Lab 1

LAB 1: Answers to questions

1) B
2) 5
 

Description of the graph: The water in the bucket decreased steadily at a rate of 3 units of water / unit of time.
Description of the draining bucket: The bucket starts with 35 units of water, but loses it through the Leak. The amount of water flowing out of the bucket is regulated by the Leak fraction
. In this case, it is 3 units of water per unit of time. When the model runs, water starts flowing out of the bucket at this rate, until all of it is gone (in almost 12 units of time).

Description of the graph with feedback: The amount of water in the bucket is exponentially sinking. There is a positive feedback here. The feedback made the model behave like the classroom experiment
in my mind.

EXTRA CREDIT: Prediction of the graph with both faucet and leak: The amount of water in the bucket will increase and then stabilize. The same thing happens for different faucet and leak fraction values, although the slope of the curve is altered significantly. For the last question, the amount of water in the bucket is stable after about 20 minutes. After 150 minutes the leak function was changed to 0.9. As a result, half of the amount of water in the bucket was gone. After that the amount was stabilized.
 
 

HOMEWORK:
 

A) A System is:

1 : a regularly interacting or interdependent group of items forming a unified whole <a number system>: as a (1) : a group of interacting bodies under the
influence of related forces <a gravitational system> (2) : an assemblage of substances that is in or tends to equilibrium <a thermodynamic system> b (1) :
a group of body organs that together perform one or more vital functions <the digestive system> (2) : the body considered as a functional unit c : a group
of related natural objects or forces <a river system> d : a group of devices or artificial objects or an organization forming a network especially for
distributing something or serving a common purpose <a telephone system> <a heating system> <a highway system> <a data processing system> e : a
major division of rocks usually larger than a series and including all formed during a period or era f : a form of social, economic, or political organization or
practice <the capitalist system>
2 : an organized set of doctrines, ideas, or principles usually intended to explain the arrangement or working of a systematic whole <the Newtonian system
of mechanics>
3 a : an organized or established procedure <the touch system of typing> b : a manner of classifying, symbolizing, or schematizing <a taxonomic system>
<the decimal system>
4 : harmonious arrangement or pattern : ORDER <bring system out of confusion -- Ellen Glasgow>
 

B) Biosphere:

1 : the part of the world in which life can exist
2 : living beings together with their environment
 

C) Hypothesis:

1 a : an assumption or concession made for the sake of argument b : an interpretation of a practical situation or condition taken as the ground for action
2 : a tentative assumption made in order to draw out and test its logical or empirical consequences
3 : the antecedent clause of a conditional statement
 

D) Geosphere:

The rock portions of the planet: Plates, Crust, Moho, Mantle, and Core.
 

E) Cryosphere:

The frozen regions such as the icecaps, tundra, and moutain glaciers.
 

F) Atmosphere:

The gases which envelope a planet.
 

G) Carbon Cycle:

1 : the cycle of carbon in the earth's ecosystems in which carbon dioxide is fixed by photosynthetic organisms to form organic nutrients and is ultimately
restored to the inorganic state by respiration and protoplasmic decay
2 : a cycle of thermonuclear reactions in which four hydrogen atoms synthesize into a helium atom by the catalytic action of carbon with the release of
nuclear energy and which is held to be the source of most of the energy radiated by the sun and stars.
 

H) Water Cycle:

The sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately
back into the atmosphere as a result of evaporation and transpiration.
 

I) Ozone:

1 : a triatomic very reactive form of oxygen that is a bluish irritating gas of pungent odor, that is formed naturally in the atmosphere by a photochemical
reaction and is a major air pollutant in the lower atmosphere but a beneficial component of the upper atmosphere, and that is used for oxidizing, bleaching,
disinfecting, and deodorizing.
 

J) Radiation Balance:

The balance of the process of emitting radiant energy in the form of waves or particles.
 

K) Albedo:

The reflectivity of a surface. A surface with high albedo (like snow) will reflect more sunlight back into space and absorb less heat.
 

L) Greenhouse Effect:

Certain gases will let solar radiation enter the atmosphere but not leave.  The most common of these are carbon dioxide, methane, and water vapor.
 

M) Feedback:

1 : the return to the input of a part of the output of a machine, system, or process (as for producing changes in an electronic circuit that improve
performance or in an automatic control device that provide self-corrective action)
2 a : the partial reversion of the effects of a process to its source or to a preceding stage b : the transmission of evaluative or corrective information to the
original or controlling source about an action, event, or process; also : the information so transmitted.
 

N) Positive Feedback: Exponential population growth. As the population grows, the population of young people becomes greater. This fuels an even greater -next generation- population of young people and so on.
 

O) Negative Feedback:

Chaotic Oscillations of Tropical Climate: A Dynamic System Theory for ENSO

                                   Bin WANG and Zheng FANG
                 Department of Meteorology, School of Ocean and Earth Science and Technology
                             University of Hawaii at Manoa, Honolulu, Hawaii

                (Manuscript received 17 August 1995, in final form 26 February 1996) ABSTRACT

Based on first principles, a theoretical model for El Niño-Southern Oscillation (ENSO) is derived that consists of prognostic
equations for sea surface temperature (SST) and for thermocline variation. Considering only the largest-scale, equatorially
symmetric, standing basin mode yields a minimum dynamic system that highlights the cyclic, chaotic, and season-dependent
evolution of ENSO.

For a steady annual mean basic state, the dynamic system exhibits a unique limit cycle solution for a fairly restricted range of
air-sea coupling. The limit cycle is a stable attractor and represents an intrinsic interannual oscillation of the coupled system.
The deepening (rising) of the thermocline in the eastern (western) Pacific leads eastern Pacific warming by a small fraction of
the cycle, which agrees well with observation and plays a critical role in sustaining the oscillation. When the nonlinear growth
of SST anomalies reaches a critical amplitude, the delayed response of thermocline adjustment provides a negative feedback,
turning over warming to cooling or vice versa.

When the basic state varies annually, the limit cycle develops a strange attractor and the interannual oscillation displays
inherent deterministic chaos. On the other hand, the transition phase of the oscillation tends to frequently occur in boreal spring
when the basic state is most unstable. The strongest boreal spring instability is due to the weakest mean upwelling and largest
vertical temperature difference across the mixed layer base. The former minimizes the negative feedback of mean upwelling,
whereas the latter maximizes the positive feedback of anomalous upwelling effects on SST; both favor spring instability. It is
argued that the season-dependent coupled instability may be responsible for the tendencies of ENSO phase locking with season
and period-locking to integer multiples of the annual period, which, in turn, create irregularities in oscillation period and
amplitude.
 
 
 
 

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1/27/99
 
 

1) Review of four articles (Nature Vol 396, December 1998)
 

A) "Geoscientists are not just rock stars" : The main point of the article is that there is a need to somehow "quantify the anthropogenic effect on climate and to look at the feedback loop between natural and perturbed systems". Traditional disciplines cannot answer that need, therefore "integrating the study of the bio-, litho-, atmo- and hydrospheres" seems to be the natural response to tackle the tough global problems that humankind faces today. This, of course, won't be easy as a common "language" between scientists of different disciplines must be adopted. In addition, understanding of politics and economics is essential.

B) "Problem solving for the whole Earth": The message of this article is quite similar to the previous one, but here the discipline of "geoscience" is presented as the integration of the traditional disciplines that can meet today's research challenges. It is the duty of the geoscientist to be the one who can understand the "languages" of the traditional disciplines involved and to be the one who will use the gained expertise for the welfare of humanity.

C) "A Risk Proposition": The article examines the career tracks of some geoscientists. They are involved in the university, government and private sectors. Some of the posts held by them are quite unexpected (for example in insurance) but the problems that we face today require interdisciplinary cooperation.

D) "Water and Welfare: Hydrology options": This article focuses on earth's water resources. Particularly water supply and quality issues in the world today are very relevant and pressing. However, water is not distributed equally in the world and this makes these problems more complex. The way to go is the assistance (funding) of countries who have to deal with these problems but lack the necessary resources.
 
 

2) Review of article "Our Health in Flux" (NewScientist, No 116, December 1998)
 

The paper emphasizes the problems that humankind is facing by global change. Stratospheric loss (ozone depletion) and climate change (global warming) are global problems who will affect millions of people. Ozone, which is regarded as a pollutant in the atmosphere but is extremely beneficial in the stratosphere, is thinning because of exposure to manufactured chemicals (CFCs). Therefore the amount of ultraviolet (UV) radiadion we are receiving from the Sun will increase. This will almost certainly lead to an increase in skin and eye cancers, eye cataracts and weakening of the human immune system. On the other hand, climate models suggest that global warming is happening due to an increase of carbon dioxide and other "grenhouse gases" in the atmosphere. The effects on humankind (and particularly in the poorest countries) can be overwhelming as extreme weather, heatwaves, allergic and tropical diseases and a rising sea level can create an apocalyptic world. However, corrective action can be applied but only if global cooperation in the areas of research, economy and politics (which will give rise to a global government?) prevails.
 
 

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2/3/99
 
 

Review of Second Chapter "The nature of Global Environmental Change" (Physical Geography and
Global Environmental Change by O. Slaymaker and T. Spencer)
 

The development of the Earth Sciences as an interdisciplinary field of study has been attributed largely to the global environmental problems that humanity faces today. However, the emergence of the theories
in plate tectonics, the tremendous increase in computing power that stimulated global modeling, the realization of the fragility and of the complexity of the Earth systems as well as the ongoing development of
remote sensing have also played a very important role. We have come to know that technology and population growth gave rise to global environmental change. Earth systems are fragile but we need to
quantify their fragility. Earth Sciences are now called to estimate the extent of global environmental change and offer some course of action. The theoretical background is available, although some assumptions
have to be made. If the correct assumptions are made, and if other modeling problems are removed, then modeling can give an understanding of the extent of the environmental change.
 
 

Lab 2: Answers to the questions

Model "Engineer.STM"
1) The temperature of the house is lower than that of the thermostat setting (the outside temperature is colder than that of the house).
2) The outside temperature is lower than that of the house and this causes heat loss. If the system is off then the two temperatures will eventually become the same. When the system is on the input of heat tries to balance the heat loss.
3) The temperature of the house increases rapidly (system is heating the house).
4) The temperature of the house decreases rapidly (system is cooling the house).
5) 68
6) ... The heating / cooling system is controlled by the thermostat setting. If there is any difference between the temperature of the house and that of the thermostat setting the temperature loss/gain converter is activated and the temperature of the house is adjusted.
7) The difference between the temperature of the house and that of the outside temperature triggers a negative feedback loop.

Model "Econgp.STM"
1) The graph included information about the bison population, the Sioux hunting rate and the commercial hunters. The bison population decreases slowly and then collapses around 1871. This is the period when commercial hunters increase exponentially and the sioux hunting rate collapses.
2) The bison population survives when no commercial hunting is allowed after 1871.
3) The number of commercial hunters increases rapidly in 1871. We could spread the hunters throughout a larger period of time.

Model "Efs.STM"
1) Radiation from the sun reaches the earth, some is scattered to space while a certain amount warms the earth (greenhouse effect).
2) There is a very close correlation between these two variables, the lines in the graph are almost identical.
3) There is very close correlation, however there appears to be a small time gap.
4) Earth_Energy(t) = Earth_Energy(t - dt) + (Solar_To_Earth - Infrared_to_Space) * dt
5) The sun warms, reaches a peak and then cools. The earth's temperature (K) follows the same (but not identical) path.
6) The graph is different know but the pattern is still the same.
7) The sun variable is uphill but the earth temperature variable increases and then levels of.
8) The sun variable is downhill and the earth temperature decreases and levels of.
9) The Earth's albedo must vary but we don't know how.
10) The Earth's albedo is constant until it collapses at about 4.5 million years. This dramatic drop explain the rise in the Earth's temperature.
 

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2/4/99
 
 

Lab 3: Answers to the questions

Activity 2:
1) The comet's water is distributed almost immediately among the reservoirs.
2) Most of it eventually accumulates in the ocean (N5).
3) The hydrologic cycle comes again into equilibrium, the comet's water is now in the ocean.
4) It takes only a few years.
5) No, the results vary quantitatively.
6) Since the volume of a sphere (V) is given by the formula V = [4(pi)r^3] /3  where r is the radius of the sphere, and assuming that the density of the ice is very close to one,
the diameters in question are close to 2.5km, 4.2km and 5.3km respectively.

Activity 3:
7) The distribution of water due to the volcanic erruption is not so quick, in fact it takes about 20 years.
8) It accumulates in the ocean.
9) A new equilibrium state is established in a period of 20 years.
10) The equilibrium here is established in 20 years, while in the second activity the equilibrium is established almost immediately.
11) Yes, the results vary qualitatively. Setting the volcano slider to 10 has no effect to the equilibrium. However, setting it to 50 has a minimal effect.
12) In activity 2 the amount of water stored in the comet accumulates into the ocean. Here there is no net increase in the amount of water, only a transfer from the polar regions to the ocean.
13) Since the volume of a cube (V) is given by the formula V = r^3  where r is the acme of the cube, and assuming constant thickness,
the areas in question are close to 4km^2, 11.5km^2 and 18.2km^2 respectively.

Activity 4:
14) Almost all of the water is found in the oceans and in the polar regions. A small percent is in the geosphere and a even smaller one in the atmosphere.
15) It appears to be that fresh water is available only in the geosphere.

Activity 5:
16) ---1) Donor controlled: Icecap Snowfall, Land Rainfall, Ocean Rainfall, Runoff.
      ---2) Receptor controlled: Evapotranspiration and Ocean Evaporation.
      ---3) Diffusive: Atmospheric transport, Percolation, Melting.
17) Since the flow is diffusive, the amount of water vapor in marine atmosphere must be less than that of the terrestrial atmosphere.
18) It comes from Surface Water which originates either from the Terrestrial Atmosphere or from Melting.
19) Ground water can become surface water and the opposite is true.
20) Percolation is the process in question.

Activity 6:
21) The path is: Ocean - (Ocean Evaporation) - Marine Atmosphere - (Ocean Rainfall) - Ocean.
22) The common path is Ocean - (Ocean Evaporation) - Marine Atmosphere. Then the molecule goes all the way until the Ground Water.

Activity 7:
23)
24)

Activity 8:
25) The cycle is "open" in the second activity and it is "closed" in the third one.

Activity 9:
26) The cycle is stable to pertubations as described in the activities. Sometimes the cycle is stabilized after a considerable amount of time (eg 20 years or more).
 

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