Weather Pix – 08-Feb-2010

Summary: Approximately 2.5 inches of snow fell in the early to mid morning hours. Photographs taken by Derrick Wales at approximately 10:00am 6 miles southwest of Prospect, TN, just north of the AL/TN stateline.

The Rules of Formation

What is rain?
Rain is formed by water vapor molecules as they rise in the atmosphere (by a force such as a low pressure system, cold front, etc). As the molecules rise, they cool and condense and merge together to form a droplet of liquid water. As the droplet gets larger, it gains weight and drops to the ground.

What is Freezing Rain?
Freezing rain is much like sleet – however, the layer of colder air which refreezes the liquid is shallow and very close to ground level. When the liquid passes through this layer, it freezes. The layer can even be shallow enough to where the rain drop will already be splattered on the ground before it freezes.

What is sleet?
Sleet is formed as snowflakes are but travels through a layer of warmer air midway down and melts. When the liquid refreezes, it turns into a tiny bead of ice by the time it hits the ground.

What is Snow?
Snow is formed when liquid vapor molecules freeze and gain weight (ice is heavier than vapor) and fall. Individual snow crystals have 6 sides – many snow crystals form or merge together to form elegant flakes of snow. Their size is determined by the amount of liquid water coating the flakes. In order for snow to form and successfully fall to the ground, temperatures where they form all the way to ground level must remain above freezing.

Dry Snow vs. Wet Snow – The Difference
Dry Snow is formed when temperatures in the troposphere are well below freezing. This is commonplace in the northern US during the winter and more often in Canada. Dry snow can be identified easily – the snowflakes are very small and don’t stick together very well. Try making a large snowball from dry snow and it will fall apart. Wet snow, on the other hand, forms when temperatures in the troposphere are at or just below freezing or there is an unbalanced temperature range in that particular atmospheric layer. Wet snow flakes tend to be larger than dry snow flakes and stick together very well. Wet snow is the best type of snow to use to build snow-men (or snow-women, I won’t discriminate). Wet snow is formed when snowflakes fall and partially melt. This forms a thin layer of liquid water on the snow flake – cold enough to prevent the total melting of the flake but warm enough to not freeze itself. This tends to make the flake sticky. For this reason, wet snow is usually larger. Snowflakes stick together, if wet, as they are falling. This can lead to some snowflakes to appear to look like little snowballs falling from the sky. Some snowflakes have been recorded to reach a half-dollar in size or even larger. The only problem with measuring such immensely sized snowflakes are that they crumble when they hit the ground- eye witness reports have shown flakes to be the size of baseballs or even softballs but it remains unproven. Flakes of great size are infrequent and usually only form when there is a gentle breeze. No wind at all will force the flakes to break apart due to changes in air pressure and resistance. A hard breeze will have the same effect – a shearing effect more or less, but a light wind will keep the flake floating down more slowly but be gentle enough to not shred the flake.

Why are some raindrops large while others are small?
Raindrops merge and grow larger infinitely – all the way until they are on the ground (and even after, research flooding/flash flooding). As they fall, they grow larger until some force breaks them apart – usually air resistance. As the raindrop grows, the resistance from the air forces it to ‘parachute’ itself. The raindrop begins to form a dome shape which eventually ‘pops’ and the raindrop breaks into several smaller raindrops. Small raindrops form from rainclouds that are very high in the atmosphere. They have a longer amount of time to gain speed, merge and break apart. Thus, this is how mist, sprinkles and other tiny drops are formed. Large raindrops are formed from storm clouds which are closer to the ground. They don’t have very far to fall and thus less air resistance to move through. Winds are also a variable in this sense. If winds are strong, the drops will not fall vertically, but at an angle. This slows the drop’s descent somewhat, leaving a little less shearing stress on the drop itself, although strong enough wind can shred the drop itself.

Hope you enjoyed the article and it helped you to better understand why it pours one precipitation sometimes and others at other times. It’s easy to get confused with sleet, snow and freezing rain – especially in our area. Feel free to post any comments, suggestions, questions or concerns. I will respond as soon as I get a chance.

Share this article with someone – send them this pre-shortened link: http://bit.ly/8lf2AI

Accumulated Rainfall – Tennessee Valley Flooding

I’ve gathered some stats for your guys regarding the accumulated rainfall and flash flooding occuring all around the Tennessee Valley area including northwest GA. Be reminded that these are radar estimates and could be a little off but for the most part, it’s accurate. It is a storm total rainfall for rain which fell over the course of the last 7 days.

The Deadly Cycle – How Global Warming Causes Global Warming

The Deadliest Cycle – How Global Warming Causes Global Warming

It is a process known as “feedback”. This process involves some sort of action or event which triggers another event which worsens the first event leading to another secondary event which worsens the first event even more. Confusing? I’ll explain.

A good example of feedback is the melting of the polar ice caps and it’s involvement with global warming. The ice naturally reflects heat energy in the form of radiation back into space. As the ice melts, it covers less area and reveals more water coverage. Less ice enhances the atmospheres heat energy (ice cools air just like it cools your summer drinks). With less ice, the remaining ice melts faster revealing yet more water. Water absorbs heat energy instead of reflecting it. This causes the ice to melt even faster.

There are several types of natural “feedback”: Ice Albedo feedback, water vapor feed back, arctic methane feedback, lapse rate feedback and more. These feedback types enhance global warming and are also, simultaneously, caused by global warming to some extent.

Ice Albedo Feedback
As discussed earlier, Ice Albedo Feedback involves the fact ice reflects more radiation than it absorbs. When ice melts it is replaced by land or water which absorbs more than it reflects. This causes more heat absorption which causes more ice melting which causes yet more absorption. This cycle is never-ending unless affected by an outside source.

Water Vapor Feedback
Water Vapor is a Greenhouse Gas. As the earth warms, more water is evaporated leading to more water vapor. More water vapor leads to more warming which leads to more evaporation thus more water vapor. This cycle is never-ending unless affected by an outside source.

Lapse Rate Feedback
Temperature differences between the lower atmosphere and upper atmosphere is called the Lapse Rate. The higher the temperature of the upper atmosphere, the more radiation is emitted. Thus, if the upper atmosphere (which is supposed to be cold) is heated, it emits much more radiation than if it were cold. This cycle is never-ending unless affected by an outside source.

Methane Release
Warming of the earth has effects both on land and in the ocean in the form of methane release. As the earth’s temperature increases, certain areas of permafrost on the earth melt releasing long frozen and stored methane gas, which in turn, causes more warming since it’s considered a greenhouse gas. This cycle is never-ending unless affected by an outside source.

Cloud Feedback
Some types of clouds, particularly cumulus, are expected to increase in frequency and coverage in the future due to warming and higher, faster evaporation rates. Clouds of this type tend to reflect radiation back down to the ground thus enhancing the lower atmosphere’s ability to retain heat. This increases the earth’s temperature even more causing more cumulus clouds and more back-to-earth radiation reflection. This cycle is never-ending unless affected by an outside source.

A Synopsis on Climate Change

There has been skepticism during the entire lifetime of the theoretical atmospheric anomaly called “Global Warming”. Global Warming is a term coined to describe the unnatural rise of the mean low-level atmosphere temperature over a period of time called climate. Global Warming has also been described as Climate Change although it is not a deserved alias as the earth’s climate often changes in temperature over long periods of time (see ice ages and medieval warming). As such, Global Warming should have been coined as the 21st century Global Warming Trend instead of its current names.

The evidence of Global Warming has seemed to pile-up over the time span of its coined existence. This could be due to the fact that more investigations into the global climate heating has resulted in both expected and unexpected evidence and it could be a result of ongoing changes that take place in real time such as the breaking off and thinning of glaciers. Some of the evidence already observed include a research study by various scientists and reported by the Intergovernmental Panel on Climate Change (IPCC) include a global mean temperature increase of 0.74 ± 0.18 °C (1.33 ± 0.32 °F) over the period of the last century although it seems variations in solar radiation and volcanic activity was the primary contributors before the pre-industrial times before 1950.

Temperature Changes
It is forecasted by the IPCC that the global mean temperature could increase yet another 1.1 to 6.4 °C (2.0 to 11.5 °F) by 2100. The uncertainty in the predicted temperature increases is partially due to the fact that different models have forecasted different amounts of chemicals such as Carbon Dioxide in the atmosphere during varying spans of time. The prediction of 2 °F is a conservative guess but the 11.5 °F increase is also quite possible and would be, of course, the worst case scenario.

The NASA Goddard Space Institute estimated that 2005 was the warmest year globally since dependable and accurate modern satellite temperature monitoring began, exceeding the previous record established in 1998 by only a few hundredths of a degree. The high temperatures recorded in 1998 is thought to be a result of an unusually strong El Niño event – the strongest in over a century.

Since global temperatures have been monitored and recorded, various global locations seem to heat faster than others such as the difference in ocean temperatures relative to land-based atmosphere temperatures. Ocean temperatures rise approximately 0.13 °C relative to land-based atmosphere temperatures which rise an average of 0.25 °C during the course of a decade. Many factors contribute to the difference in temperature increases including the ocean having a vast depth and spread in which temperature is required to increase as well as the effect of evaporation on the air above the ocean. Liquids warm and cool much slower than the air, being more dense, thus the difference in temperature fluctuations. Also, the north hemisphere would warm much faster than the southern hemisphere mainly due to the fact that the northern hemisphere has more land area than does the south. With upper air currents in combination with the difference in temperature, the polar regions would heat much faster than regions closer to the equator, thus the rapid warming and thinning of the polar ice caps in the Arctic and Antarctic Circles. Due to the heat-retaining capacity of the oceans as well as the lifespan of Carbon Dioxide, even if all emissions were to cease the global temperature would continue to rise well after 2100.

Another area which affects the global mean temperature is the effects of “Greenhouse Gases” originally discovered and coined by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in 1896. “Greenhouse Gases” are gases which emit and absorb infrared radiation in the planets atmosphere and enhance the atmosphere’s ability to withhold heat energy. “Greenhouse Gases” include but are not limited to: Water Vapor, Methane, Carbon Dioxide, Nitrous Oxide and Tropospheric Ozone. Higher concentrations of these gases lead to the planet’s atmosphere retaining more heat than it exerts thus raising the global mean temperature. Since the industrial revolution, global carbon dioxide levels have increased by 36% – ¾ of the increase is suspected to be a direct result of the burning of fossil fuels. Evidence extracted from deep ice pockets suggest that carbon dioxide levels are higher than they have been in the last 650,000 years – additional evidence is believed to indicate that levels are actually higher than they have been in the last 20 million years. Although most of the gases mentioned enhance the planets ability to retain heat, some chemicals known as aerosols which are either released naturally, as is the case with volcanoes, or by human sowing as is the case with some CFCs. These chemicals reflect radiation back into space from the upper atmosphere countering the effects of “Greenhouse Gases”. Although this may have been the case up until now, it seems as if the amount of “Greenhouse Gases” such as carbon dioxide and methane are well exceeding the amount of aerosol in the atmosphere. This may have been the reason that extreme global mean temperature increase was delayed during the latter half of the 20th century and only become urgent from the beginning of the new millennium onward. Methods have also been used by scientists to combat global warming indirectly and directly including the use of Biochar, Geoengineering and the like.

Combating Global Warming One Pile at a Time

So what has the world come to? All of a sudden, desperate people clinging to climate change destruction found a new way to combat global warming – burning poop. Aven manure to be exact. A conference was recently held in Boulder, CO on the topic of Biochar – a charcoal formed from burning organic materials in a low-oxygen environment. It is said to be like a “sponge” for atmospheric carbon dioxide. Not only does it soak it up and store it for up to a thousand years, it’s burning in a low-oxygen environment prevents the creation of carbon dioxide when it is burned.

I fully understand every little effort helps against global warming but I don’t think I would ever be too large of a fan of spreading burnt poop all around the world. It’s a great and large endeavor to take on a project of this size and, although it’s impact on the climate would be minimal, those who wish to spread the poop can say that they assisted in the combat against climate change.

As a reminder, every little effort helps. Carpooling, riding a bike instead of driving, driving a hybrid, stopping smoking, planting more trees and other CO2 consuming plants as well as abstaining from burning fossil fuels can all add up when performed on a global scale.

Debunking 2012 Doomsday

2012 – that’s probably the most famous date in history of conspiracies and doomsday dates. We’ve got sources all over predicting cataclysmic events including the “ending” of the Mayan calendar, the predictions of “prophets” such as Nostradomus and Hopi, the chinese and the I Ching as well as others. Oh, let’s not forget the abominable Planet X, Nibiru. Seriously? Thats a lot of evidence. Even Hollywood has become fortune tellers: Armageddon? Knowing? Doomsday? The Day the Earth Stood Still? They’ve gotta be telling the truth, I mean, it’s Hollywood.

Climate change – ugh, we can’t forget Climate Change. Global warming is a warning to us all. Not really a warning – more like a heads up…”enjoy it while you can” I guess. So, with all this evidence, I believe it should be posted scientifically. If it’s not analyzed thoroughly, then it’s not scientific. If it’s not scientific, then it’s just a belief (and we know where unfactuated beliefs get us).

The Mayan Calendar
First off, the Mayans did not come up with that calendar – they adopted it from their ancestors of the region as did the other like cultures of their time. Secondly, the Mayan calendar was one of the most “off” calendars in history. It wasn’t even as accurate as the Julius calendar (and that’s saying something). The Mayan months were 20 days long (sometimes called 20 day weeks) and a “solar” year consisted of 18 of them. Yes, solar is in quotations. It’s not really a solar year – their calendar days were integers. As we know, nothing on earth ticks in exact integers for the same reason there is never a perfect circle no where in existance. So, for this, a year to them was 365 days (seems right….right?). The day, in fact, is not 365 days (and if you know what a leap year is, you’ll know why it’s not 365. It’s more like 365.25 (approx). So in other words, with their days as long as they are, doomsday has already passed. But, lets say that their calendar WAS accurate and their calendar “ends” in 2012 – what “ends” is not their calendar. The Mayan calendar DOES NOT END IN 2012. Only a cycle of the calendar, the 13th cycle to be exact, ends. What happens when it does? Destruction? Calamity? 2013? Yep, 2013 will come around just like 2012 did, just like 2009 did and so on. Not quite proving it? The 14th Mayan cycle starts as soon as the 13th ends on December 21st, 2012.

Nostradamus
What a name. Perhaps one of the most famous “prophets” of all time (except for maybe Matthew, Mark, Luke and John…and eh, we’ll throw Muhammed in there too). Nostradamus 1) was a severe drug addict, 2) practiced visioning with “demons” and admitting himself and in his writings that we was surely going to hell for what he was doing, 3) wrote so damned funny that anything he said could be interpreted to mean anything and lastly, 4) predicting events that take place AFTER 2012. Now why the hell would he predict things that happen TO MANKIND if he predicted the world would end in 2012? I’ll let you talk to yourself about that one…..

Knowing
It was a movie. It was Hollywood and special effects. First off, if our Sun was going to explode or erupt with this gigantic solar flare, we would be seeing the same event in stars which are approximately the same size as our sun and around the same age. We don’t. And there are thousands of them. The chances? Do the math. 5 Billion Years, Thousands of Sun-like stars, 0 events like that in Knowing.

Pole Shift
So you think the poles are all of a sudden going to flip or shift or whatever? Get over yourself, this isn’t science fiction. Do you realize how much energy it would take to shift our poles? If a source of that much energy was upon us 1) we would already know and 2) we’d be gone long before the poles shifted. We’re talking enough energy to permanently warp our magnetosphere. That’s like having enough energy to shove the Earth into Mars. Anything with that much force would kill us all LONG before our poles moved. Yes, the poles move naturally – but slowly. It may take thousands if not hundreds of thousands of years for our poles to move, but they do move, only slowly.

Nibiru
And finally, we come to Nibiru, the tenth planet coined, Planet X. First off, Nibiru isn’t the tenth planet. Nibiru isn’t a star. Nibiru…..doesn’t exist. If anything were close enough to be able to collide with earth in 3 years (as Nibiru is supposably forecasted to do) and is massive enough to completely wipe the planet clean of life, then we would most definately know about it by now. Think the government is covering it up? Well, there’s one aspect of life the government CANT cover up and that’s astronomy. Some of the best astronomers in the world with some of the best equipment in the world are amateur astronomers, people like you and me sitting at home looking through a telescope. If there was something out there, with over a million amateur astronomers out there all over the world, we’d already know about it.

Climate Change
Climate change. Yeah, it’s bad. Most likely, it’ll kill 30% or so of all species on earth. Nothing will be the same. Humans will survive it though. As will the planet. Period.

Shared Beliefs

I was just browsing around and came across a good post by a well known, albeit local, personality. Dan Satterfield is but a television meteorologist to some but an inspiration for others. Since 1995, I’ve been watching his forecasts and enjoying severe weather coverage with his excitable antics. The post I am mentioning here came from his blog, Wild Wild Weather Journal. It’s a good and startling read when you contrast today with tomorrow (figuratively).

Dan’s Wild Wild Weather Blog
Dan’s “Climate Change In Your Backyard” Blogpost

Gravity Waves – A Closer Look

Gravity Waves
In fluid dynamics, gravity waves are waves generated in a fluid medium or at the interface between two media (e.g. the atmosphere and the ocean) which has the restoring force of gravity or buoyancy.

When a fluid element is displaced on an interface or internally to a region with a different density, gravity tries to restore the parcel toward equilibrium resulting in an oscillation about the equilibrium state or wave orbit. Gravity waves on an air-sea interface are called surface gravity waves or surface waves while internal gravity waves are called internal waves. Wind-generated waves on the water surface are examples of gravity waves, and tsunamis and ocean tides are others.

Wind-generated gravity waves on the free surface of the Earth’s ponds, lakes, seas and oceans have a period of between 0.3 and 30 seconds (3 Hz to 0.033 Hz). Shorter waves are also affected by surface tension and are called gravity-capillary waves and (if hardly influenced by gravity) capillary waves. Alternatively, so-called infragravity waves — which are due to subharmonic nonlinear wave interaction with the wind waves — have periods longer than the accompanying wind-generated waves.

Atmospheric Dynamics on Earth
Since the fluid is a continuous medium, a traveling disturbance will result. In the earth’s atmosphere, gravity waves are important for transferring momentum from the troposphere to the mesosphere. Gravity waves are generated in the troposphere by frontal systems or by airflow over mountains. At first waves propagate through the atmosphere without affecting its mean velocity. But as the waves reach more rarefied air at higher altitudes, their amplitude increases, and nonlinear effects cause the waves to break, transferring their momentum to the mean flow.

This process plays a key role in controlling the dynamics of the middle atmosphere.

The clouds in gravity waves can look like Altostratus undulatus clouds, and are sometimes confused with them, but the formation mechanism is different.

Quantitive Description
The phase speed c of a linear gravity wave with wavenumber k is given by the formula

where g is the acceleration due to gravity. When surface tension is important, this is modified to

where g is the acceleration due to gravity, σ is the surface tension coefficient, ρ is the density, and k is the wavenumber of the disturbance.
Since c = ω / k is the phase speed in terms of the frequency ω and the wavenumber, the gravity wave frequency can be expressed as

The group velocity of a wave (that is, the speed at which a wave packet travels) is given by

and thus for a gravity wave,

The group velocity is one half the phase velocity. A wave in which the group and phase velocities differ is called dispersive.

The Generation of Waves by Wind
Wind waves, as their name suggests, are generated by wind transferring energy from the atmosphere to the ocean’s surface, and capillary-gravity waves play an essential role in this effect. There are two distinct mechanisms involved, called after their proponents, Phillips and Miles.

In the work of Phillips[1], the ocean surface is imagined to be initially flat (‘glassy’), and a turbulent wind blows over the surface. When a flow is turbulent, one observes a randomly fluctuating velocity field superimposed on a mean flow (contrast with a laminar flow, in which the fluid motion is ordered and smooth). The fluctuating velocity field gives rise to fluctuating stresses (both tangential and normal) that act on the air-water interface. The normal stress, or fluctuating pressure acts as a forcing term (much like ‘pushing’ is a forcing term for a swing). If the frequency and wavenumber of this forcing term match a mode of vibration of the capillary-gravity wave (as derived above), then there is a resonance, and the wave grows in amplitude. As with other resonance effects, the amplitude of this wave grows linearly with time.

The air-water interface is now endowed with a surface roughness due to the capillary-gravity waves, and a second phase of wave growth takes place. A wave established on the surface either spontaneously as described above, or in laboratory conditions, interacts with the turbulent mean flow in a manner described by Miles[2]. This is the so-called critical-layer mechanism. A critical layer forms at a height where the wave speed c equals the mean turbulent flow U. As the flow is turbulent, its mean profile is logarithmic, and its second derivative is thus negative. This is precisely the condition for the mean flow to impart is energy to the interface through the critical layer. This supply of energy to the interface is destabilizing and causes the amplitude of the wave on the interface to grow in time. As in other examples of linear instability, the growth rate of the disturbance in this phase is exponential in time.

This Miles-Phillips Mechanism process can continue until an equilibrium is reached, or until the wind stops transferring energy to the waves (i.e. blowing them along) or when they run out of ocean distance, also known as fetch length.

This article was not my own. I do not take credit for this article, in whole or part. Article was derived from a collaborative effort from Wikipedia.