M/C exam - part three

What is the typical weather in a mid-latitude anticyclone?

- Generally boring weather - clear, calm • Linger for a while, but can be nice • Trap air near surface (sinking motion) • Blob-like air masses • Air mass stays long can take on characteristics of land it is over

Sketch the cold and warm weather fronts in the mid-latitude cyclone

- If the upper levels are favorable, then the mid-latitude cyclone will continue to develop and bring up mT air in the warm sector and bring down cP air in the cold sector. a. The mT air rises as it moves out ahead of the low helping to deepen the Low pressure center to the east and help it move along b. The cP air sinks behind the system and fills in the Low on the backside also helping to move the system along i. It is this transfer of energy that both strengthens and propagates the mid-latitude cyclone! - Once the mid-latitude cyclone is fully developed, well-defined fronts appear. - As the mid-latitude cyclone reaches maturity, the central pressure will be at its lowest and the occluded front will begin to form (as the cold front catches up to the warm front). - Once the system is occluded (all the warm air is above the cold air) the mass convergence acts to fill in the Low and therefore the pressure increases in the Low and the system decays.

What is the tropical monsoon?

- Seasonal change of trade winds in the tropical regions. - The winds change direction in the winter and summer. This is related to the seasonal moving of the thermal equator (ITCZ). Summer time the ITCZ sits higher around a latitude of 20. Tropical monsoon climate, occasionally also known as a tropical wet climate or tropical monsoon and trade-wind littoral climate in climate classification, is a relatively rare type of climate that corresponds to the Köppen climate classification category "Am". Tropical monsoon climates have monthly mean temperatures above 18 °C in every month of the year and feature wet and dry seasons, as Tropical savanna climates do. Tropical monsoon climates however features its driest month seeing on average less than 60 mm but more than 100 - [total annual precipitation {mm}/25] of precipitation.

Where do the European mid-latitude cyclones form?

- The mid-latitude cyclone is a synoptic scale low pressure system that has cyclonic (counter-clockwise in northern hemisphere) flow that is found in the middle latitudes (i.e., 30 N-55 N) - It is not a hurricane or tropical storm - There is a location (tropics vs. mid-latitudes) and size difference between hurricane and mid-latitude cyclone - Typical size of mid-latitude cyclone = 1500-5000km in diameter - Typical size of a hurricane or tropical storm = 200-1000km in diameter

What is the explanation of the formation of the mirage?

1) inferior mirage (we see the mirage below) light travels on the quickest (laziest) path. because of this when the ground is much hotter than the atmosphere the light is drawn to the ground before reflecting to the observer. 2) superior mirage (we see the mirage above) this is opposite to the inferior mirage and is cause by a temperature inversion in the sky. this is when the surface is much cooler (due to an ice cap, ect) than the atmosphere which causes the light path to bend upwards. we only see one other picture because it is still just the specific light rays, just bent in a different direction.

Give the phases of the negative, cloud to ground lightening

1) step-leader stroke 2) return stroke 3) main stroke

Give the ratio of cloud to ground lightening

20% cloud to surface lightning 80% cloud to cloud lightning

What angle does rainbow located at

42 degrees according to the observer

How does the pressure change prior to the passing and after the passing of the cold front?

A cold front is defined as the transition zone where a cold air mass is replacing a warmer air mass. Cold fronts generally move from northwest to southeast. The air behind a cold front is noticeably colder and drier than the air ahead of it. When a cold front passes through, temperatures can drop more than 15 degrees within the first hour. before passing = falling steadily while passing = minimum, then sharp rise after passing = rising steadily

How do the foehn and the bora form?

A föhn or foehn is a type of dry, warm, down-slope wind that occurs in the lee (downwind side) of a mountain range. Föhn can be initiated when deep low pressures move into Europe drawing moist Mediterranean air over the Alps. It is a rain shadow wind that results from the subsequent adiabatic warming of air that has dropped most of its moisture on windward slopes (see orographic lift). As a consequence of the different adiabatic lapse rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes. Föhn winds can raise temperatures by as much as 14 °C (25 °F) in just a matter of minutes. Central Europe enjoys a warmer climate due to the Föhn, as moist winds off the Mediterranean Sea blow over the Alps. The changeable Bora can often be felt all over Montenegrin Littoral, Dalmatia, Istria, the Slovenian Littoral, Trieste, and the rest of the Adriatic east coast. It blows in gusts. The Bora is most common during the winter. It blows hardest, as the meteorologist Baron Ferdinand von Wrangel explained it by extending Julius Hann's explanation of Alpine katabatic winds to the north Adriatic, when a polar high-pressure area sits over the snow-covered mountains of the interior plateau behind the Dinaric coastal mountain range and a calm low-pressure area lies further south over the warmer Adriatic. As the air grows even colder and thus denser at night, the Bora increases. Its initial temperature is so low that even with the warming occasioned by its descent it reaches the lowlands as a cold wind. The wind takes two different traditional names depending on associated meteorological conditions: the "light bora" (Italian: Bora chiara) is Bora in the presence of clear skies, whereas clouds gathering on the hilltops and moving towards the seaside with rain or snow characterize the "dark bora" (Bora scura).

How does the gust front form?

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 thunderstoms so rapidly. The primary reason is the presence of relatively dry (low humidity) 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 the gust front. The second reason is that the falling precipitation produces a drag on the air, forcing it downward. If the wind following the gust front is intense and damaging, the windstorm is known as a downburst.

How does the mountain wind form?

A mountain breeze and a valley breeze are two related, localized winds that occur one after the other on a daily cycle. They are not the same as katabatic winds, which are larger and stronger. These winds are opposite from each other. While valley breezes occur when the warm air rises up the sides, warm air in a mountain breeze will rise up the middle. Mountain and valley breezes form through a process similar to sea and land breezes. During the day, the sun heats up valley air rapidly while mountain remains relatively cooler. Convection causes it to rise, causing a valley breeze. At night, the process is reversed. During the night the slopes get cooled and the dense air descends into the valley as the mountain wind. These breezes occur mostly during calm and clear weather.

What is the direction of the wind in the case of sea and land breeze?

A sea breeze or onshore breeze is any wind that blows from a large body of water toward or onto a landmass; it develops due to differences in air pressure created by the differing heat capacities of water and dry land. As such sea breezes are more localised than prevailing winds. Because land absorbs solar radiation far more quickly than water, a sea breeze is a common occurrence along coasts after sunrise. By contrast, a land breeze or offshore breeze is the reverse effect: dry land also cools more quickly than water and, after sunset, a sea breeze dissipates and the wind instead flows from the land towards the sea. Sea breezes and land breezes are both important factors in coastal regions' prevailing winds.[1] The term offshore wind may refer to any wind over open water.

What is the temperature gradient?

A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature gradient is a dimensional quantity expressed in units of degrees (on a particular temperature scale) per unit length. Differences in air temperature between different locations are critical in weather forecasting and climate. The absorption of solar light at or near the planetary surface increases the temperature gradient and may result in convection (a major process of cloud formation, often associated with precipitation). Meteorological fronts are regions where the horizontal temperature gradient may reach relatively high values, as these are boundaries between air masses with rather distinct properties. Clearly, the temperature gradient may change substantially in time, as a result of diurnal or seasonal heating and cooling for instance. This most likely happens during an inversion. For instance, during the day the temperature at ground level may be cold while it's warmer up in the atmosphere. As the day shifts over to night the temperature might drop rapidly while at other places on the land stay warmer or cooler at the same elevation. This happens on the West Coast of the United States sometimes due to geography.

Are weather fronts in the tropical cyclones?

A tropical cyclone is a warm-core, low pressure system without any "front" attached, that develops over the tropical or subtropical waters, and has an organized circulation. There are several favorable environmental conditions that must be in place before a tropical cyclone can form. They also carry heat energy away from the tropics and transport it toward temperate latitudes, which may play an important role in modulating regional and global climate.

What are the conditions necessary for the formation of tropical cyclones?

Condition necessary for the formation of tropical cyclone: - They can form only over oceans if see surface temperature is ≥ 26,5°C, except on about 5° wide region on both sides of the equator. Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface, which ultimately recondenses into clouds and rain when moist air rises and cools to saturation.

What is the vertical direction of the air flow in the eye of the tropical cyclone?

Due to the mechanics of a tropical cyclone, the eye and the air directly above it are warmer than their surroundings. The eye is so calm because the now strong surface winds that converge towards the center never reach it. The coriolis force deflects the wind slightly away from the center, causing the wind to rotate around the center of the hurricane (the eye wall), leaving the exact center (the eye) calm.

What optical phenomenon does results in the formation of the halo?

Halo is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Many of these are near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the best known halo types are the circular halo (properly called the 22° halo), light pillars and sun dogs, but there are many more; some of them fairly common, others (extremely) rare. The ice crystals responsible for halos are typically suspended in cirrus or cirrostratus clouds high (5-10 km, or 3-6 miles) in the upper troposphere, but in cold weather they can also float near the ground, in which case they are referred to as diamond dust. The particular shape and orientation of the crystals are responsible for the type of halo observed. Light is reflected and refracted by the ice crystals and may split up into colors because of dispersion. The crystals behave like prisms and mirrors, refracting and reflecting light between their faces, sending shafts of light in particular directions.

Do the path of the tropical cyclones cross the Equator?

Hurricanes and cyclones can't actually form within 4 degrees of the equator, because the Coriolis effect is just too small. Once a tropical revolving storm is formed though, wind determines its movement. There is very little cross-equatorial flow of wind, as the main winds steer the storm away from the equator.

How does the occlusion front form?

In general cold fronts move faster than warm fronts, and may thus catch up with a warm front ahead - the result is an occlusion front There are two types of occluded fronts: warm and cold, depending on whether the air behind the cold front is warmer or cooler than the air ahead of the warm front

What is the direction of the wind just in front of the cold front and behind the cold front?

In the northern hemisphere, a cold front usually causes a shift of wind from southwest to northwest clockwise, also known as veering, and in the southern hemisphere a shift from northwest to southwest (anticlockwise, backing). Cold fronts are stronger in the fall and spring transition seasons and weakest during the summer. When a cold front catches up with the preceding warm front, the portion of the boundary that does so is then known as an occluded front. The cooler and denser air wedges under the less-dense warmer air, lifting it. This upward motion causes lowered pressure along the cold front and can cause the formation of a narrow line of showers and thunderstorms when enough moisture is present. On weather maps, the surface position of the cold front is marked with the symbol of a blue line of triangles/spikes (pips) pointing in the direction of travel. A cold front's location is at the leading edge of the temperature drop off, which in an isotherm analysis would show up as the leading edge of the isotherm gradient, and it normally lies within a sharp surface trough. Cold fronts move faster than warm fronts and can produce sharper changes in weather. Since cold air is denser than warm air, it rapidly replaces the warm air preceding the boundary.

How does the monsoon affect the weather in India and in West-Africa?

India Summer = Humid. Heavy rainfalls between June and September. Winter = Dry and warm Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is sometimes incorrectly used for locally heavy but short-term rains, although these rains meet the dictionary definition of monsoon. The monsoon of western Sub-Saharan Africa is the result of the seasonal shifts of the Intertropical Convergence Zone and the great seasonal temperature and humidity differences between the Sahara and the equatorial Atlantic Ocean. It migrates northward from the equatorial Atlantic in February, reaches western Africa on or near June 22, then moves back to the south by October. The dry, northeasterly trade winds, and their more extreme form, the harmattan, are interrupted by the northern shift in the ITCZ and resultant southerly, rain-bearing winds during the summer. The semiarid Sahel and Sudan depend upon this pattern for most of their precipitation. The southwestern summer monsoons occur from July through September. The Thar Desert and adjoining areas of the northern and central Indian subcontinent heat up considerably during the hot summers. This causes a low pressure area over the northern and central Indian subcontinent. To fill this void, the moisture-laden winds from the Indian Ocean rush in to the subcontinent. These winds, rich in moisture, are drawn towards the Himalayas. The Himalayas act like a high wall, blocking the winds from passing into Central Asia, and forcing them to rise. As the clouds rise their temperature drops and precipitation occurs. Some areas of the subcontinent receive up to 10,000 mm (390 in) of rain annually. The southwest monsoon is generally expected to begin around the beginning of June and fade away by the end of September. The moisture-laden winds on reaching the southernmost point of the Indian Peninsula, due to its topography, become divided into two parts: the Arabian Sea Branch and the Bay of Bengal Branch.

Where do the jet streams form?

Jet streams are currents of air high above the Earth. They move eastward at altitudes of about 8 to 15 kilometers (5 to 9 miles). They form where large temperature differences exist in the atmosphere. An air current is a flowing movement of air within a larger body of air. The two main jet streams are the polar and subtropical jet streams which are due to the large difference of temperature between the regions.

What is the direction of the wind in the jet streams?

Jet streams are fast flowing, narrow, meandering air currents found in the atmosphere of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east).

What is the direction of the mountain wind during daytime and night?

Mountain and valley breezes form through a process similar to sea and land breezes. During the day, the sun heats up valley air rapidly while mountain remains relatively cooler. Convection causes it to rise, causing a valley breeze. At night, the process is reversed.

What is the difference between positive and negative lightning? (not on the exam)

Negative lightning refers to the polarity of the lightning strike. Just like on any battery that has a + (positive) or - (negative) sign. The sign represents the type of charge that comes from that end. With lightning this means there is a transfer of a negative charge from the cloud to the ground in negative lightning strikes. 90-95% of all lightning is negatively charged. It is very dangerous and a typical negative charged bolt is about 300,000,000 volts and 30,000 amps of power. Your typical household lighting bulb is about 120 volts and 12 Amps. These types of strikes only make-up about 5-10% of all lightning strikes. Unlike Negative lightning which originates in the lower to middle of the thunderstorm. Positive lightning originates at the top, some 30-60,000' feet up. Normally, the ground is shielded from this upper positive charge by negative charges in the central part of the storm; however, when upper level winds are stronger than lower level winds and the storm becomes tilted, or when the anvil of the thunderstorm cloud spreads out ahead of or behind the updraft of the thunderstorm, the ground is no longer shielded from this upper charge. If the charge differences between this upper level charge and the ground become too large, a downward-moving positively charged leader can develop. Because this strike has to travel over such a large distance it can be up to 10 times stronger and last 10 times longer than a negative strike. So it can reach 1 billions volts and 300,000 amps!

What is the meaning of the active and passive remote sensing?

Passive sensors measure reflected sunlight that was emitted from the sun. Active sensors have its own source of light or illumination and its sensor measures reflected energy.

Sketch the path of the light inside a water drop in the case of the main rainbow

Rainbows result from refraction of sunlight in falling water droplets plus reflection of the light from the back of the droplet. A rainbow is not located at a specific distance from the observer, but comes from an optical illusion caused by any water droplets viewed from a certain angle relative to a light source. Thus, a rainbow is not an object and cannot be physically approached. Indeed, it is impossible for an observer to see a rainbow from water droplets at any angle other than the customary one of 42 degrees from the direction opposite the light source. - light goes into a water drop and dispersion sends out another color A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.

What is the SI unit of the electric current?

The SI unit for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter.

Sketch the path of the light inside a water drop in the case of the secondary rainbow

The secondary rainbow is about 10° further out from the antisolar point than the primary bow, is about twice as wide, and has its colors reversed. the light of the secondary bow is one-tenth the intensity of that of the primary bow, given the same viewing conditions.

Sketch the charge centrums in a thunderstorm

Thunderstorm, a violent, short-lived weather disturbance that is almost always associated with lightning, thunder, dense clouds, heavy rain or hail, and strong, gusty winds. Thunderstorms arise when layers of warm, moist air rise in a large, swift updraft to cooler regions of the atmosphere. There the moisture contained in the updraft condenses to form towering cumulonimbus clouds and, eventually, precipitation. Columns of cooled air then sink earthward, striking the ground with strong downdrafts and horizontal winds. At the same time, electrical charges accumulate on cloud particles (water droplets and ice). Lightning discharges occur when the accumulated electric charge becomes sufficiently large. Lightning heats the air it passes through so intensely and quickly that shock waves are produced; these shock waves are heard as claps and rolls of thunder. in the mature phase it layers from bottom to top: positive, negative, positive center with a negative surrounding cap/top eventually gets to: positive, negative center, positive top

Sketch the typical path of the tropical cyclones

Typical trajecotory of the tropical cyclones: - At first they move into the direction of north-west, reaching the latitude of 20th° they turn into the direction of north-east

What is the lightening?

You need cold air and warm air. When they meet, the warm air goes up. It makes thunderstorm clouds! The cold air has ice crystals. The warm air has water droplets. During the storm, the droplets and crystals bump together and move apart in the air. This rubbing makes static electrical charges in the clouds. The positive charges in the cloud are at the top. The negative charges are at the bottom. When the charge at the bottom gets strong enough, the cloud lets out energy. The energy goes through the air. It goes to a place that has the opposite charge. This lightning bolt of energy that is let out is called a leader stroke. It can go from the cloud to the ground. Or, a leader stroke can go from the cloud to another cloud. No one is sure why lightning bolts follow a zigzag path as they move. The main bolt or stroke will go back up to the cloud. It will make a flash of lightning. It will also heat the air. The air will spread quickly. It will make the sound we hear as thunder.

What is the position of the orbit of the geosynchronous satellite?

a geosynchronous (geostationary equatorial) satellite is positioned around the equator. the satellite is placed approximately 42,164 km from the center of the earth which causes it to have a rotation period identical to that of the earth. that results in the satellite appearing to not move when observing from the earth's surface.

What is the vertical direction of the air flow in the mid-latitude cyclone and anticyclone?

anticyclone = high pressure with singing and diverging air cyclone = converging air at the surface that rises

Where is the sun when you see rainbow?

behind you

What are the typical clouds related to cold front and to warm front?

cold front: - cumulo-nimbus warm front: - nimbo-stratus - alto-stratus - cirro-stratus - cirro

Do the cold front or the warm front move faster?

cold fronts Cold fronts often come with thunderstorms or other types of extreme weather. They usually move from west to east. Cold fronts move faster than warm fronts because cold air is denser, meaning there are more molecules of material in cold air than in warm air.

What optical phenomenon does results in the formation of the coronas?

diffraction causes a ring around the moon In meteorology, a corona (plural coronae) is an optical phenomenon produced by the diffraction of light from the Sun or the Moon (or, occasionally, bright stars or planets) by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface. In its full form, a corona consists of several concentric, pastel-colored rings around the celestial object and a central bright area called aureole. Coronae differ from halos in that the latter are formed by refraction (rather than diffraction) from comparatively large rather than small ice crystals. Diffraction refers to various phenomena that occur when a wave encounters an obstacle or a slit. It is defined as the bending of light around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle. In classical physics, the diffraction phenomenon is described as the interference of waves according to the Huygens-Fresnel principle.

What is the horizontal extension of the typical tropical cyclones?

horizontal extent is about 500 km

How frequently do the geosynchronous satellites observe a given region of the Earth?

it observes the same location at all times

What regions of the Earth cannot be observed by geosynchronous satellite?

the poles

What is the wind shear?

variation in wind velocity occurring along a direction at right angles to the wind's direction and tending to exert a turning force. Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with change in altitude. Horizontal wind shear is a change in wind speed with change in lateral position for a given altitude.

What is the spatial resolution of the newest generation meteorological satellites?

visible spectrum = 0.5 km other visible/near IR = 1.0 km bands (>2mm) 2.0 km - Visible imagery (B/W and true colour) of surface and clouds - Infra red imagery (multiple wavelengths in IR) cloud top temperature. vertical temperature profile - Sea Surface Temperature - Ocean Chlorophyll content - Land use - Water vapour concentration (integrated through full depth of atmosphere) - Wind speed over ocean - Chemistry (O3, NO2,CO2...)