SPRING 1999
March 8, 1999 ---- Mr. Mike Mogil
Weather and Air Pollution; Climatology of Pollution
SPRING 1999
March 8, 1999 ---- Mr. Mike Mogil
Weather and Air Pollution; Climatology of Pollution
-feet, hands, extremities, (all of this is especially visible when the air conditioner is on.) Possible reasons for this? Heat rises, so above ground is warmer than the floor.
Radiosonde
Radiosonde-the first word "radio" relates to how the info translated back to earth, "sonde" meaning sounding. We sent up radiosondes from earth to get info on moisture, temperature and wind speed.
The following table is an example of a radiosonde.
Radiosonde
A
radiosonde is constructed in a special kind of graph that is skew-T-log-P. The significance of this is that the lines in the graph are skewed, and the vertical lines in the graph representing pressure are logarithmic, (log-P).
Coding for Wind Speed
The model of a dot with a stick indicates the direction the wind is going in. The example below illustrates that the wind is going in the following direction. The following table is the coding used to illustrate the velocity of wind.
Dewpoint
When warmer air is cooled to a certain temperature and moisture forms, the moisture is referred to as dew and the point at which it forms is referred to as the dew point. Therefore, the dewpoint is the temperature at which warm air, cools and condenses, forming visible moisture.
The closer the current temperature is to the dewpoint, the more moist the air will be. The further apart the dew point temperature is from the current temperature, the drier the air is.
As air rises and sinks its pressure changes and so does its temperature. This is referred to as a lapse rate. On average, dry air at one level, will be 5.4 degrees F colder 1,000 feet above that point. The reverse is true for air that falls 1,000 feet. (5.4 degrees F warmer).
However, we find that if there is moisture in the air (wet) and condensation takes place, reaching the dewpoint, the air will only cool 3.5 degrees F/1,000ft, due to the presence of latent heat in the water.
Note: There is no warming of 3.5 degrees F when air falls. Evaporation is occurring and clouds are disappearing continuously.
Example # 1
We start on the side of the mountain that borders the San Francisco ocean. The winds are coming across the land and must rise and climb over the Sierra Nevada mountains. What effects does the change in altitude have on the dew point and temperature?
A couple things to remember:
1. The actual current temperature can never be lower than the dew point. If the dew point is reached and the current temperature goes down, than the dew point goes down as well.
2. Once the dew point is reached, the decrease in temperature is now 3.5 degrees F versus 5.4 degrees F.
3. As the air rises over the mountains moisture forms and precipitation occurs first, as rain and as it gets colder, snow. On the other side of the mountain the air will be dry due to the loss of precipitation and the weather will most likely be warmer and mild.
The dew point is held somewhat constant die to excess removal of water as air climbed the mountain. Once over the mountain the air is drier and falls and starts to warm up again.
This entire process is referred to as a Rain Shadow
Inversions When temperature is warmer above and colder below this is referred to as an inversion. Cooler air can become trapped below warmer air in the atmosphere. The warm air acts like a lid on a boiling pot not allowing the air to mover vertically so that it gets trapped. This is a concern when we think of pollution. On the ground below are cars, smokestacks, and factories. These all contribute to our air pollution. If this air is not released, the pollutants can concentrate at high numbers in a given area which can be very harmful. These factors must be considered. This is a problem in places like Los Angeles.
Vulcanism
Where are the local volcanoes today? New Jersey, Maryland, and Virginia. Of course these aren’t active volcanoes anymore but they once were back in our geological history.
Where are the active volcanoes? Worldwide is the simple answer. This is an issue that will be addressed in today’s lecture but as example we’ve all most likely heard of the Ring of Fire. It’s a ring of volcanoes that are active and surround the perimeter of the Pacific Ocean. Later we will see how the Ring of Fire was formed and why its name fit it so properly.
Before we can go any further we must have an understanding of what the difference between meteorology and climatology.
For our interests we are primarily concerned with volcanoes that when they erupt, shooting ash and other debris into the atmosphere. Lava flowing volcanoes do not produce a change in global climate, so we are not interested in studying these types of volcanoes in this lecture, but they are very interesting when trying to understand the geological makeup of the earth. In regards to the ash-erupting volcanoes one can imagine the profound cooling effect these volcanoes have on temperature. Following an eruption, clouds of ash filling the stratosphere have the ability to block out solar energy from the sun. Worst case scenario, no sunlight gets through and photosynthesis is blocked and the food chain comes to a complete halt. Many scientists think the previous statement could have been the cause for the end of dinosaur age.
Let’s take a look at an example of vulcanism:
June 1991, Mount Pinatubo in the Philippine islands erupted. What makes this eruption unique is that this volcano was thoroughly investigated before the eruption ever occurred. The United States had a defense program in the Philippines and decided it would be highly advantageous for them to know when the volcano was going to erupt so that they evacuate its troops, supplies, etc. The result of this research was piles of data that possibly could be used in future attempts at predicting volcanic eruptions, or even more importantly assessing the effects of an eruption on climate. The study of Mount Pinatubu was so extensive that PBS ran a series on the volcano.
Ash orbiting the stratosphere that came from the explosion of Mt. Pinatubu controlled the temperature and weather of the earth for two years. Natives of Washington, D.C. who are accustomed to hot and humid temperatures during most summers received an unusually pleasant summer in 1992. NASA watched the ash encircle the latitudinal belts initially before the ash diffused longitudinally using remote sensing imagery from its satellites. If a volcano of the size of Mt. Pinatubu could control the weather of the earth for two years one can imagine what a volcano of a larger size will do to the climate if it erupts or if multiple volcanoes erupt close to the same time. Blocking the sun with ash will change the climate. In addition to the change in climate there would be an increase of pollutants in the atmosphere from the release of volcanic gas. Volcanic gas includes H2S, CO2, HCl, and HF, all of which are pollutants to the environment at high enough concentrations.
Here’s a list of the top volcanic eruptions in order of strongest to weakest:
In the past year there have been 23 eruptions but their effect on the climate of the earth was negligible.
In 1980 Mt. St. Helens erupted and this was the first time ash flow had been documented on multi media. Satellites and special planes were used to track the path of the ash as it orbited the earth. Three days after the eruption of Mt. St. Helens in Washington state the ash landed in Washington, D.C. As an offshoot of this volcanic eruption in 1981 Washington state had its best harvest for apples ever.
What is magma? It is molten material/rock of inner earth with a temperature of 20000F.
There are two types of volcanoes, strato and composite, or respectively lava-flowing and ash erupting. The location of these types of depends on the following:
Plate Tectonic Theory:
The earth is divided into at least 33 separate plates. The continents and oceans overlay these plates. Plate movement is driven by tectonics, which is energy from within the earth derived from earthquakes, faults and vulcanism. The plates themselves vary in size from small to medium to large. Many of the plates are named after the discoverer such as the Juan de Fuca plate. This plate contains the Cascade volcanoes (Mt. St. Helens and Mt. Rainier). In fact some of our proof for volcanic eruptions of Mt. St. Helens comes from Native American oral history.
Ring Of Fire
Archipelagoes
Subduction Zone
Rifts
Hot Spots
Examples of Vulcanism:
One way scientists are able to determine when volcanic events have occurred is from evidence of huge sulfur deposits. Power plants love the fact that volcanoes erupt large scale levels of sulfur into the atmosphere because they mask their own pollution in the atmosphere.
Sulfur does have its advantages such as a large class of sulfur drugs that have an enormous range of benefits for certain ailments.
Every 50 or so years there is at least one volcanic eruption that controls the climate of the earth. The makeup of the interior of the earth may do more to change the climate of the earth than any number of humans could do with their technology. At the same time why seal our own fate with needless pollution.
Web Sites To Visit:
http://volcanoes.usgs.gov
Some of you out there might think of the television series Star Trek or one of it’s characters, Spock, when you hear the word vulcanism but what it really refers to is the study of volcanoes and how they relate to global changes in geology, weather, and climatology.
Meteorology is the study of current weather conditions, which relies on the disciplines of earth science and physics.
Climatology is primarily concerned with past weather conditions.1.) 5000 BC Mt. Mazama
2.) 1815 AD Tamboro, Indonesia
3.) 1883 AD Krakatoa, Indonesia - -- entire island went into the atmosphere
during the summer of this volcanic eruption it
snowed all summer in New England
4.) 1912 AD Mt. Katmal, Alaska --- craters from this eruption are 1-3 km in diameter
5.) 1991 AD Mt. Pinatubu, Philippines --- caldera is up to 30km
6.) 1900 AD Mt. St. Helens, Washington
7.) 79 AD Vesuvius (Herculanium), Italy
8.) 1707 AD Fuji, Japan
9.) 1956 AD Bezymianny, Kamachaika, USSR
10.) 1842-57 AD Mt. St. Helens
11.) 1586 AD Kelut, Indonesia
The term Ring of Fire is used to refer to a string of active volcanoes that encircle the Pacific Ocean. If one were looking at a map of the Pacific plate the edges of this plate would like teeth. These teeth represent where the Pacific plate comes into contact with another plate. When two plates collide there is the possibility that one of the plates will go under the other, which is the case of the Pacific plate. The plate that is pushed under another will go deep into the earth’s crust where it comes into contact with magma. The temperature of this magma will heat the edge of the plate and convert it into magma. This is literally the best recycling system on our planet. If this magma reaches the surface it will cool and harden into several types of rocks (granite ["grain-like"]; chyolite; and andesite ["igneous in Andes"]). Along the ridge of the plate there are rich volcanic rock formations.
An archipelago refers to a chain of volcanic islands such as the Caribbean islands or the Aleutian islands of Alaska.
A subduction zone occurs when two plates collide and one of the plates is forced upward to create a chain of volcanoes and the other plate goes underneath the other. The end result is a chain of volcanoes that are aligned with boundary of the two collided plates. It is also important to note that most volcanoes are submarine.
If a condition occurs where two plates collide there must be a place where plates are moving apart and this latter condition is referred to as a rift. At the location of the rift it is possible for molten magma to surface.
Keeping in mind that tectonic plates are in constant motion there are rare situations where hot magma burns through the mantle of the earth to produce volcanoes. The location of where magma burns through a plate is called a hot spot. The Hawaiian islands are a good example of where a hot spot has occurred. In the case of hot spots only the last island is active. An analogy to help you visualize this would be a situation where a match is burning underneath a sheet of paper and burns a hole in the sheet. Now as you move that piece of paper you will create a new hole and so on. Only the last hole has the match under it and we can akin this to a hot spot. Hot spots are not associated with global change but interesting nonetheless.
http://www.dartmouth.edu/~volcano/
http://skye.gsfc.nasa.gov/eruptions/pinatubo/pinash.html
http://volcano.und.nodak.edu/vw.html
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