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QUESTION 1. This discussion question is found in Lectures 11a on the Hydrologic Cycle. Refer to the whole lecture (parts a and b, as well as any other lectures or sources you choose) for information, but the specifics for the discussion question are on slides 9-11. You may also want to refer back to Lecture 2 on constructing system diagrams if you need a refresher.This may be on a PowerPoint slide, Word document, or jpeg file. Important: Submit your responses to the in the Module titled ‘Discussion Assignments UPLOAD’. You will see a DQ #6 entry. Upload your diagram there. YOU COULD USE LECTURE 11.a,b. HYDROLOGICAL CYCLE TO ANSWER THIS SHORT QUESTION. QUESTION; Upload your PowerPoint slide or Word document for Discussion Question 6 here. You should use ALL of the reservoirs, transfer processes, and variables provided, and feel free to add your own. Transfer processes and variables may be used more than once in your systems diagram. Be sure to use arrows to indicate direction of flow.
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Lecture introducing the hydrologic cycle.
– Introduction to H2O as a substance.
– Reservoirs of H2O on Earth.
– Processes that move or transform H2O.
– Hydrologic cycle exercise.
– Fluxes in the hydrologic cycle (the time element).
– Water as a catalyst – the significance of H2O.
Water in motion.
Organization of lectures for the hydrologic
cycle part of the course.
Remember that a large part of the course is organized around the
hydrologic, rock and carbon cycles. The outline below should help
you put this lecture on the hydrologic cycle in a larger context.
– Introduction to the hydrologic cycle.
– Weather systems.
– Climate.
– Oceanic circulation and dynamics.
– Terrestrial surface water.
– Groundwater systems and resources.
– Glacial dynamics.
Some important properties of di-hydrogen monoxide –
H2O.
– It is present on Earth as ice, water, and water vapor.
– The water molecule is asymmetric, which gives it many of its peculiar
properties.
– Water acts as a solvent, and is commonly referred to as the universal
solvent, meaning it can contain ions. You may think of this as the saltiness
of water.
– The solid ice phase is less dense than liquid water, and hence floats.
– Water has a large liquid range, from 0 to 100 degrees Celsius at
atmospheric pressures.
– Water has a low viscosity, a high ability to flow.
-The unit of heat known as a calorie is the amount it takes to raise 1 gram
of water from 14.5 to 15.5 degrees Celsius.
– Energy is either absorbed or given off when water changes phases (e.g.
from ice to water).
Study suggestion: Perhaps underline the important attributes above.
For a good description of the asymmetric
character of water and its significance https://en.wikipedia.org/wiki/Properties_of_water
-For a bit of humor:
http://www.dhmo.org/
How would the Earth be different if ice did not float?
Temperature
(degrees Celsius)
0 (solid)
0 (liquid)
4
20
40
60
80
100 (gas)
Density
of H2O
(grams per cubic centimeter)
0.9150
0.9999
1.0000
0.9982
0.9922
0.9832
0.9718
0.0006
In this remarkable NOAA satellite
image we can see numerous reservoirs
in the hydrologic cycle, from ocean
waters, to clouds to glacial ice and some
big icebergs. If ice sank, these glaciers
would simply slide underneath the
ocean waters to the depths. Source:
http://www.osei.noaa.gov/Events/Ice/20
04/ICEantarc349_N6L.jpg
Pressure –>
Phase diagram for pure water, a one component system. Since the
atmosphere includes water vapor, air is a multi-component system, and its
behavior is more complex than displayed here. The important point here is
that maps that describe the state (solid, liquid or gaseous) of a system in
different conditions can be made.
Phase diagram modified from http://wine1.sb.fsu.edu/chm1045/notes/Forces/Phase/h2ophase.gif
Phase transformation energy
As heat energy is added to ice its temperature increases until it
reaches 0 degrees Celsius (32 degrees Fahrenheit), at which point
more energy must be added (without a temperature change)
before it melts. In fact, for 1 gram of ice 79.7 calories of heat must
be added. This is known as the latent heat of fusion. Ice and
water can both be at 32 degrees, but the water holds more heat
energy. Similarly there is a latent heat of vaporization required to
change water into water vapor (to evaporate). For the range of
temperature from 0 to 40 degrees Celsius, the latent heat of
vaporization, in units of calories per gram of water, is Hv = 597.3 0.564T. When water condenses, an equivalent latent heat of
condensation is released, since the water is at a lower energy
state than the vapor.
Why is this so important to Earth system and hydrologic cycle dynamics?
Perhaps try to answer this yourself before listening to the answer.
Hint: How much energy was released in condensation of a
cubic inch of rainfall?
What are reservoirs of H2O on Earth
(where is the water)?
Water source
Water volume, in
cubic miles
Percent of total water
Oceans
317,000,000
97.24%
Icecaps, Glaciers
7,000,000
2.14%
Ground water
2,000,000
0.61%
Fresh-water lakes
30,000
0.009%
Inland seas
25,000
0.008%
Soil moisture
16,000
0.005%
Atmosphere
3,100
0.001%
Rivers
300
0.0001%
Total water volume
326,000,000
100%
Source: Nace, U.S. Geological Survey, 1967
Other possible reservoirs:
– Biosphere.
– In hydrated minerals such as clays.
-In permafrost (perhaps part of the groundwater reservoir estimate above).
While these reservoirs are not large in volume they are important in other ways.
What are the processes that move or transform H2O from one
reservoir to another?
H2O transformation processes:
– Involving energy gain: melting, evaporation, sublimation.
– Involving energy loss: freezing, condensation, deposition.
-Hydration reactions and dehydration reactions.
Weathering of feldspar plus water produces kaolinite, a clay with a
chemical formula of Al2Si2O5(OH)4. This is a hydration reaction. The OH
part of the mineral comes from the water, and, at high pressures and
temperatures, the mineral can break down and release water in a dehydration
reaction.
Earth system processes that move H2O:
– Atmospheric circulation.
– Oceanic circulation.
– Glacial ice movement.
– Surface runoff.
– Seepage through porous sediment and rock.
– Groundwater flow and hydrothermal circulation through the geosphere.
– Subduction into Earth’s interior of plate material with hydrated minerals (e.g. clay).
Hydrologic cycle exercise.
Instructions: On the next page are 3 columns of items, one of reservoirs in boxes, one of
processes that transfer water from one reservoir to another in diamonds, and one of
variables that influence those transfer processes in ovals. You should assemble
them into your own version of the hydrologic cycle, spending about an hour on your
effort. You are free to add additional items, or use an item more than once. This
should be submitted through the Assignment provided on Canvas as a PowerPoint
document (see below). This will count toward the Discussion portion of your grade.
Every diagram constructed will differ slightly in its specific arrangement, but
experience indicates strong similarities will exist among efforts. An example of the
beginning of such a diagram follows two slides from this one. Remember to revisit
earlier lecture materials about how to construct system diagrams.
To complete this:
In the composer format of PowerPoint, go to the slide with the 3 columns of items, copy
all the items on that page, open up a new PowerPoint document, paste these items on a
new page, rearrange them into your version of the hydrologic cycle adding arrows and
using the line tool to connect the various elements, save your final product using your last
name as the file name, and submit the document to the designated assignment in
Canvas.
Some components of your hydrologic cycle diagram.
Oceanic water
Atmospheric
moisture
Surface water
(terrestrial)
condensation
to snow
groundH2O
discharge to
spring
Chemical
weathering
Root
uptake
atmospheric
pressure
temperature
evaporation
Ground water
topography
freezing
Glaciers
Plants
melting
condensation
to rain
humidity
temperature
seepage
Hydrated
minerals
runoff
sediment
porosity
Example of beginning core of a hydrologic cycle
system diagram.
Atmospheric
moisture
temperature
evaporation
Surface water
(terrestrial)
Remember to use arrows to indicate the direction of flow.
Please proceed to part b of this lecture.
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