Biology Power Point Presentation "Coral Reefs" (Example Included)

This is an example of an excellent submission. I have shortened the file. If there are differences between what is in this presentation and what is stated in our directions, use the directions. This example is provided only to give you a “feel” for what the presentation should look like. Prof. Whitford

Good morning (afternoon) everyone. My name is xxxx xxxx and today I will be talking to you about something that you have most likely seen and experienced at one time or another-- fog. If asked to define fog, most people would probably say that it is an annoying weather occurrence that ties up traffic and creates other travel troubles. While this is true, fog can wreak havoc on the highways and skyways, such a definition really only provides a small piece of the much bigger fog picture. Fog is actually a fascinating weather phenomenon that comes in many different varieties. That is right; there are different types of fog. And believe it or not, fog is not all bad. In fact, it can be quite beneficial.

In order to gain a better understanding of fog, we will take a look at the different types of fog, how and where they typically form, their characteristics, as well as the hazards and benefits associated with them. Before we start exploring the different types of fog that form, though, we need to first understand what fog is. By definition, fog is a cloud, composed of visible water droplets or ice crystals, that forms at the ground, impeding visibility (Ahrens, 2007, p. 110; Wood, 2001, p. 265). In order for the visible water droplets or ice crystals to be considered fog, visibility has to be reduced to less than .62 miles (about 3,000 feet) (Ahrens, 2007, p. 110; Pretor-Pinney, 2006, p. 81). Fog is defined as dense when visibility is reduced to less than a quarter mile (about 1,300 feet) (Ahrens, 2007, p. 110). When visibility is greater than 3,000 feet, visible water droplets in the air are defined as mist (Pretor-Pinney, 2006, p. 81).

One of the most common types of fog that forms when air is cooled is radiation fog. Radiation fog forms at night when the earth’s surface releases the heat it has absorbed during the day (NOAA, 2007, para. 1). This process is known as radiational cooling. As the ground cools through radiational cooling, so does the air directly above it (Ahrens, 2007, p. 111). If this air is moist, it will become saturated as it cools, condensation will occur and fog will form (NOAA, 2007, para. 1). Because this type of fog forms from the ground up, it is also known as ground fog (Ahrens, 2007, p. 111). Radiation fog is only found over land (water surfaces do not radiate heat like land surfaces do), and can range anywhere from three to 1,000 feet in depth (Wood, 2001, p. 265; NOAA, 2007, para. 1).

In order for radiation fog to form, it must be a clear and relatively calm night (Ahrens, 2007, p. 111). When the night is clear, the earth’s surface cools quickly, setting the stage for fog formation (Pretor-Pinney, 2006, p. 84). However, when clouds are present, they re-radiate heat back towards the earth’s surface, inhibiting the formation of fog (Pretor-Pinney, 2006, p. 84). In addition to clear skies, winds need to be calm or very mild in order for radiation fog to form. Calm conditions are important because the absence of winds allows the moist air to remain in contact with the surface, but mild winds (less than 5 knots) actually help promote the formation of radiation fog by stirring the air (Ahrens, 2007, p. 111; Wood, 2001, p. 265). This stirring enhances the interaction between the cool air and the moist air, spreading the cooling through the moist air (Reynolds, 2005, p. 85). It also causes more of the moist air to come into contact with the surface, enabling cooling to occur more quickly (Ahrens, 2007, p. 111). When winds are stronger than five knots, however, radiation fog usually does not form because the winds mix the moist air with drier air above, keeping the moist air from becoming saturated.

In addition to clear and relatively calm conditions, there are some other factors that influence the formation of radiation fog. Radiation fog tends to form more easily on long nights, when there is more time for the air to cool (Ahrens, 2007, p. 111). Therefore, it is more often seen in the fall and winter when the nights are longer and cooler (Reynolds, 2005, p. 86). It is also more likely to form in low-lying areas (Ahrens, 2007, p. 111). In fact, radiation fog that forms in low-lying areas such as valleys has its own name. Appropriately, it is called valley fog (Ahrens, 2007, p. 111). Fog often forms in valleys because nighttime cooling causes air found at the tops of mountains and hills to sink into the valleys below, adding more fuel (cold air) to promote the formation of fog (Ahrens, 2007, p.111). The Central Valley area of California is extremely susceptible to this type of fog (Ahrens, 2007, p. 112).

As previously mentioned, advection fog looks similar to radiation fog. However, because advection fog involves moving air, it can be distinguished from radiation fog by noting its horizontal movement (NOAA, 2007, para 3). Advection fog also differs from radiation fog in that it can form at anytime of the day, unlike radiation fog, which only forms at night (Wood, 2001, p. 265). Additionally, advection fog can form even when winds are stronger (up to 15 knots) (Wood, 2001, p. 265). Like radiation fog, though, advection fog tends to burn off as the day progresses. Typically, this happens as the wind carries the advection fog over warmer land (Ahrens, 2007, p. 112).

Another difference between radiation fog and advection fog is that advection fog is most often seen in coastal areas or at sea (Wood, 2001, p. 265). When advection fog forms at sea it is called sea fog (Wood, 2001, p. 265). Advection fog often forms over the oceans because winds move warmer sea air over colder portions of water (Ahrens, 2007, p. 112). When that happens, the warm air is cooled, reaches saturation and fog develops. Areas where the ocean waters are always cooler tend to see much more advection fog than other areas (Reynolds, 2005, p. 87). This is the case along the Pacific Coast of the United States.

Advection fog is frequently seen along the Pacific Coast because sea surface temperatures are much cooler by the coast than they are further out to sea (Ahrens, 2007, p. 112). Because of that, when the winds carry the warmer ocean air over the coastal waters, fog forms. Another common place to find advection fog is in the Grand Banks area off the coast of Newfoundland. The Grand Banks is an area where the cold Labrador Current flows next to the much warmer Gulf Stream (Reynolds, 2005, p.87; Ahrens, 2007, p. 112). As the warmer air above the Gulf Stream is carried over the colder waters of the Labrador Current, advection fog forms (Ahrens, 2007, p. 112). During the summer months this occurs frequently, resulting in two out of every three days being foggy (Ahrens, 2007, p. 112).

Advection fog, while hazardous, especially to marine vessels, can be extremely beneficial. In fact, there are some countries that actually welcome the fog, harvesting it for its water content (Oman, 2005, p. 71). Here is how it works—Large nylon nets are set up in areas where the fog is driven inland by the winds (United Nations Environment Programme [UNEP], 1997, para. 1). When the fog hits the nets, the water droplets that make up the fog collect on the nets (UNEP, 1997, para. 3). Once enough water droplets have collected, they form larger droplets that fall into a collection system below the nets (UNEP, 1997, para. 4). Through this process, about thirty percent of the water content in fog can be collected (Oman, 2005, p. 74). One place this is occurring is in Chungungo, Chile. This coastal village is extremely dry, and for much of its existence had to have water trucked in in order to sustain its population (Oman, 2005, p. 71). However, since implementing a fog harvesting program in 1987, the village has become self-sufficient, relying only on the fog to produce the water that the community needs (Oman, 2005, p. 71).

While advection fog is common near the coast, upslope fog is seen in hilly or mountainous areas (Ahrens, 2007, p. 112). Upslope fog, like radiation and advection fog, forms when air is cooled. However, the air associated with upslope fog has its own way of cooling. Upslope fog forms when moist air is gently pushed up a sloped area (e.g., mountain or hillside) by mild winds (NOAA, 2007, para. 6). As the moist air is moved upwards, it expands and cools (Ahrens, 2007, p. 113). As the air cools, it becomes saturated, condensation occurs and fog forms.

Upslope fog typically covers a large area, sometimes extending for hundreds of miles, and can be quite dense (Burroughs, 1996, p. 183; Wood, 2001, p. 265). It can also last for several days, clearing only when the winds pushing the moist air upwards end (Ahrens, 2007, p. 113; Wood, 2001, p. 265). Upslope fog can occur in any hilly or mountainous area but is most common during the winter and spring along the eastern side of the Rocky Mountains (Ahrens, 2007, p. 112, NOAA, 2007, para 6). During those times, cold, moist air, moving east to west, encounters the Rocky Mountains and is pushed upwards. As the air is forced up, it expands and cools, eventually reaching saturation. At that point, upslope fog forms. This same process is seen in Australia where moist sea is pushed up the Great Dividing Range, resulting in extensive areas of upslope fog (Burroughs, W. J., Crowder, B, Robertson, T., Vallier-Talbot, E. & Whitaker, R., 1996, p. 183).

Frontal fog, also known as precipitation fog, forms when warm raindrops pass through colder air masses, causing the raindrops to evaporate into the colder air (Ahrens, 2007, p. 116). When this happens, the colder air becomes saturated, condensation takes place and frontal fog forms. Frontal fog is usually associated with warm fronts (Wood, 2001, p. 265). The warm precipitation associated with the warm front falls into the colder air just ahead of the front, resulting in fog formation (Ahrens, 2007, p. 116). While this type of fog is usually associated with warm fronts, it can also develop behind a cold front or along a stationary front (Ahrens, 2007, p. 116; Wood, 2001, p. 265). When frontal fog does form it tends to be quite dense and generally covers a large area (Wood, 2001, p. 265). It may also last for an extended period of time (Wood, 2001, p. 265). Because of its density, size and duration, frontal fog is often responsible for the closure of airports (Wood, 2001, p. 265).

When fog disperses, it usually clears from the ground up (Ahrens, 2007, p. 111). Sometimes, though, fog does not completely clear. Instead it may only lift from the ground up to about 500 feet, leaving a layer of fog above (Ahrens, 2007, p. 112). When this happens, the remaining fog is called fog stratus or high inversion fog (Burroughs, W. J., Crowder, B, Robertson, T., Vallier-Talbot, E. & Whitaker, R., 1996, p. 184; Ahrens, 2007, p. 112). When fog stratus forms, it typically clears by late-morning but, in some cases, when the fog stratus is especially dense, it can trigger a viscous cycle of fog formation that can last for days or even weeks (Burroughs, W. J., Crowder, B, Robertson, T., Vallier-Talbot, E. & Whitaker, R., 1996, p. 184; Ahrens, 2007, p. 112). When this happens, the fog, due to radiational cooling, forms again at ground level during the night (Ahrens, 2007, p.112). During the day, the ground level fog once again clears, leaving just the fog stratus. As mentioned previously, this process can go on for days or even weeks (Ahrens, 2007, p. 112).

Ahrens, C.D. (2007). Meteorology today: An introduction to weather, climate, and the

environment (8th ed.). Belmont, CA: Thomson Brooks/Cole.

Burroughs, W. J., Crowder, B, Robertson, T., Vallier-Talbot, E. & Whitaker, R. (1996).

Weather. Sydney, Australia: Weldon Owen.

Ellrod, G. P. & Lindstrom, S. (n.d.). Performance of satellite fog detection techniques

with major, fog-related highways accidents. Retrieved October 19, 2007 from http://www.nwas.org/ej/pdf/2006-EJ3.pdf

Gajananda, K., Dutta, H. N. & Lagun, V. E. (2007). An episode of coastal advection fog

over east Antarctica. Current Science, 93 (5), 654-685. Retrieved October 15, 2007 from http://64.233.169.104/search?q=cache:JzzwljUBXuEJ:www.ias.ac.in/
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National Snow and Ice Data Center [NSIDC]. (n.d.). Ice fog. Retrieved October 15, 2007

from http://nsidc.org/cgi-bin/words/word.pl?ice%20fog

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http://www.nssl.noaa.gov/primer/defs/supercool.html

NOAA. (2007). Types of fog. Retrieved October 2, 2007, from

http://www.crh.noaa.gov/jkl/?n=fog_types

Oman, A. H. (2005). Weather: Nature in motion. Washington, D.C.: National Geographic

Society.

Phillips, D. (1996). Ice fog: The frigid veil of winter. Canadian Geographic, 116 (2), 18.

Retrieved October 15, 2007 from Academic Search Premier database.

Pretor-Pinney, G. (2006). The cloudspotter’s guide: The science, history and culture of

clouds. New York, NY: Penguin Group.

Reynolds, R. (2005). Guide to weather. Buffalo, NY: Firefly Books.

Rozell, N. (1997). Ice fog a product of temperature, topography, dogs. Retrieved October

15, 2007 from http://www.gi.alaska.edu/ScienceForum/ASF13/1319.html

United Nations Environment Programme. (1997). Fog harvesting. Retrieved October 22,

2007 from http://www.oas.org/dsd/publications/Unit/oea59e/
ch12.htm#1.3%20fog%20harvesting

Wagner, R. L. & Adler, B. (1997). The weather sourcebook (2nd ed.). Old Saybrook, CT:

The Globe Pequot Press.

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weather. New York: Vintage Books.

Wood, R. A. (Ed.). 2001. The weather almanac (10th ed.). Detroit: Gale Group.

Slide Two- Fog

The Royal Meteorological Society. (1968). “Radiation fog over Bute Park, Cardiff,

Wales” [online image]. Retrieved November 1, 2007 from http://www.rmets.org/cloudbank/detail.php?ID=42

NOAA. (n.d.). “The Golden Gate Bridge shrouded in advection fog” [online image].

Retrieved November 1, 2007 from http://www.crh.noaa.gov/jkl/?n=fog_types

Tardif, R. (2004). “Cars in fog” [online image]. Retrieved November 1, 2007 from

http://www.rap.ucar.edu/staff/tardif/Documents/CUprojects/ATOC5600/fog_characteristics.htm

BBC. (2006). “Airplane on runway in fog” [online image]. Retrieved November 1, 2007

from http://news.bbc.co.uk/2/hi/uk_news/6202349.stm

Slide 3- What is fog?

Choi, A. (2005). “Morning fog” [online image]. Retrieved November 1, 2007 from

http://www.trekearth.com/gallery/North_America/United_States/Midwest/Ohio/Cincinnati/photo161398.htm

Slide 4- Water Vapor

Understanding relative humidity. (n.d.). “Water vapor and air temperature” [online

image]. Retrieved November 1, 2007 from http://www.warren-wilson.edu/~physics/PhysSci/humidity_Pressure/UnderstandingRH.html

Slide 5- How Fog Forms

Plymouth State Weather Center. (n.d.). “Condensation nuclei” [online image]. Retrieved

November 1, 2007 from http://vortex.plymouth.edu/precip/

Slide 6- The Different Types of Fog

Von Weber, W. (2007). “Mysterious fog” [online image]. Retrieved November 1, 2007

from http://www.trekearth.com/gallery/photo687225.htm

Slide 7- Radiation Fog

Bleath, D. (n.d.). “Radiation fog near Ellsmere Wharf” [online image]. Retrieved

November 1, 2007 from http://www.bbc.co.uk/shropshire/features/
2005/01/calendar_weather_gallery_32.shtml

Rogers, K. (n.d.). “How radiation fog forms” [online image]. Retrieved November 1,

2007 from http://keithrogershome.com/Chap7CldsPcpnFog.html

Slide 8- Ideal Conditions for Radiation Fog Formation

Wood, E. (2005). “Fog at night” [online image]. Retrieved November 1, 2007 from

http://emiliewood.com/index.php?cat=5

Slide 9- Valley Fog

Fogged. (2006). “Valley fog” [online image]. Retrieved November 1, 2007 from

http://www.flickr.com/photos/jensenl/124543675/

Heidorn, K. C. (2002). “How valley fog forms” [online image]. Retrieved November 1,

2007 from http://www.islandnet.com/~see/weather/almanac/arc2002/alm02sep.htm

Slide 10- The Hazards of Radiation Fog

BBC. (2005). “Twenty-one injured in fog crash” [online image]. Retrieved November 1,

2007 from http://news.bbc.co.uk/2/hi/uk_news/england/kent/4564439.stm

Slide 11- How Radiation Fog “Burns Off”

Finken, R. (n.d.). “Fog lifting over autumn foliage” [online image]. Retrieved November

1, 2007 from http://www.jupiterimages.com/

popup2.aspx?navigationSubType=itemdetails&itemID=22820275

Slide 12- Advection Fog

Miller, B. (2005). “Advection fog at night” [online image]. Retrieved November 1, 2007

from http://www.rjma.com/flight/airwaves/vol2-19t.htm

Rogers, K. (n.d.). “How advection fog forms” [online image]. Retrieved November 1,

2007 from http://keithrogershome.com/Chap7CldsPcpnFog.html

Slide 13- Advection Fog vs. Radiation Fog

No image

Slide 14- Sea Fog

Bright fog. (2006). “Sea fog” [online image]. Retrieved November 1, 2007 from

http://www.flickr.com/photos/oneeighteen/144574712/

Slide 15- Areas Prone to Advection Fog

NOAA. (n.d.). “Grand Banks advection fog” [online image]. Retrieved November 1,

2007 from http://www.photolib.noaa.gov/700s/wea03113.jpg

Slide 16- Advection Fog Over Inland Areas

NASA. (n.d.) “Gulf Coast advection fog” [online image]. Retrieved November 1, 2007

from http://virtualskies.arc.nasa.gov/weather/tutorial/tutorial4.html

Slide 17- Fog Harvesting

LaCroix, P. (1998). “Fog harvesting nets” [online image]. Retrieved November 1, 2007

from http://www.idrc.ca/en/ev-5077-201-1-DO_TOPIC.html

Fog-harvesting for water. (2003). “More fog harvesting nets” [online image]. Retrieved

November 1, 2007 from http://www.scienceinafrica.co.za/2003/march/fog.htm

Slide 18- Environmental Benefits

Luong, Q. T. (n.d.). “Redwood trees in fog” [online image]. Retrieved November 8, 2007

from http://www.terragalleria.com/parks/np-image-lf.redw4283.html

Slide 19- Upslope Fog

NOAA. (n.d.). “Upslope fog” [online image]. Retrieved November 8, 2007 from

http://www.crh.noaa.gov/jkl/?n=fog_types

Rogers, K. (n.d.). “How upslope fog forms” [online image]. Retrieved November 1, 2007

from http://keithrogershome.com/Chap7CldsPcpnFog.html

Slide 20- Areas Prone to Upslope Fog

Ritter, M. (n.d.). “Upslope fog in the Rocky Mountains” [online image]. Retrieved

November 8, 2007 from http://www.uwsp.edu/geo/faculty/ritter/glossary/s_u/upslope_fog.html

Slide 21- Evaporation-Mixing Fog

NOAA. (n.d.). “Steam fog” [online image]. Retrieved November 1, 2007 from

http://www.crh.noaa.gov/jkl/?n=fog_types

NOAA. (n.d.). “Frontal fog” [online image]. Retrieved November 1, 2007 from

http://www.crh.noaa.gov/jkl/?n=fog_types

Slide 22- Steam Fog

NOAA. (n.d.). “Steam fog on lake” [online image]. Retrieved November 1, 2007 from

http://www.photolib.noaa.gov/700s/wea02057.jpg

NASA. (2006). “How steam fog forms” [online image]. Retrieved November 1, 2007

from http://asd-www.larc.nasa.gov/SCOOL/layer.html

Slide 23- Frontal Fog

Heidorn, K. C.. (2002). “Precipitation fog” [online image]. Retrieved November 1, 2007

from http://www.islandnet.com/~see/weather/almanac/arc2002/alm02sep.htm

Slide 24- Fog Dispersal Systems

NOAA. (n.d.). “Fog at Salt Lake City airport” [online image]. Retrieved November 1,

2007 from http://newweb.wrh.noaa.gov/slc/aviation/

Slide 25- Clearing Fog With Dry Ice

North American Interstate Weather Modification Council. (n.d.). “Dry ice seeding”

[online image]. Retrieved November 14, 2007 from http://www.naiwmc.org/4dcgi/GetContentRecord/PB-893

Slide 26- Ice Fog

NOAA. (n.d.). “Ice fog” [online image]. Retrieved November 1, 2007 from

http://www.crh.noaa.gov/jkl/?n=fog_types

Slide 27- Ice Fog: A Man-Made Problem?

Seaward’s ice box. (n.d.). “Ice fog formed by power plants” [online image]. Retrieved

November 1, 2007 fromhttp://www.geocities.com/abaccola/winter.html

Seaward’s icebox. (n.d.). “Ice fog formed by cars” [online image]. Retrieved November

1, 2007 from http://www.geocities.com/abaccola/winter.html

Slide 28- The Beauty of Ice Fog

Robock, A. (2004). “Halo in ice fog” [online image]. Retrieved November 1, 2007 from

http://climate.envsci.rutgers.edu/Antarctica/Halo9.28.04.JPG

Slide 29- Freezing Fog

NOAA. (n.d.). “Freezing fog” [online image]. Retrieved November 1, 2007 from

http://www.crh.noaa.gov/jkl/?n=fog_types

Slide 30- Freezing Fog And Rime

Journal. (2007). “Freezing fog and rime” [online image]. Retrieved November 14, 2007

from http://www.disciplesnw.org/yakama/journal.html

Shafer, J. (n.d.). “Elongated rime” [online image]. Retrieved November 14, 2007 from http://www.met.utah.edu/galleries/home_page_images/rimecolor_mwn.JPG/photo_view

Slide 31- Frog Stratus

Fog, dew and frost. (2005). “Fog stratus” [online image]. Retrieved November 14, 2007

from http://www.theairlinepilots.com/met/fog.htm#Fog%20Stratus

Slide 32- Feeling Foggy (Closing Slide)

Fog. (2005). “Person in fog” [online image]. Retrieved November 14, 2007 from

http://www.flickr.com/photos/t_dawg/67980941/

Good morning (afternoon) everyone. My name is xxx xxxxxx and today I will be talking to you about something that you have most likely seen and experienced at one time or another-- fog. If asked to define fog, most people would probably say that it is an annoying weather occurrence that ties up traffic and creates other travel troubles. While this is true, fog can wreak havoc on the highways and skyways, such a definition really only provides a small piece of the much bigger fog picture. Fog is actually a fascinating weather phenomenon that comes in many different varieties. That is right; there are different types of fog. And believe it or not, fog is not all bad. In fact, it can be quite beneficial.

In order to gain a better understanding of fog, we will take a look at the different types of fog, how and where they typically form, their characteristics, as well as the hazards and benefits associated with them. Before we start exploring the different types of fog that form, though, we need to first understand what fog is. By definition, fog is a cloud, composed of visible water droplets or ice crystals, that forms at the ground, impeding visibility (Ahrens, 2007, p. 110; Wood, 2001, p. 265). In order for the visible water droplets or ice crystals to be considered fog, visibility has to be reduced to less than .62 miles (about 3,000 feet) (Ahrens, 2007, p. 110; Pretor-Pinney, 2006, p. 81). Fog is defined as dense when visibility is reduced to less than a quarter mile (about 1,300 feet) (Ahrens, 2007, p. 110). When visibility is greater than 3,000 feet, visible water droplets in the air are defined as mist (Pretor-Pinney, 2006, p. 81).

In addition to understanding what fog is, it is also important to understand the general principles behind its formation. In order to do this, we must first review the relationship between water vapor and air temperature and pressure. An important component of our air is water vapor, the gaseous form of water (Ahrens, 2007, p. 3). However, exactly how much water vapor is in the air is dependent on the temperature and pressure of that air. That is because air can only contain a certain amount of water vapor at any given temperature and pressure level before it reaches saturation, the maximum level of water vapor it can hold (Ahrens, 2007, p. G-12). The colder the air is, the less water vapor it can hold, meaning that saturation occurs more easily in colder air (Ahrens, 2007, p. 87). So how does all this relate to the formation of fog?

Most fog forms when air is cooled. As we just learned, cold air cannot hold as much water vapor as warm air. Therefore, as air is cooled, it may become saturated because the cooler air cannot maintain the same level of water vapor as it did when it was warmer (Ahrens, 2007, p. 87). As air begins to reach its saturation level, water vapor begins to condense (change to a liquid state) on what are known as condensation nuclei (particles such as dirt, salt and combustion by-product found in the air), forming water droplets (Ahrens, 2007, p. 109-110; Wood, 2001, p. 261). And the closer the air is to saturation, the more condensation that takes places. With fog, so much condensation is occurring that the water droplets become large and highly concentrated (Ahrens, 2007, p. 110). Because of that we can actually see fog. To review, then, most fog forms when air is cooled to the point of saturation, causing water vapor to condense and form large, visible water droplets (Ahrens, 2007, p. 110).

I have deleted most of these notes to keep the file small. Prof. Whitford