong!
And now for a sampling of nature’s finest hurricane videos. Batten down the hatches, because it’s only in the bedroom that it’s fun getting banged like a screen door in a hurricane!
#1: “Hurricane Wilma Hits Southern Florida”
In this awesome science video, watch palm trees head-banging in the wind like a gathering of gangly punk rock kids as hurricane Wilma flattens South Florida in 2005.
#2: “Hurricane Sandy: Timelapse of the Storm from the New York Times Building”
Appreciate a far better vantage point than most New Yorkers had of the storm that caused the Big Apple a serious headache in 2012! Watch Hurricane Sandy roll in and over NYC from the safety of the Times Building. It’s terrifyingly beautiful from this ivory tower.
#3: “Hurricane Katrina Satellite Timelapse”
Katrina’s fender bender with the southern states (2005): This is a must-see for a lesson in hurricane formation, from hazy blip over the Bahamas to a monstrous storm system that swarms and spins like your head after a night of tequila swilling!
This clip from Discovery Channel’s “Raging Planet” shows lightning in super slow motion leave the cloud and connect with the ground. Capturing and watching this footage is helping atmospheric scientists develop a much better understanding of how lightning works. For the rest of us lay folk, it makes for some super interesting visual entertainment!
Video Source: Discovery Channel “Raging Planet” – Lightning. Uploaded by ONE Interpreting on YouTube channel www.youtube.com/watch?v=64WMsNRJvDo
What’s more than ten kilometres (6 miles) long, five times hotter than the surface of an average star and packs in more strokes per second than an over-zealous teenage boy who’s just discovered the joy of internet porn?
Yeah, I know. The picture kind of gives it away doesn’t it?
I have had a complete love affair with thunderstorms for as long as I can remember. I think they are the most awe-inspiring and yet paradoxical demonstration of nature’s prodigious temper and seductive grace. In the space of an hour, the sky can go from an azure blue to the colour of dark slate as giant cumulonimbus clouds broil and swell with latent energy.
Thunderstorms generate all kinds of severe weather: torrential downpours, vicious winds, hail, microbursts and even tornadoes. But they indirectly owe their very name to the one weather feature that claims the lives of, on average, 55 people every year in the United States: lightning!
Source: Global distribution of lightning April 1995 – February 2003 from the combined observations of the NASA OTD (4/95-3/00) and LIS (1/98-2/03) instruments.
Approximately 8 million bolts of lightning strike the Earth every single day, starting 10,000 forest fires annually. In the United States, over 300,000 insurance claims are made against lightning damage every year and the bill for this damage is a staggering $400,000,000.
Yes. Thunderstorms are seriously dangerous systems. I shouldn’t have to tell you that and yet countless golfers are killed by lightning every year. Could there be anything less intelligent than standing in the middle of a wide open space during a thunderstorm with a metal rod in your hand pointed at the sky? With five billion joules of energy surging through a single lightning bolt – enough energy to illuminate a 100 watt bulb for three months – you are picking a fight you simply cannot win.
Against all logic, according to the U.S. National Weather Service, lightning STILL kills more people than tornadoes AND hurricanes combined. What is this madness?
Thunderstorms are extremely busy weather systems. Within a storm cell, legions of water vapour particles are whipped, flung and tumbled around by complex air circulations. Storms themselves are powered by strong updrafts of hot, moist air. This air cools and condenses as it rises through the heights of the lower atmosphere, becoming dense. It consequently loses its upward momentum and sinks and spills out of the rear of the thunderstorm (check out the diagram below).
Photo Credit: “Thunderstorm formation” by NOAA T-storm-mature-stage.jpg. Licensed under Public Domain via Wikimedia Commons
Together, these motions form a continuous cycle of updrafts and downdrafts, which provides the storm system the energy it needs to electrocute golfers, whip cows into the air and blow Dorothy and her dog, Toto, into a parallel reality.
How does this explain what lightning is? Well, it brings us a lot closer to understanding cloud polarization. OMG. What does that mean?
Clouds Can be Bi-Polar Too
Just like batteries, molecules and certain members of your family, clouds too can become bi-polar. Within a thunderstorm, legions of water vapour particles get swirled around violently by the turbulent air circulations. But there are two predominant movements of air in a single cell storm system: hot moist air going up and colder drier air going down.
The water vapour particles being swept up into the cloud smash into those going down and these collisions, while totally invisible to us, are violent enough to cause the descending water particles to literally tear electrons off of the ascending water particles. Electrons are negative. So you see there is a gradual separation of charge within a thundercloud as the descending water particles become negatively charged and the rising water particles (having had an electron or two pilfered from their orbitals) become positively charged.
As a result of particle motions within a thunderstorm, the lower cloud regions become negatively charged and the upper cloud regions positively charged. A positive charge is induced in the ground immediately below the thunderstorm in response to storm’s electric field.
The story doesn’t end here: the polarization of the thundercloud has an effect on its environment, namely, the surface of the Earth and the various objects on it. An electrical field swells outwards from the cloud, caressing the electrons belonging to Earth’s atoms, seducing them into moving. Those who studied physics will remember, electron movement = charge.
The presence of such a massive reservoir of negative charge immediately above the Earth’s surface repels its negatively charged electrons (like repels like), causing an opposing positive charge to build up. In other words, trees, poles, buildings and your head actually develop a static positive charge in the seconds prior to lightning strike. This is probably why people who have been struck by lightning and have lived to tell the tale say that they felt their hair stand on end just before they become a living conductor for 1,000,000,000 volts of electricity.
At some critical juncture, nature notices the thunderstorm’s complete disregard for her love of equilibrium and so a raging streak of electricity discharges between the negative and positively-charged cloud regions. Or the negatively charged lower cloud regions and the positively charged ground immediately below it. And ZAP! You get lightning!
I can feel the cogs of your mind over-heating. So, if you aren’t quite happy with this explanation, then watch the movie Thor. While it doesn’t provide any scientific explanation on lightning genesis whatsoever, Chris Hemsworth is so beautiful you will forget your intellectual torment immediately *swoon*
Guys… you can enjoy watching Natalie Portman at her career low. In a lab coat.
I know I did.
Thunder, Contrary to Kindergarten Mythology, is Not God’s Fart
In spite of my illuminating explanations above – coupled with your homework to watch Thor – the exact physics of lightning generation are not entirely understood. Thunder, on the other hand, is and its explanation makes for a very interesting story. You may want to remember this so you can impress a future date with it…
When lightning tears out of a cloud, the air in the discharge channel heats up from ambient air temperature to a toasty 28,000°C or 50,000°F. That’s approximately five times hotter than the surface of our Sun. And all of this happens in as little as 90 microseconds. I know, right? A yawning chasm of a time denomination.
The problem is, you can’t heat anything up from 10°C to 28,000°C in this short amount of time without some kind of catastrophic consequence. So when lightning shows the ill social etiquette of doing so, the air expands violently, generating a shockwave that explodes outwards from the discharge channel. This shockwave travels faster than the speed of sound – it’s supersonic – so we can’t actually hear it. Dogs probably could, but you’ll have to ask one to be certain.
With distance from the discharge channel, this shockwave slows down and as it does it falls within our audio range. That’s when we hear thunder. I have heard that if you stand close enough to lightning you won’t actually hear it, because the shockwave is supersonic. While this makes sense in theory, human trials are pending. It also explains why, when a storm is very close, the lightning makes a sharp cracking explosive sound while, when further away, you hear the thunder as a low sexy rumble.
Class Dismissed: Your Take-Home Message
More people die of lightning injuries in Florida than anywhere else in America and perhaps even the world. While I’m aware that they have an amazing water world playground at their feet, they also have the highest lightning strike density in the entirety of the United States. Perhaps y’all should bear that in mind the next time you go wind surfing in an electrical storm.
Regardless of where you live, however, if you value your life then don’t swim, don’t bath, don’t chat on a land line, don’t play golf, don’t stand under a tree and don’t go running around like Julie Andrews in a thunderstorm. Otherwise, it won’t just be music the hills are alive with.
Image Source: “Rainbow Ignites” over Grand Canyon, uploaded by Cathy Smart to travel.nationalgeographic.com
Rainbows have enchanted humankind since our very beginnings, leading to the spinning of countless myths and legends about why and what they are. Just about every ancient civilization, culture and religion has its unique explanation of rainbows; all of them creative, but absolutely NONE of them correct. There is no pot of gold.
Aside from the fact that they look like a hippy has barfed across the sky, rainbows have quite a fascinating backstory involving the physics of light, which really isn’t all that complicated! In this blog, we’ll be taking a look at the physical laws and facts that give rise to some spectacular atmospheric masterpieces and a sky that would put a tie-dye T-shirt convention to shame.
The first ingredient on our palette is solar radiation…
You Need Sunshine, On a Cloudy Day!
Sunshine. It’s a simple concept: light from the sun. But one does not simply have interminable nuclear reactions without generating a spectrum of electromagnetic radiation. Our sun is a star and in keeping with the personality of stars, things are positively nuclear beneath its photosphere. These nuclear fusion reactions release a broad range of radiation types (see diagram below), from low energy, long wavelength infrared radiation (left) to the high energy, short wavelength Gamma radiation (right).
Image Source: The Electromagnetic Spectrum – faculty.olympic.edu
Slap bang in the middle of the electromagnetic spectrum is visible light, which only accounts for a narrow portion of the total energy generated by our sun day-after-day. This visible light pours out into space faster than Kris Jenner can say to Bruce “You’re becoming a what!?” covering the vast distance between the Sun and Earth in just 8 minutes and 20 seconds. It then smacks into our atmosphere and all its constituent gas and water vapor molecules. The photons (particles of light) that manage to escape atmospheric collision end their journey at the Earth’s surface, which is what brings warmth to our lives and color to our environment.
Snow White Light and the Seven Composite Colors
As I explained in the blog The Sky Is Only Sometimes Blue, visible (white) light is composed of seven different colors. Each of these colors has a different wavelength and ranges from the lower frequency, longer wavelength color red to the higher frequency, shorter wavelength color violet.
When visible light from the sun strikes a white surface, all of its seven dwarfs, I mean constituent colors get scattered in every direction, which is why we view the object as Snow White, I mean white. If that object is black, however, all of those seven colors become absorbed by the object, which is why you can cook an egg on the dashboard of your black Merc after leaving it in the sun for an hour.
Violet surfaces, like your gay best friend’s curtains, selectively scatter light with a wavelength of around 400 nanometers and absorb the rest. As such, you perceive the color violet (and bad taste) when you look at them.
Blue surfaces, like your lover’s eyes, selectively scatter light with a wavelength of around 450 nanometers. As such, you perceive the color blue and experience inappropriate clenchings in the nethers.
MIRRORS, interestingly enough, reflect all the seven colors of incoming visible light, but instead of scattering them in random directions, they reflect them at precisely the same angle as they arrived at and so the integrity of the image is preserved.
WHAT does this have to do with rainbows?
This discussion is intended to help you understand and appreciate the nature of visible light and the fact that it’s composed of different colors, which are capable of acting independently of each other due to their different wavelengths.
Now it’s when visible light strikes water droplets in our atmosphere that the real magic can begin to happen, potentially making it look like a unicorn wiped its butt on the horizon…
So far, we’ve spoken about light as though it travels in a straight line, which is typically what it does between bouncing off of and being scattered by objects. However, this isn’t the case when it travels through water. When visible light travels from one medium to another – from air into the water – its pathway becomes slightly bent in a process termed “refraction.” This explains why objects under water look so strange: the light that enables us to perceive them is being refracted or bent and this makes your toes (or whatever body part you happen to be scrutinizing) look bigger and closer to you than they really are.
When sunlight passes through a water droplet, it deviates slightly from its incoming direction, because it’s refracted (see diagram below). A portion of this light is then reflected off the far surface of the raindrop. If this angle is at 40° – 42° to the original direction of incoming sunlight, we get a rainbow!
Image Source: What Causes a Rainbow? NASA/NOAA – scijinks.jpl.nasa.gov
So you see, rain droplets not only refract the sunlight that passes through them, they also act as prisms. The reason this process results in a rainbow is because the seven constituent colors of visible sunlight become refracted to different degrees: the shortest wavelength light (violet) becomes refracted the most and so it’s bent the most. The largest wavelength light (red) becomes refracted the least and so it’s bent the least. As such, when white light passes through a water droplet, it becomes split into its seven different personalities, from violet, blue and green to yellow, orange and red!
This is beautifully captured in the following 40-second video:
We can now understand how white visible light, upon passing through water droplets suspended in the atmosphere, is split into its seven constituent colors. The final piece of the puzzle is looking at this process on the large scale. There are billions of water droplets in clouds or mist and each one disperses and refracts the sunlight that hits it. The overall result is a vast display of color in a circular or semicircular arc. Obviously, to us here on Earth, most rainbows would appear to be semi-circular, because the ground gets in the way of us seeing the other half. However, viewed from the air or from the following rare perspective at the top of Zambia’s Victoria Falls, we can see the full glorious monty:
What I haven’t mentioned yet is that perspective plays a major role in our ability to visually enjoy rainbows. The sun has to be behind you and the angle of dispersion – the angle between the incoming sunlight and the direction the refracted light is exiting the raindrop – has to be between 40° and 42°.
Rainbows have this wonderful effect on people: they make us look. They compel us to forget for just a few seconds everything it is we are thinking/worrying/stressing about and look up to the sky and admire. Really, all a rainbow is is water droplets playing with the paths and emotions of sunlight… but they are beautiful and a reminder that God – or whatever deity is or isn’t up there – is in fact a fan of gay people.