Intro to Weather and Climate
16 April 2014
Pressure differences create temperature differences that drive small regional wind circulations. There are many different kind of winds because there are different temperatures. There are many types of wind including valley breeze and mountain breeze that are very common. Valley breeze occurs early in the day when the sun is facing the mountain side more than the ground in the valley. The air on the mountain warms up and creates an upslope breeze. A mountain breeze happens when the ground at night is cooled more quickly and is colder than the air above it. The air that is in contact with the ground cools then the air slides down the mountain sides and moves into the valleys. Another type of wind is a chinook wind which can cause clouds to form. A chinook wind is a warm dry downslope wind. Air going up and over the mountain is cooled too and then below the dew point. Moisture that is in the air condenses and then releases heat into the rising air on the left side of the mountain. Since the air is cooled to and below its dew point it creates clouds. Once the air reaches the top and starts to descend it gets compressed and causes the air to get warmer. Santa Ana winds are the most known winds. They come from the Great Basin and blow hot wind across California in the fall. High pressure forms over the Great Basin which develops wind circulation and causes some cool air to move downhill toward the coast. The air is then compressed and then warms. These winds can turn any small fire into a huge fire that's why there are many huge wildfires in California. Winds in the desert can also form dust storms or haboobs which happen a lot in Arizona.
Movement of particles by the wind takes place by a combination of direct wind shear stress and atmospheric turbulence. There are three modes of sediment transport by wind: creep or reptation; saltation, and suspension (Fig. 1). The mode of transport depends primarily on the ratio between particle settling velocity, and hence particle size, and wind shear stress and turbulence intensity. Very small particles (<20 microns) are transported in suspension (tens of km or greater) and are kept aloft by turbulent eddies in the wind. True suspension occurs when the particle settling velocity is very small compared to the turbulence intensity of the wind. Larger particles (20–70 microns) undergo short-term suspension for distances of tens to hundreds of meters; material of sand size (70–1000 microns) is transported mainly in a series of short hops (saltation), in which the vertical component of wind velocity (turbulence) has a minimal effect on particle trajectories. Material coarser than 500 microns in diameter (coarse sand) is transported on surface by reptation and creep. The modes of transport are interdependent: saltating sand particles eject silt- and clay-sized particles into the wind and impact coarse grains that are rolled along the bed. Grains begin to move and sediment is entrained by the wind when fluid forces...
...What is wind?
Wind is basically air in motion that is produced by the uneven heating of the earth’s surface by the sun. As the earth’s surface is made of various land and water formations, it absorbs the sun’s radiation unevenly. Two factors necessary to specify wind is speed and direction.
What causes the wind to blow?
As the sun warms the Earth's surface, even the atmosphere warms too. Some parts of the Earth receive direct rays from the sun all year and are always warm [the equatorial region]. Other places receive indirect rays, so the climate is colder [The Arctic and the Antarctic circles].As warm air is lighter than cold air, it rises. Then the cool air moves in and replaces the rising warm air. This movement of air is what makes the wind blow.
What is a windstorm?
A windstorm is just a storm with high winds or violent gusts but little or no rain.
What is a gust front?
A gust front is the leading edge of cool air rushing down and out from a thunderstorm. There are two main reasons why the air flows out of some thunderstorms so rapidly. The primary reason is the presence of relatively dry air in the lower atmosphere. This dry air causes some of the rain falling through it to evaporate, which cools the air. Since cool air sinks (just as warm air rises), this causes a down-rush of air that spreads out at the ground. The edge of this rapidly spreading cool pool of air is...
...Poetry Analysis on ‘Wind’ by Ted Hughes
The poem ‘Wind’ by Ted Hughes is about the power and the ferocity of wind, the speaker puts forwards how demonic ‘Wind’ can be, it can make everything around him quiver, shiver and fear. The title ‘Wind’ is used as a proper noun, the speaker differentiates the winds in nature to ‘Wind’ he is talking about; the one he is talking about is a demonic creature. In the first stanza, the speaker changes his settings, he starts by saying there is a tempest in the sea and he is stranded in the ship, then he mentions the woods, then the hills and later the fields. The setting of field and the hills is carried forward till stanza three and four. And the poem ends with the setting of house, where the speaker is sitting with his family near the fireplace.
The tone used by the speaker is of awe. He is awestruck by the destruction caused by the wind. ‘Wind’, is given demonic characteristics, it is powerful enough to change the position of the settlements, it has luminous and emerald eyes which move in a random movement and it causes wilful destruction.
Onomatopoeic words are used throughout the poem to intensify the monstrous nature of ‘Wind’ and create auditory imagery of loudness. Words such as ‘crashing’, ‘booming’, ‘bang’, ‘flap’, ‘rang’ and ‘shatter’. Loudness adds up to the monstrous...
...Effects of wind-loading on bridges
Wind is a word that used to describe the motion of the air. It is the natural phenomenon which caused by temperature differential that is resulted from solar radiation. A moving wind that comes in contact with a solid structure will be distracted. Although the wind structure is not fully stopped, it still loses some of its velocity. This is due to the frictional force faced by the wind flow and the surface of the bridge. This phenomenon is actually called wind loading which can give big impact on the structure of the bridge.
Wind gusts that are constantly blows are strong enough to contort the bridge until it collapses. The kinetic energy of the wind is converted into the potential energy in the form of pressure. Both tangential wind loading on bridge surface and pressure can act in any directions can affects the span’s sides, top and bottom surface. This may lead the bridge to flex itself and fluctuates. The flexing alters the wind flow’s angle to the deck where the span’s lateral and torsion displacements altered by the increased wind speed, resulting in creating vibrations which grows to flutter instability. Each fluctuation increases the wind contact with the surface of the span which will build up the twisting motion. In the end, the...
...ODE TO THE WEST WIND
The autumnal west wind sweeps along the leaves and "winged seeds." The seeds will remain dormant until spring. The wind is thus a destroyer and a preserver. The west wind also sweeps along storm clouds. It is the death song of the year. With the night that closes the year will come rain, lightning, and hail; there will be storms in the Mediterranean and the Atlantic. The poet pleads with the westwind to endow him with some of its power, for he feels depressed and helpless. If he were possessed of some of the power of the west wind, he would be inspired to write poetry which the world would read and by which it would be spiritually renewed, just as the renewal which is spring succeeds the dormancy of winter.
Shelley appended a note to the "Ode to the West Wind" when it appeared in the Prometheus Unbound volume in 1820: "This poem was conceived and chiefly written in a wood that skirts the Arno, near Florence, and on a day when that tempestuous wind, whose temperature is at once mild and animating, was collecting the vapours which pour down the autumnal rains. They began, as I foresaw, at sunset with a violent tempest of hail and rain, attended by that magnificent thunder and lightning peculiar to the cisalpine regions."
The note is interesting in that it shows that the poem came out of a specific experience. The imagery...
...By referring to two or three of the poems you have read so far, explain what attitude(s) to the natural world you find in these poems and what leads you to this conclusion
The poems “Wind” and “October Dawn” by Ted Hughes conveys Hughes' attitudes towards the raw power of nature. Through these two poems he presents his belief that although humans have tamed and adapted nature to our purposes, it is still powerful and has the capability of destroying us, and therefore using violent powerful imagery he conveys his awe for nature's monumental, unstoppable strength.
In the poem “October Dawn” Ted Hughes uses the “glass half full of wine left out” as a symbol of civilization which has “dreamed a premonition” that soon the ice age will come and nature will take control once again. The wine has “ice” across its eye, conveying that the wine glass has frost on it and therefore the “ice-age had begun its heave”. The “heave” indicates the massive force of nature going through the land, making it sound powerful and like an unstoppable force against even civilization (that is trying to control nature).
Furthermore, the personification of the “shrubbery” and “ice” creates the effect of relating the “doomed” shrubbery to humans and the “ice” as an army. The “shrubbery” is doomed against the sheer power of nature, just as the lawn was “over trodden and strewn” by it. By stating that the ice has it's “spearhead into place” the poet personifies the ice into an army,...
...Ode to the West Wind
Published in 1820, P.B. Shelley’s Ode to the West Wind, is a poem which allegorizes the role of the poet as the voice of change and revolution. Shelley realizes that he cannot in actual life, rise to the height of imaginative perfection, which was his dream. But it is his bold optimism that he invokes the West Wind to blow the clarion call to the ‘unawaken’d earth’ and to sow the seeds of hope of regeneration.
The poem begins with three stanzas describing the wind's effects upon earth, air, and ocean. The last two stanzas are Shelley speaking directly to the wind, asking for its power, to lift him like a leaf, a cloud or a wave and make him its companion in its wanderings. He asks the wind to take his thoughts and spread them all over the world so that the youth are awoken with his ideas. The poem ends with an optimistic note which is that if winter days are here then spring is not very far.
The poem begins with the poet’s apostrophizing the west wind. The poet uses the epithet ‘wild’ for the West Wind to refer to the untamable, swift, proud, fierce and impetuous spirit of the West Wind. The poet calls it the sustaining air of the autumn season. It is this violent wind which with a rush sweeps and strips off leaves from trees like ghosts escaping away from the spell of an enchanter. The West Wind rushes...
This poem by Shakespeare is divided in two stanzas with nine lines each.
The meaning of the words
Icicle: thin point stick of ice that hangs down from something such as a roof.
Dick: name of person.
Shepherd: someone whose job is to take care of sheep.
Blow: wind moving.
Log: peace of cut trees.
Hall: a room or passage that is just inside the front entrance of a house or public building.
Foul: disgusting, very ugly.
Nightly: every night.
Stare: to look at someone or something for a long time without moving your eyes.
Owl: kind of bird hunts at night and has large eyes.
Greasy: full of oil.
Blow: to remove.
Cough: pushing air out of your throat with tough sound because you are sick.
Parson: the man of the church.
Saw: a tool with sharp points, used for cutting wood.
Brood: to think sadly.
Marian: name of a girl.
Roasted: to cook or be *****d in an oven or over a fire.
Crabs: a wild fruit (green apple).
Hiss: sound (hiss).
Bowl: a wide round container that is open at the top, used for holding liquids, food etc.
Paraphrasing + imagery + figure of speech:
When icicles hang by the wall
The poet describes the ice that hangs down from the roof in a way to describe how cold the weather is. Here we have visual image.
And Dick the shepherd blows his nail
He is talking about a shepherd called Dick who is...