Week of November 10

this week we worked on the questions given to us in class, my group was unable to finish them in class and I took them home to finish over the weekend. This is what I did (there were picture but I cant figure out how to post them):

Discuss the following concepts: albedo, emissivity, evapotranspiration and energy balance.
Albedo- surface reflectivity of sun's radiation. Represented by a number between 0 and 1 or a percentage. An ideal white body has an albedo of 100% and an ideal black body of 0%. On average the earth has an albedo of about 4% and the atmosphere has about 26%.Interestingly, fresh snow has an albedo of about 95%. What that means for earth is that about 30% of the radiation of the sun is reflected by the atmosphere. As well, it explains why any change in albedo will change the overall energy flow, which will therefore change the way the earth's climate acts. So if either the earth's or the atmosphere's albedo is reduced by about one percent, say from the melting of the ice caps, which are a large source of reflection, the whole energy balance is thrown off, and the earth will have to deal with more radiation coming in, which means more absorption and emission from the surface, which means more spray from the atmosphere back down, which means an increase in temperature.
Emissivity- the efficiency with which an object emits electromagnetic waves. This efficiency equals the ability of that same planet to absorb the given wavelength. Efficiency is inverse to reflectivity. Represented by a number between 0 and 1, 1 being the most emmisive. Emissivity is important, as it shows that the actual surface of the earth holds very little of the infrared radiation that passes through the atmosphere. That then plays into the above situation, where the atmosphere isn't quite as emissive, and a sort of convection occurs further heating the lower atmosphere. Now, if the emissivity of the earth surface is decreased, it would create a situation where more of the infrared radiation is just outright reflected instead of absorbed and remitted and then convected, which means that lower atmospheric temperatures would generally lower.
Evapotranspiration- describes the transport of water into the atmosphere from surfaces, including the soil and from vegetation. What canopy surfaces and vegetation covered water surface wetlands also contribute to evapotranspiration. The major role of evapotranspiration is the movement of excess heat energy in the lower atmosphere into the higher atmosphere where it is lost, and the moisture condenses to create cloud cover, which has its own effects on global warming.
Energy Balance- when the energy entering a system equals the energy leaving it. As is right now, Earth is not in a state of perfect energy balance, as more of the radiation stays then leaves, which creates a state of convection, heating the lower atmosphere and cooling the upper atmosphere, thereby heightening the greenhouse effect. Now if the earth was in a complete energy equilibrium or balance, the climates as were would be much more stable, although it would all still vary with the seasons.

Explain the nature of and difference between two box, two-dimensional and three-dimensional climate models
Two box- shows two boxes, one representing the atmosphere and one representing the surface of the earth. The model has arrows, each numbered and representing a specific equation, to show the energy exchanges between the earth, the atmosphere, the sun and space. Equations for the temperature of the surface of the earth and the atmosphere can then be derived by solving the equations represented by the arrows. The two box model is a type of equilibrium model in that values are assigned to the various energy flows and the model is used to calculate temperature values. This model only tells what the temperature would be if the climate system was in equilibrium, and cannot account for green house gases that have varying concentrations over time.
Two Dimensional- accounts for different latitudes and altitudes. These models can be used to simulate seasonal changes, and atmospheric circulations that transfer energy. In order to account for atmospheric circulations that transfer energy the model needs to take into account the flow of air and its moisture. This moisture caries latent energy and results in cloud formation and precipitation. Other factors that, if taken into account, would make this model more accurate include the movement of green house gases. In order to create this model momentum and the affect one designated block of air has on its neighbors through momentum must be taken into account as well as the frictional forces the ground exerts on the air. A two-dimensional model is know a type of time-dependent model in that it considers the flow of energy and matter and can predict and project how the system would be affected by changing model conditions and over time. These models are used by scientists to experiment with specific scenarios and predict how they would affect the Earth's climate.
Three- Dimensional- “have it all.” Can account for land and water surfaces, for elements that cover surfaces and affect albedo such as ice and vegetation coverage, for the configuration of continents, the transfer of moisture and atmospheric circulation in every direction. GCMs, aka global climate models, previously known as general circulation models are models that include atmosphere circulation. The three-dimensional climate model is also a type of more sophisticated time-dependent model.

The more advanced models become the better scientists are able to predict changes in climate over time. The original climate models, one dimensional and two dimensional models could only account for the flows of matter and energy north and south and seasonal changes in climate. The most advanced climate models, such as three dimensional time-dependent models cut the earth and its atmosphere up into many individual boxes. This model can then simulate the flow of energy and matter within the boxes and between various boxes. Furthermore, this model can predict and solve the way boxes and their matter and energy will interact over and over again to project into the future and allow for changes in model conditions. These most advanced models allow scientists to tell what will happen if greenhouse gasses continue to be emitted into the atmosphere, and enable the projections of what will happen to the planet (such as the melting of ice at the pole and the rising of sea levels) and at what time, relative to one another.

In what sense is radiation the only heat-transfer process affection the planet’s energy balance, in what sense do other processes play a role?
Radiation is the only heat-transfer process because all energy that is absorbed by or projected towards the earth does so in the form of energy. Solar radiation and infrared radiation from greenhouse gasses are pretty much the only energy that has the potential to be absorbed by the earth’s surface and affect the energy balance. Therefore without energy in the form of radiation there would be no energy. However radiation is not the way energy is lost from the system. Convection (when heated surface air takes energy with it) and evapotranspiration (described above) are other ways energy is lost. Therefore, radiation is necessary for an energy balance, but not the whole picture. It is important to understand what affects the energy balance of the earth because the extra energy that has recently been accumulating and throwing off the energy balance is causing the earths ocean temperatures and levels to rise. Global warming is seen in the lack of energy balance of the earth and therefore it is necessary to understand what affects this energy balance, and it isn’t all about radiation as some sources would make it seem, there are other natural processes at work.


I think these questions were interesting and straight foward, however, the grading system was a little unfair. If the group did not include diagrams they could not recieve a high grade, even if they did an excellent job of explaining their answers. I don't think it graded the assignement as you intended or put the emphasis on what you consider most important, however I could be wrong. I do think that if the students are given a grading rubric before doing an assignment, and the rubric is simple and clear, and then the students don't follow the rubric (don't include pictures for example) then they did not follow directions. Following directions is a simple life skill we all must learn, and if a teacher gives directions and the students do not follow them, it is the student's fault. Yet, if rubrics are going to become a part of the class, and you are going to take them very seriously (aka no picture means a 3/5) make sure the students know how seriously you intend to take the grading system, so when they recieve their first poor grade they understand why. Honors students tend to think they can just ignore rubrics because their quality of work always recieved a high grade, but if the rubrics are specific this is a recipe of disaster...make sure the students know what they are getting into. Other wise I like the rubrics, I feel like I have a better understanding of what quality of work you expect of me and what you mean when you say "answer these questions." I suggest using them in the future.