Paragraph 1: What is the connection between altitude, microclimate, and vegetation in and around the Grand Canyon?  Please give examples from the lab, and you can also include your own observations.

Paragraph 2: What is the connection between the direction a slope faces (aspect), microclimate, and vegetation in and around the Grand Canyon? Please give examples from the lab, and you can also include your own observations.

Paragraph 3: Was there anything in particular that struck you as particularly interesting about the connection between topography, microclimates, and vegetation?  Please do not simply write down a sentence.  Explain your idea, and elaborate with at least a few sentences.

Paragraph 4: Please provide you thoughts on this geovisualization as a tool to investigate connections between microclimate and the biomass (abundance) of vegetation. Please do not simply write down a sentence.  Explain your idea, and elaborate with at least a few sentences.

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Lab Title Microclimates and their link to
vegetation in the Grand Canyon

Courtesy of the National Park Service (NPS), a helicopter view of mixed
Ponderosa Pine – Oak forest on the rim transitioning toward desert scrub
vegetation near the bottom of the Grand Canyon.

What is
this lab all
about?

Arizona is the “Grand Canyon State.” From the perspective of climate
and its associated biota, this is especially true. The full range of Arizona’s
climates and ecoregions is on display. The highest elevations on the
Kaibab Plateau’s north rim host spruce-fir-aspen forest, while Mojave and
Sonoran desert plants pepper its lowest elevations. This lab tasks you
with analyzing how the Grand Canyon’s topography influences its climate
and vegetation patterns. The goal is for you to better understand basic
concepts of physical geography science by interrogating the sorts of data
used in scientific research – but all in a 100-level class (no prerequisites).

Lab Worth The points you accumulate for correct answers count towards your grade.
Incorrect answers do not hurt your grade.

2

Computer
program
used in
this lab

You will be given instructions in a canvas module page on how to
download virtual world of Grand Canyon microclimatology and
vegetation. In this program, you are a virtual character able to wander
around the Grand Canyon’s landscape, summer temperatures, winter
temperatures, and vegetation.

WARNING: There are two different Grand Canyon geovisualizations –
this one and one focusing on the topography and its connection to rock
types. They are different video games with different data. You must use
the microclimate game to complete this lab.

Interesting
maps to
download
– not
necessary
to do the
labs, but
helpful to
some
students

National Park Service map of Grand Canyon National Park:
https://www.nps.gov/carto/hfc/carto/media/GRCAmap1

NPS 3D map of the Grand Canyon
https://www.nps.gov/carto/hfc/carto/media/GRCA3DMap

Shaded relief map of the Grand Canyon area:
https://legacy.lib.utexas.edu/maps/national_parks/grand_canyon_map

Vegetation Map of the Grand Canyon (23.4 MB)
https://irma.nps.gov/DataStore/Reference/Profile/2221240

SQ
general
studies
criteria

Students analyze geographical data using the scientific method, keeping
in mind scientific uncertainty. Students also use mathematics in analyzing
physical geography processes and patterns.

TABLE OF CONTENTS OF THIS DOCUMENT

1. Preface: How do you begin to understand the complexity of microclimate
and its role on vegetation?

Page

3

2. Overview of lab activities Page

5

Stage A: Lecture Basics on Grand Canyon ecoregions and microclimate

Page

7

Stage B: Exploration: Making observations related to climate and
biogeography of the Grand Canyon

Page

14

Stage C: More detailed investigation of microclimate and vegetation

Page

24

Stage D: Synthesis

Page

37

3

1. Preface: How do you begin to understand the complexity of microclimate and its
role on vegetation?

The Grand Canyon is famous for many reasons, primarily its stunning landscape. Part of
that landscape involves diverse ecoregions. The diagram below is famous for portraying this
diversity, and it was redrawn by the National Park Service (with the elevations higher than the
dashed-line Grand Canyon found in the nearby San Francisco Peaks).
The idea conveyed so cleanly and so neatly in this diagram is that higher locations are
cooler and wetter, with north-facing slopes being protected from solar radiation more than south-
facing slopes. This one diagram does a nice of idea of communicating the basic idea of
microclimate influencing these ecoregions (sometimes called life zones).

When the National Park Service tried to create a more realistic mapping of plant types in
the Grand Canyon, a very complicated map was produced: Vegetation Map of the Grand Canyon
(23.4 MB) https://irma.nps.gov/DataStore/Reference/Profile/2221240 . In this map below, you
can see a bewildering complexity of plant associations displayed by different colors. In all, there
are over 30 groups presented. This map is a generalization of reality found in the field. It is a
product of a mixture of a lot of fieldwork and study of remotely sensed imagery.

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These plant associations are intimately connected with climate, and the climograph below
summarizes the sort of decadal conditions that promote a Ponderosa Pine forest (tan color in the
above map) on the rims of the Grand Canyon: cool winters, and both winter (snow) and summer
(thunderstorm) peaks in precipitation.

Even in the same sort of Ponderosa Pine forest, there are differences. On the North Rim of the
Grand Canyon the Ponderosa Pine is mixed with some fir and other sorts of cool-loving plants
that require more precipitation. On the South Rim, the Ponderosa Pine tends to be mixed with
oak and needs less precipitation and can tolerate warmer temperatures.

These sorts of plots are also called climographs, and they portray both temperature and

precipitation information throughout the year. Note the warmer summer highs on the South Rim
and the higher January-March precipitation (as snow) bars on the North Rim.

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Before this lab, flat maps and climographs formed the basis of student learning of this
material. Everything was generalized for the student. The vegetation maps and diagrams are
either extremely complicated or too general, and both are frustrating for introductory students.
That is why we turned to video game technology and geovisualization of climate and
plants in and around the Grand Canyon. You can explore these relationships, and our job as
laboratory builders is to try to do justice to the change in educational technology. I hope you
think we did an okay job with this lab.

2. Overview of Laboratory Activities

You are undoubtedly familiar with the key scientific concepts that this lab covers, based
on your life experiences (see the left column). The different stages of this laboratory delve deeper
into these experiences by linking them to core aspects of physical geography.

Life Experience
of Students

Stage A – Videogame
exploration

Stage B- presentation of academic
concepts (lecture, reading, or both)
that are a review of GPH 111

• the sun rises in the
east, reaching its
highest point at noon,
and sets in the west

Surface temperatures are
acquired at 10am and can
be interpreted from life
experience.

Understanding diurnal temperature
variations are a core concept in
physical geography

• in the coterminous
USA, the sun is always
in the south part of the
sky

North-facing slopes
receive less solar radiation
and tend to be cooler than
south-facing slopes

Seasonal temperature fluctuations
and seasonal radiation balances are
greatly influenced by the location of
the sun and how it varies annually.

• wintertime sun angles
are much lower than
summertime sun angles

The steepest slopes facing
north might not receive
any (or very little) winter
insolation

Noon sun angle calculations help
explain local radiation balances

• precipitation (both
rain and snow)
increases with higher
elevations

More precipitation helps
increase biomass (more
plant material) and
influences type of plants

The bimodal precipitation of winter
high elevation snows and summer
thunderstorms is vital to explaining
Grand Canyon biogeography

• temperature decreases
with higher elevations

Hotter temperatures help
decrease biomass and
promote more xeric (dry-
loving) plants

Lower temperatures reduce
evapotranspiration stresses on plants,
while higher temperatures limit
plants severely

Different life zones
exist, such as deserts,
rainforests, conifer
forests, and others.

Ecoregions consist of
different assemblages of
plants that combine
together to produce a
biomass signal recorded
by satellites.

By taking ratios of different parts of
the electromagnetic spectrum, its
possible to calculate a NDVI
(normalized difference vegetation
index) that can be used to interpret
plant types

The “rules” governing SQ laboratory science courses indicate that students practice the
scientific process of gathering and interpreting data, given the prior understanding of a field of
study (Stage B). The lecture in Stage B (or reading material; they are the same) reinforces and
elaborates on basic concepts from GPH 111, but in the context of the Grand Canyon:

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• Diurnal (temperature) variation is driven by solar radiation that peaks at noon, but there
is a lag when the warmest temperatures are felt (mid-afternoon). Thus, there is a radiation balance
of incoming solar radiation and outgoing terrestrial radiation with a diurnal cycle
• There are also annual changes in the radiation balance, driven mostly by seasonal
changes in the amount of solar radiation. This is heavily influenced by the angle of the sun.
• Lapse rates are another way of saying how temperature changes with elevation (both on
the ground, and up into the atmosphere).
• Precipitation varies seasonally, and in the case of the Grand Canyon, there exists a
winter-time peak with snow at higher elevations and a summer-time peak with thunderstorms
during Arizona’s monsoon season.
• All of the above creates a complex fabric of daily, seasonal, and annual changes in
temperature and precipitation that influences the amount of biomass (all plant and animal
material) and the type of plants/animals living at different locations.

The hope is that by gathering and interpreting these sorts of data in Stage C, the science becomes
more powerful and enjoyable for you. Then, you are challenged (without any grade penalty) to
synthesize ideas for yourself (and also earn additional points) by writing a 4 paragraph essay in
Stage D.

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STAGE A: Lecture (or read the same content below) about
microclimates and vegetation.

Link to video lecture:

The idea of this section is to provide you basic background information about the

interrelationships between microclimate the weather. The content in this PDF file is the same as
the content in the lecture that is linked through the Canvas page for the Stage A part of this lab.
There is a quiz on the information that you are welcome to take that is administered in canvas.
Points from this quiz will be added to your GPH 112 point total. However, there’s no penalty for
incorrect answers or not taking the quiz

Introduction
Several different climates exist around and within the canyon, a result of a vertical mile of
elevation change from rim to river. Temperatures at the bottom of the canyon soar regularly over
100F while the North Rim sometimes sees temperatures below 0F. Over 11 feet of snow closes
the North Rim every winter while the bottom of the canyon sees only 8 inches of rain annually.
Locations around the Grand Canyon also have localized microclimate variations. Small changes
in solar radiation, cast by shadows from the canyon walls, can have a noticeable influence on
temperature within the small regions of the canyon. In this lab, we’ll look closer at what
influences the microclimates of the Grand Canyon and how that impacts plants and animals
within its walls.

Atmosphere and Lapse Rates
If you’ve ever been on top of a large mountain or at a significant elevation and felt that it was
harder to breath, you’ve noticed that higher altitudes have lower air pressure, and as a result lower
oxygen for you to breath. This is because the further away from the center of the earth you are,
the less gravity pulls on you and as a result, pulls on the air molecules. This leads to the
atmosphere being thinner, with most of the air down closer to the surface. As a result, the air
pressure is at higher altitudes. Lower air pressure means temperature also decreases. Generally, in
the free atmosphere, for every kilometer ascended into the atmosphere it is 6.5C cooler
(3.5F/1000feet). This is called the normal, or environmental lapse rate.

However, because of the complex topography and surface heating within the Grand Canyon, this
air temperature lapse rate is generally greater than the environmental lapse rate, particularly in the
summer where the lapse rate can approach 7.5C per kilometer. (5.5oF per 1000 feet). We will call
this lapse rate the near-surface lapse rate because of the influence surface variables (reflectivity,
moisture, heat release/absorption, etc). This lapse rate changes seasonally; in the winter, the
surface lapse rate can drop below 3C/km. This winter change is a result of multiple factors. Since
cool air is denser, it sinks off the top of the rim into the canyon below, called cold air pooling.
Combined with the fact that the canyon bottom gets less sunlight in the winter, resulting in less
surface heating, it can remain cooler than expected at the canyon floor. On occasion, the
temperature in the canyon can be lower than the temperature on the rim. This happens in the
winter, especially in the morning while the sun heats up the canyon rim above. Cool, dense air
has sunk into the canyon and being trapped below warmer air above. When this happens, it’s
called an inversion. On occasion, when the air in the canyon has reached saturation (a
temperature which clouds form), a sea of clouds can form inside the canyon walls.

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Grand Canyon Clouds Inversion: https://www.youtube.com/watch?v=dBm7jgNX3hQ

Radiation Balance
So why does winter see a change in this lapse rate and the presence of inversions in the Grand
Canyon? That has to do with the amount of insolation, or incoming solar radiation, sunlight,
received. As sunlight enters the Earth’s atmosphere, some of it gets absorbed or reflected by the
atmosphere, and the rest is absorbed or reflected by the surface. The earth’s surface warms up and
reemits this energy as longwave radiation, which helps warm the air above.

However, the amount of insolation and longwave radiation changes throughout the course of the
year, as the Earth rotates on its axis around the sun. During the summer, the northern hemisphere
is pointed towards the sun, causing more direct sunlight. During the winter, the opposite occurs,
with the northern hemisphere pointed away. This results in the sun being lower in the sky, and
insolation more spread out across Earth’s surface, and an overall lower amount of insolation
received. This leads to less energy being absorbed by the surface, and less warming of the air,
leading to cooler temperatures. In the bottom of the canyon, this is especially true, as many deep,
shadowed sections of the canyon may see little to no sunlight during the day in the winter, as high
walls block the already low, shallow sunlight.

Watch the shadows in this rafting video: https://www.youtube.com/watch?v=NIicjzP8CwM

Precipitation / North American Monsoon
The Grand Canyon, along with much of the southwest United States, sees a seasonal pulse of
precipitation in the winter and summer, separated by drier periods in the spring and fall. In the
winter, large low-pressure storms from the Pacific sweep across the region, pulling moisture from
the Pacific and bringing soaking rains and snow. The higher and colder North Rim sees the
heaviest snowfall, averaging 142 inches of snow (nearly 12 feet) every winter while the South
Rim sees 58 inches of snow (or a little over 6 feet). The inner canyon rarely sees snow, as any
snow falling overhead melts into rain by the time it reaches the bottom. This disparity in winter
precipitation is largely a product of orographic uplift, with higher regions of the park pushing air
up to elevations which clouds begin to form, leading to precipitation.

The summer precipitation pattern for the Grand Canyon is characterized by the North American
Monsoon. A monsoon is a pronounced seasonal reversal in wind direction (N to S, E to W). The
seasonal reversal of wind direction is associated with large continents. In winter, the wind blows
from land to sea; in summer, it blows from sea to land as the surface pressure changes over land.

9

The North American monsoon is a wind pattern that produces a dry spring with a relatively wet
summer across the southwestern US and northwestern Mexico. In June, a high-pressure ridge in
the upper atmosphere blocks moisture from moving into the Southwest. Winds during this time
generally flow from the west, bringing dry continental air.

As the summer progresses, the high pressure progresses north. This causes a change in winds
over the Southwest. The dry conditions combined with intense direct sunlight produce extremely
hot conditions over Arizona and California. This hot air lowers the pressure over the
southwestern US, creating a thermal low at the surface. By July, this thermal low, along with the
high pressure aloft then begins to draw air from the south, bringing warm, moist air from the Gulf
of California and even the Gulf of Mexico toward Arizona. The increase in moisture, combined
with the hot conditions leads to an increase in precipitation over the southwestern US and
northwestern Mexico around July and August.

Days often begin clear, but strong surface heating, results in powerful updrafts into the humid air,
particularly along the rims. This is because the higher elevation North/South Rim act as focusing
mechanisms for updrafts, with air over the rims exhibiting higher temperatures than air at the
same elevation over the canyon. This imbalance in temperature results in air being more buoyant
over the rims, causing rising updrafts and resulting in powerful thunderstorms, lightning, heavy
localized precipitation, and flash flooding. Storms that move off the rim can dissipate because of
the dramatic drop in precipitation and lack of rising air, and rain that does fall over the canyon
floor can evaporate on its way down, called virga, leading to generally lower precipitation values
over the course of the summer between rims and canyon floor.

Watch this video on canyon rain: https://www.youtube.com/watch?v=10lI2fwA4pY

Satellite view of WINTER SNOW

Satellite view of SUMMER CLOUDS

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Life Zones (basic term used by rangers in the park) or Ecoregions (term more commonly used in
science)
Precipitation, and temperature, are the most relevant variables for determining the ecoregions
within the Grand Canyon. Multiple ecoregions exist within certain temperature or precipitation
regimes (an annual average temperature of 10C, or roughly 50F, has four different habitats that
are possible, depending on the amount of annual precipitation). While the general trend for
precipitation is an increase with height in the Grand Canyon, the annual temperature and other
important factors influencing microclimate temperatures (such as slope or orientation) are going
to determine ecoregions within the Grand Canyon.

Due to the great range in temperatures and precipitation over a relatively small area, the Grand
Canyon sees an incredible diversity of plant and animal life. Five distinct biotic communities
exist in the Grand Canyon’s ecosystem: boreal forest, ponderosa pine forest, pinyon-juniper
woodland, desert scrub, and riparian.

Above 2400 meters (8000 feet), the Boreal Forest is only found on the North Rim. This
community is the coolest and wettest in the park. Life here adapts to an extreme winter climate
and short, frenzied growing seasons. Here, dense dark spruce and fir forests are mixed with
quaking aspen, which drop their golden leaves as winter approaches. These forests are broken by
bright, open meadows filled with wildflowers and birds in the summer. Some species avoid the
harsh winters through hibernation or migration, or through adaption like the evergreen trees and
their tough, narrow needles that resist freezing.

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Between 2100 and 2400 meters (6800-8000 feet), the Ponderosa Pine Forest thrives on both the
North and South Rim, and act as a transition zone between the mixed conifer above, and pinyon-
juniper woodlands below. Air temperatures increase and precipitation decreases slightly here.
Like the mixed conifer forest, this ecosystem is specialized for fire, brought on by lightning
during monsoon season. Tall ponderosa pine trees, with the thick fire-resistant bark stand tall
among thickets of Gambel’s oak. Naturally occurring, low intensity fires clear the forest and add
crucial nutrients to the soil here. These fires reduce competition, allowing trees to grow tall and
healthy.

However, in the past, humans suppressed these natural wildfires, resulting in the buildup of dense
debris and thick underbrush in the naturally open forests. Faster, hotter fires tore through the
forests, consuming even the large trees. Thankfully, we now better understand the role of fire in
these forests and fire managers work to safely restore the forests using prescribed burns and forest
thinning.

Watch this video on the history of fire in the canyon:

Below the canyon edge, between 1500 – 2100 meters (5200-6800 feet), hot dry breezes rise from
inside the canyon in the Pinyon-Juniper Woodland. Thin soils here hold little water, and with
less precipitation (between 10 and 15 inches annually) and warmer temperatures than along the
canyon rim, the pinyon and juniper trees here grow short and gnarled. To conserve water, these
trees have developed waxy coatings on their needles and leaves. Around five feet of snow still
falls in this ecosystem in the winter while summers are very warm.

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The hottest and driest community, the Desert Scrub, is found between 700 and 1500 meters
(2000 and 5200 feet). Life here adapts to extreme heat and a very dry climate. Limited
precipitation, less than 10 inches annually, comes in the form of cool, gentle winter rains and
violent, localized summer monsoon thunderstorms. Drought tolerant desert plants thrive down
here, like yucca, creosote, and ocotillo. Nocturnal animals like bats, ringtails, and owls avoid the
heat of the day.

Generally sharing the same dry and hot climatic conditions as the desert scrub community, the
riparian habitat is found along the Colorado River at the bottom of the canyon, around 700 to
800 meters (2000-2500 feet). This ecosystem can also be found higher in the canyon wherever
water can be found, in hanging springs or creeks located among canyon walls. This habitat is the
smallest in the Grand Canyon but supports the greatest biodiversity. Cottonwood trees, ferns,
willows, frogs, and other unique plants and animals found nowhere else thrive in these small
corridors where water is in constant supply.

The following PDF from the National Park Service gives some more information and background
on these ecoregions in the Grand Canyon if you are interested:
https://www.nps.gov/grca/planyourvisit/upload/grca_ecology

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It’s a bit more complicated than that though. These habitat zones cover a wide elevation gradient,
a result of the north/south facing slopes of the canyon walls. Locations on the south facing walls
receive more direct sunlight and encounter higher temperatures and greater evaporation than
north facing locations. This allows for cooler habitat zones to exist lower in elevation on north
facing walls of the canyon, while habitat zones on the south face exist at a higher elevation. For
example, on the south facing side of the canyon, the pinyon-juniper woodland’s range is between
roughly 1800 – 2100 meters (6800-6000 feet), while on the north face, this habitat zone extends
from roughly 1500 – 1900 meters (6200-5000 feet).

Remote Sensing and NDVI
Remote sensing is a way of observing the Earth without making physical contact with it. In the
case of this lab, remote sensing will be using imagery created by satellites. These satellites
generally rely on energy coming off the Earth’s surface, such as heat (infrared wavelengths) and
color (visible wavelengths).

The NDVI layer in the geovisualization represents the Normalized Difference Vegetation Index
(NDVI) layer. It is a measure of the greenness and health of vegetation. The index is calculated
based on how much red and near-infrared light is reflected by plant leaves. The index values
range from 0 to 1 where higher values (0.3 to 1) indicate areas covered by green, leafy vegetation
and lower values (0 to 0.3) indicate areas where there is little or no vegetation. Areas with a lot of
green leaf growth, indicates the presence of chlorophyll which reflects more infrared light and
less visible light, are depicted in dark green colors, areas with some green leaf growth are in light
greens, and areas with little to no vegetation growth are depicted in tan colors.

Within the Grand Canyon, these are going to generally be related to the life zones found within
the park. Boreal forests represent dark green, and light green represents Pinyon-Juniper, with
Ponderosa Pine forests in between. Low-hot deserts are light brown/gray colored.

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STAGE B:
EXPLORING THE GRAND CANYON MICROCLIMATE AND

VEGETATION GEOVISUALIZATION

The idea of this stage is for you to explore some of patterns observed in physical

geography data on climate and its connection to vegetation. Use these questions to decide if the
information is of enough interest to warrant a deeper investigation in Stage C.

This section explains each type of question and gives you an example. Then, when you

take the quiz on Stage A in canvas, you will see questions very similar to the examples presented
here; however, the questions will not be identical. In fact, different students will be presented
slightly different questions.

B1. QUESTION ON INTERPRETING SURFACE TEMPERATURES

Background for B1: Diurnal temperature cycle and movement of the sun
In the area of the Grand Canyon, this diagram shows the path of the sun throughout the
day at winter solstice and summer solstice. The sun rises in the east, reaches its highest point at
noon, and sets in the west. The amount of solar radiation received at Earth’s surface is greatest
when the sun is highest in the sky.

15

Temperature is of major importance in the Grand Canyon. For animals and plants, as well as
human hikers, the changing temperatures throughout the day and throughout the canyon fluctuate
wildly.

As the sun rises in the east, reaches its highest point at noon, and sets in the west, the amount of
solar radiation (sunlight) a surface receives changes throughout the day. This is especially true in
a place with complex topography such as the Grand Canyon.

Air and surface temperatures lag behind the time of maximum solar radiation (sometimes called
insolation for incoming solar radiation). The reason for the lag in air temperature is that the air is
being heated by both reflected solar radiation and also the infrared radiation that is coming from
the Earth (as it heats up).

B1 EXAMPLE QUESTION:

Fast Travel to the South Rim meteorological station (36.0443° -112.0586°). Then, display the
summer surface temperatures. Look around the area just off the rim, into the Grand Canyon.
These are the steep slopes that have different temperatures. One slope beneath this station faces
towards the east. The other slope faces towards the northwest.

Question: What is the best explanation for what you see?

Hint: The surface temperature data were acquired about 10am in the morning, and think about the
diurnal temperature cycle and how the sun travels through the sky during the day.

Keep in mind that these surface temperatures were taken from remote sensing satellite imagery,
collected at 10 am. This will influence the temperature greatly for your observation. You should
notice a difference in surface heating, as one surface is warming up through the entire morning,
while the other is cast in shadows until the afternoon.

Once you answer this question, think about what the surface heating would look like through the
whole day. The surface temperatures shown can only be a snapshot when the sensor is collecting
data. If the sensor acquired data in the afternoon, the images would look quite different.

16

B2. QUESTION ON NORTH VS. SOUTH EXPOSURES IN DIFFERENT
SEASONS

Background for A2: How noon sun angle changes throughout the year

Look at the diagram of the “Apparent Path of the Sun Across the Sky” in the background
for B1 on a previous page. Notice that at the latitude of the Grand Canyon, the angle of the sun at
noon is much lower at winter solstice than summer solstice.

The reason is that Earth is tilted 23.5o on its axis. As a result, as it orbits around the sun
throughout the year, the northern and southern hemispheres are either tilted towards the sun
(summer) or away (winter). This results in the sun appearing lower or higher in the sky depending
on the season. The angle the sun makes from directly overhead to its location is called the zenith
angle, while from the horizon is called the solar angle.

We can calculate the zenith angle if we know the latitude of the location we’re interested
in and latitude of the subsolar point, or where the sun is directly overhead on a given day. For this
section, we’ll use the summer and winter solstices for the northern hemisphere, around June

21

and December 21, respectively.

Summer Solstice: subsolar point is at the Tropic of Cancer (23.5o)
Winter Solstice: subsolar point is at the Tropic of Capricorn (-23.5o)

Noon solar angle = 90 – [Number of degrees of latitude between your site and the location of the

subsolar point]
Summer solstice noon solar angle = 90 – (36 – 23.5) = 90 – 12.5 = 77.5° above the horizon.
Winter solstice noon solar angle = 90 – (36 – -23.5) = 90 – 59.5 = 30.5° above the horizon.

The reason you subtract a negative value for the winter solstice is because the subsolar point is in
the opposite hemisphere as our Grand Canyon location, across the equator.

17

B2 EXAMPLE QUESTION:

Fast Travel to the South Rim meteorological station (36.0443° -112.0586°). Then, display the
winter surface temperatures. Look around the area just off the rim, into the Grand Canyon.
Compare the slope that faces north (and a little west) to the slope that faces to the east.

Question: What is the best explanation for what you see?

Hint: Think about the angle of the sun and how it changes throughout the day and also how it
changes throughout the year. Think about how much sun a south-facing slope would receive vs. a
north-facing slope in winter. North-facing slopes would receive little to no sunlight at winter
solstice, and only the steepest north-facing slopes would be shaded (slopes greater than 77.5˚ or
almost vertical.

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B3. QUESTION ON TEMPERATURE CONTROLS ON PLANTS

Background for B3: Factors that influence plant distribution, focusing on
temperature and key plants in and near the Grand Canyon

Many factors influence the biogeography of plants. Plants have ecological niches
(the combination of conditions required for reproduction). They need energy and
nutrients. The need to be able to disperse and colonize new locations, and disturbances
like fire influence their distribution. In particular, this lab focuses on temperature
influences at the low (winter) end and also the high (summer end). Typical temperature
limitations are shown in this graph by Professor Karen Lemke.

At the higher elevations of the geovisualizations on the North Rim’s Kaibab
Plateau, spruce is found with its ability to tolerate extreme low temperatures (e.g. -40˚ F)
and its preference for lower summer temperatures (e.g. 60-76˚ F).
At the lower elevations where trees are found (typically Juniper trees, such as
Utah Juniper). These junipers often live to be hundreds of years old, and they are in mean
annual temperatures that range from below freezing to 104˚ F. However, if it is much
hotter for a prolonged period of time, they are not usually found.
Keep in mind that the temperature chart above is for air temperature. Air
temperature has to be measured at meteorological stations, but surface temperature can be
imaged from space. Thus, the game displays surface temperatures with the following
scale:

19

The NDVI layer in the geovisualization represents the Normalized Difference Vegetation Index
(NDVI) layer. It is a measure of the greenness and health of vegetation. The index is calculated
based on how much red and near-infrared light is reflected by plant leaves. The index values
range from 0 to 1 where higher values (0.3 to 1) indicate areas covered by green, leafy vegetation
and lower values (0 to 0.3) indicate areas where there is little 28 or no vegetation.

Areas with a lot of green leaf growth, indicates the presence of chlorophyll which reflects more
infrared light and less visible light, are depicted in dark green colors, areas with some green leaf
growth are in light greens, and areas with little to no vegetation growth are depicted in tan colors.
Within the Grand Canyon, these are going to generally be related to the life zones found within
the park. Boreal forests represent dark green, and light green represents Pinyon-Juniper, with
Ponderosa Pine forests in between. Low-hot deserts are light brown/gray colored.

B3 EXAMPLE QUESTION:

Fast Travel to a high point on the Kaibab Plateau, where the edge of the plateau faces
northeast (36.3186° -112.0065°). The avatar is just off the edge of the plateau. If you
change the camera angle (pull it back and high above), you can see the edge of the East
Rim of the Kaibab Plateau as shown here:

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Compare the dark green color with the NDVI scale above. You can see that this area is
boreal forest with a lot of spruce (genus Picea) trees and some fir (genus Abies) trees. In
particular, the most common trees here are Picea engelmannii and Abies lasiocarpa.
However, you do not need to know the Latin names for plants in this lab. We present just
the common names as they are used in the Grand Canyon National Park.

Question: Using the temperature scale in the geovisualization (presented above for
your convenient), what are the 10 am typical summer surface temperatures in this

area and the typical winter surface temperatures. Select the best answer.

Hint: Do not fret much about precision. The answer will have a range of temperatures,
and the different answers will vary enough so that there should not be a worry about mis-
interpreting the scale.

Correct Answer: In winter, temperatures range from 20-35˚F, while in summer they are
in the 80-95˚ F range

Explanation: If you examine the screenshots of this location for summer and winter, you
can match the colors and estimate the range of temperatures where there’s the darkest
green spruce. Keep in mind that these are 10 am surface temperatures, and the air
temperatures at that time will be slightly cooler at 10a,. Also, keep in mind that
northeast-facing exposures like this do not get nearly as hot as west-facing exposures that
really heat up in the afternoon. It is the reason why boreal plants like spruce and fir can
grow here.

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B4. QUESTION ON ELEVATION’S INFLUENCE ON TEMPERATURE

Temperature gradient is a term to describe how temperature changes with altitude. You have
likely encountered or will encounter this concept in this course.

This question will focus on the concept of temperature gradients with respect to the ground
surface temperature, and how these temperatures change seasonally. The temperature of the
ground is a decent proxy for actual air temperature, although the air temperature is going to
alternate due to circulations inside the canyon and ground surface temperatures are influenced by
surface cover (water, vegetation, etc.) and generally more extreme than air temperatures.

You should be familiar with the idea that complex topography is an important factor on
determining the amount of sunlight that can reach the surface of the canyon. Sunlight that makes
it to the surface heats the ground up, and warms the overlying air. However, seasonal changes in
solar angles and surface heating will alter the temperature gradients between the bottom of the
canyon and rim.

For example, the near-surface temperature gradient (air temperature we experience hiking)
between rim and river can be as high as 8.2˚C per 1000 meters (5.5˚ per 1000 feet) in summer,
but in winter, the temperature gradient lowers to around 5-6˚ C per 1000 meters. These values are
just generalizations. The real near-surface lapse rate depends a lot on the complex topography.

So keep in mind that so much more influences the temperature you experience when you hike in
the Grand Canyon or stroll around the rim. The list of factors includes: cloud cover, surface
heating that occurs, reflectivity of the surface, the moisture in the ground, how the surrounding
topography and plants release or absorb heat, pooling of cold air in low spots, movement of air up
and down the canyon, and movement of air upslope and downslope. These and other factors make
the microclimatology of the Grand Canyon complex.

B4 Example Question:
How does the surface temperature gradient change between the North Rim and Colorado
River locations between summer and winter?

Fast Travel to the meteorological station at the bottom of the Grand Canyon, the Colorado River
(36.0976° -112.0969°). For this example, we’ll jump up just above the river to make our
observations, because the we want to look at the surface temperature of the ground, not the river.

First, make a note of its elevation. Then, in the geovisualization, click on the summer and winter
surface temperatures and measure the surface temperature where the avatar is standing using the
temperature key.

You will be using the elevation and seasonal surface temperature for to estimate the lapse rate
between the bottom of the Grand Canyon and the North Rim. Thus, you need to repeat these steps
for the meteorological station on the North Rim, that you can get there via fast travel (36.2274° –
112.0296°).

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NOTE: When determining the temperature value, use the color that the character most stands
upon – use your best judgement, just know you won’t be tricked in the Canvas questions.

You can use this table, if you wish, to help you organize the observations and calculations

Elevation (meters) Summer Surface Temperature
Winter Surface
Temperature

Location 1 ˚F ˚C ˚F ˚C

Location 2 ˚F ˚C ˚F ˚C

Change from bottom to
top of Grand Canyon Change in ˚C: Change in ˚C:

Surface temperature
gradient ˚C per 1000 m —

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Elevation (meters) Summer Surface Temperature
Winter Surface
Temperature

Colorado River 721 125˚F 51.6˚C 50˚F 10˚C

North Rim 2611 95˚F 35˚C 35˚F 1.7˚C

Change from bottom to
top of Grand Canyon 1890 Change in ˚C: 16.6 Change in ˚C: 8.3

Surface temperature
gradient ˚C per 1000 m — 8.8C / 1000m 4.4C / 1000m

ANSWER: The summer surface temperature gradient from the Colorado River to the North
Rim is about 8.8˚C/1000 m, while the winter surface temperature gradient is lower, at about
4.4˚C/1000 m.
An incorrect answer would likely stem from dividing the temperature difference by 1890
instead of 1.89. This is a calculation for the temperature change per kilometer (1000m).
So what you should see is the change in temperature between the top and bottom of the
canyon is greater during the summer than during the winter. Try to see if this is the case for your
question, and think of the explanation for why this might be.
For this example, it’s a bit more complicated. The location of the Colorado River is also
influenced by the temperature and evaporation of the Colorado River itself, so the summer
temperature especially is cooled by a several degrees. Hopefully by now, you’ve started to
connect the influences of how seasonality and complex topography impact climate within the
Grand Canyon. Keep thinking about this, as you’ll look more in-depth at this concept in later
sections.

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STAGE C: More detailed investigation of the geovisualization of the
Grand Canyon’s microclimate and vegetation

The idea of this stage is for you to explore some patterns observed in physical geography

data on climate and its connection to vegetation. However, you are the one who decides if the
topic is of enough interest to warrant a deeper investigation in Stage B.

This section goes over each type of question administered by canvas and gives you an

example. Then, when you take the quiz on Stage C in canvas, you will see questions very similar
to the examples presented here; however, the questions will not be identical. In fact, different
students will be presented slightly different questions.

The detailed investigation is broken into several sorts of tasks:

1st Task: Using meteorological stations data and the geovisualization, investigate the connections
between precipitation, elevation in the canyon, and the types of plants that are growing.

2nd Task: Investigate precipitation trends across the Grand Canyon, looking at seasonality and
elevation.

3rd Task: Investigate microclimates within the canyon caused by elevation, slope, orientation,
surface cover, and other factors.

4th Task: Investigate the elevation of treelines in the Grand Canyon (where juniper trees no longer
grow) on different exposures (north-facing and south-facing)

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1st Task: Using meteorological stations data and the geovisualization,
investigate the connections between precipitation, elevation in the
canyon, and the types of plants that are growing.

Question Overview For 1st Task
There are meteorological stations in and just above the Grand Canyon used in this lab.
You will be supplied randomly generated questions that task you with analyzing the information
from different stations. Some of the information will come from the geovisualization (bold font in
table below). Some will come from information supplied to you in a question. You may find this
table useful in compiling your observations of a forested station site (C1.1) and a non-forested
station site (C1.2).

Station Name: Geographic Coordinates: Elevation:

Annual Precipitation: % Precip During Summer
Monsoon (Jul-Sep):

June-Aug Summer Max Temps

Summer Ground Temp Winter Ground Temp Months Min Temp Freezing:

NDVI Estimate Using This Scale

You will be asked three questions in canvas related to this task. One question will ask for
an analysis of a station with trees nearby. Another question will ask for an analysis of a station
without trees. The third question will ask a comparison question.

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Example Material for Questions 1.1 and 1.2 for Task 1: Cedar Ridge

What is the basic climate-vegetation relationships that you can observe at the Cedar Ridge
station from the geovisualization and information supplied in the question? Select answer
that best matches the available information.

Location: 36.0646° -112.0738°
Photograph of the area

Elevation as determined in the geovisualization: 1620m

Cedar Ridge Climate Variables
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Temperature Max 46.8 50.4 57.8 65.9 76.4 86.9 90.3 86.8 80.0 68.0 55.6 46.2
Temperature Min 26.0 28.3 33.2 39.4 47.3 54.9 60.6 58.7 52.3 42.5 32.9 26.0

Precipitation 1.3 1.3 1.5 0.9 0.5 0.3 1.5 2.1 1.3 1.2 1.0 1.1

This graphic from Professor Karen Lemke indicates that the freezing temperatures experienced in
December through February can limit many plants, but that the maximum temperatures typically
do not exceed damaging temperatures.

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NDVI INTERPRETATION: The biomass scale (NDVI) in the game screenshot below
matches the vegetation survey information. The color is not a dark green of a dense forest.
Neither is it a brown of no trees. The site is near the lower elevation where you would find trees
on the south rim.

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THIS WOULD BE AN EXAMPLE OF A CORRECT ANSWER:
At an elevation of 1620 m, precipitation averages 14 inches at the station. About a third of
the precipitation falls during the monsoon summer thunderstorm season (July-September) with
the remaining coming during the cooler months of October through April. May and June are the
driest months. Maximum temperatures range from the upper 40s ˚F around winter solstice to the
upper 80s-low 90s ˚F around summer solstice. However, these are air temperatures. The ground
temperatures experienced even in the late morning about 10 am in summer can be considerably
hotter than the air temperature.
Minimum temperatures do typically fall below freezing, both recorded at the meteorological
station and seen areas shaded from the sun. These conditions have led to the growth of small trees
(e.g. oak, ash, juniper) and shrubs (e.g. mountain mahogany).

THE INCORRECT CHOICES would have false information mixed in. They may have the
elevation wrong. They may have a temperature range wrong. They may have the wrong mix of
summer and winter presentation. The intent is not to trick you, but to promote careful
observations on your part. The hope is that you gather in a file on your computer the sorts of
information you see here.

The third question (C1.3) for Task 1 asks you to compare your observations for the forest
site (question 1) and a desert site (question 2). The questions in the pool will have slightly
different wording, but this is a typical one.

QUESTION: Match the microclimate information to the impact on vegetation at forested and
desert sites in and around the Grand Canyon. Select the best matches.

QUESTION SETTING: You analyzed microclimatology and vegetation information from a site
in and around the Grand Canyon with trees (mostly forested) and without trees (desert). You
compiled the annual precipitation values and the seasonality of this precipitation. You observed
the extremes of ground surface temperatures found in winter at 10am and in summer at 10am.
You analyzed air temperatures extremes of the coldest minimums and the hottest maximums, and
you tabulated precipitation totals and seasonality, and thought about the issue in terms of the
impact of these temperatures on plants contextualized by this diagram:

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2nd Task (C2.1): How does elevation impact precipitation?

Even though the Grand Canyon is roughly 10 miles wide, the change in elevation causes dramatic
fluctuations in precipitation. First, we’ll look at the basic relationship between precipitation and
elevation in the Grand Canyon.

Using the images below, calculate the annual precipitation gradient per kilometer between
Cedar Ridge and the South Rim weather station. [There will be another question in canvas
about calculating between the location and the Rim weather station].

EXAMPLE: What is the precipitation gradient per kilometer between the Cedar Ridge
climate station (36.0646°, -112.0738°) and the South Rim Station (36.0442, -112.0586)
annually?

First, calculate the annual precipitation for both locations. Cedar Ridge has an annual
precipitation of 14 inches, while the South Rim has an annual precipitation of 15.9 inches. To
find the kilometer rate of change, you would find the change in elevation between two locations
(South Rim: 2191m , Cedar
Ridge: 1620m) and divide
that by 1000 (.571).

The precipitation gradient
will be the difference in
annual precipitation divided
by the 100 m change
GRADIENT = (15.9 –
14in) / (.571km) = 3.4
inches per kilometer.

Your calculations will look
at gradients over larger
distances into the canyon,
and you’ll compare the
North Rim gradient to the
South Rim gradient.

30

2ND TASK QUESTION (C2.2): Analyze the Lapse Rate in the Winter

You should have observed a strong gradient between canyon bottom and rims, as well as a
change in gradients between South/North rim. The next task will be to understand why this
gradient exists as well as why there is a difference in precipitation between North and South
Rims.

In the summer, precipitation is generally higher on the rims compared to the canyon floor due
multiple factors. Higher elevation locations are typically the starting locations for monsoon
season thunderstorms. Storms that move over the canyon often dissipate as well, and any rain that
falls over the canyon has a chance of evaporating before the rain hits the canyon floor. Lastly, the
high elevation of the North/South Rims can influence orographic lifting, which is particularly
prevalent in winter precipitation, which we’ll look at next.

HOW TO THINK ABOUT THIS QUESTION:
When air lifts up above the surface, it cools at what is called the dry adiabatic lapse rate, or
roughly 10C per 1000m (1C per 100m). This cooling will eventually lead to the air reaching its
dew point temperature.

Then, when an air parcel reaches dew point, clouds begin to form, and with enough uplift,
precipitation can occur. If the air continues to rise, it will cool off at the wet adiabatic lapse rate.
The exact wet adiabatic lapse rate will vary depending on how much water vapor is in the
atmosphere.

For this lab, you will use the rate of 6C per 1000m (.6C per 100m). This is because as water
vapor (a gas) condenses into a cloud (liquid), it gives off a bit of heat during the change between
gas and liquid. This heat slightly warms the air parcel, which is still cooling as it rises, leading it
to cool at a slower rate (10 vs 6) compared to the dry adiabatic lapse rate.

Please use the elevations found in the earlier sections of the lab and round them to the closest
100m value. The North Rim has an elevation of roughly 2600 meters, and the Colorado River has
an elevation of roughly 700 meters, while the South Rim has an elevation of 2200 meters

Locations in the Grand Canyon experience significant winter precipitation brought by strong mid-
latitude cyclones pulling moisture from the Pacific Ocean. The dramatic changes in elevation
mean different types of precipitation fall at different locations within the park. Even if there is no
precipitation at the South Rim, there still might be precipitation at the North Rim, simply because
it’s pushing the air mass moving over the Grand Canyon up higher into the atmosphere.

Think about an air mass south of the Grand Canyon, at an elevation of 1500 meters and it is
pushed up by the motion of the atmosphere onto the South Rim, at 2200 meters in elevation. You
have the knowledge now to estimate if there would be clouds/precipitation if you just knew the
air temperature/dew point of that air mass when it started..

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EXAMPLE: Consider an air mass with a temperature of 7˚ C and a dew point of 3˚ C to start
with. The air miss is then lifted from 1500m up to the South Rim at 2200m.
It will first cool off at 10˚ C/km (1C/100m). When it reaches dew point at 1900m, clouds
begin to form, and precipitation can begin occurring if the cloud is lifted further.
Since clouds have started to form, = it has reached dew point. The parcel is saturated, so you
now use the wet adiabatic lapse rate (6˚ C/km or 0.6˚/100m). Continuing at this rate, the
temperature of the air parcel at the South Rim is 1.2C and if the parcel is lifted even more the
height of the North Rim, the temperature drops to -1.2˚C. This means that if precipitation is
falling, the South Rim will have rain, while the North Rim will have snow (since -1.2˚ C is below
freezing).

ELEVATION TEMPERATURE CONDITION

2600
(North Rim)

-1.2 SNOW

2500 -0.6 SNOW

2400

0.0 SNOW

2300 0.6 RAIN

2200
(South Rim)

1.2 RAIN

2100

1.8 RAIN

2000

2.4 RAIN

1900 3.0 DEWPOINT –
clouds form

1800 4.0 Not saturated

1700 5.0 Not saturated

1600 6.0 Not saturated

1500
(Start)

7.0 Not saturated

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3rd Task: Investigate Temperature Stresses for plants in and around
the Grand

Brief Review of the Importance of Temperatures on Plants

In the exploratory Stage B of this lab, the third question examines the role of
temperatures on trees. The highest elevations around the Grand Canyon have spruce trees that are
not very sensitive to very cold temperatures. They have the ability to survive at temperatures of –
22˚ F (-30˚C) where other plants cannot.

Juniper trees (e.g. Utah Juniper), in contrast, cannot survive super cold temperatures.
They also cannot survive super hot temperatures for very long. Still, they very hardy. They can
tolerate freezing and 100˚ F temperatures- just not the extremes found around the Grand Canyon.

This graphic made by Professor Lemke gives a snapshot of some of the temperature
issues associated with different types of plants.

While the graphic above was made for air temperature measurements (e.g. meteorological
stations), the ground temperature information in the geovisualization still applies. Extreme cold
and extreme heat can influence whether a particular type of plant can survive. For your reference,
this is the key for ground temperatures seen in the geovisualization.

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3rd Task questions related to temperature differences in and around the
Grand Canyon

There are dozens of ways that microclimates can develop and influence plants. The ways
vary at different spatial scales. For example, on the scale of tens of centimeters, the orientation of
a boulder can influence whether precipitation is channeled to a spot where a tree might or might
not germinate.

The temperature data in the geovisualization is at the highest resolution available at the
present time – at least for the coverage of the entire Grand Canyon. Thus, this investigation is
limited to the resolution of about a 30 m pixel. Those are the squares seen in the geovisualization
for winter and summer ground temperatures. At this scale, you can investigate/analyze six
connections between topography and temperature that are presented below.

QUESTION: Match the locations with the primary factor influencing temperature . Each
location also has the season (winter or summer) that you should investigate. Try to bring
the game camera angle up higher, so that you can get an overview of the location and you
can spin the view. Make the best matches between the temperatures you see for each
location/season with the effect of topography on temperature.

You will be given different locations in the geovisualization to “Fast Travel” to and study. Then,
you will match those locations with the effect of the topography. The six connections that you
will try to identify your location as are presented below:

ALREADY STUDIED IN THIS LAB:
Diurnal effect of the 10am time of data
acquisition – explaining why east-facing
slopes are often warmer than west-facing
slopes
The satellite gathering the temperature
data images at about 10am in the morning.
Thus, the east-facing slopes have accumulated
more insolation than the west-facing slopes.
This image of the South Rim of the Grand
Canyon was presented earlier in the PDF file.

ALREADY STUDIED IN THIS LAB:
Around the time of winter solstice, North-
facing slopes that are steeper than the angle
of the sun at noon receive no solar
radiation.
This slope has an angle of 35˚, and the
rabbit is facing south, so the slope is facing
north. Because the noon sun angle at winter
solstice is only 30.5˚, no sunlight hits this
slope.
The effect on plants is greatest in winter at
high elevations, because the result can be
severe cold temperatures.

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Cold Air Drainage, especially in winter. The
game screen on the right shows a small
drainage on the Kaibab Plateau where cold air
has collected

Evaporative cooling – In the summer
temperature image, the Colorado River is able
to exert a cooling effect on the 30 m pixels.
This effect is often several pixels wide.
The effect of water evaporative cooling is
not seen in the winter imagery around the
Colorado River. The reason is that the surface
temperatures around the river are sometimes
colder or similar to the river itself.

Flat treeless surfaces as heat accumulators
– Stage B has a section called “Radiation
Balance”, which is a significant topic in GPH
111.
Flat surfaces can accumulate a lot of
energy in summer, when sun angles are high.
Solar radiation starts the process. However,
treeless surfaces with lots of exposed rock
play a big role in absorbing lots of the solar
radiation. The result is that these are some of
the hottest surfaces in and around the Grand
Canyon.

35

Summertime north-south exposure
contrasts. Wintertime temperatures in the
lower desert portions of the Grand Canyon are
not severe. Freezing rarely occurs, and only
for a few hours in the morning. Maximum
temperatures are not extreme.
In contrast, summer temperatures can
cause great stress for plants, especially when
air temperatures exceed 104˚ F and ground
temperatures exceed 120˚ F.
Even though sun angles are much higher in
summer, the contrast of south (warmer)-facing
and north (cooler)-facing slopes can influence
plants.
The rabbit is standing on the side of a river
canyon that has facing north, where the sun’s
rays are not as direct.
The hotter surface temperatures on the
other side of the canyon are because those
surfaces are facing south, and they are getting
more direct sunlight.

The questions for Task 3 will be matching. You will be given different locations in the
geovisualization to “Fast Travel” to and study. Then, you will match those locations with the
effect of the topography.

SUGGESTION ON WHAT YOU MIGHT DO IN TAKING THE QUIZ:
You can speed up the answering of these questions by taking full screenshots of the
different locations. Try setting the default location for the screenshots to your desktop.
Then, they toggled the game to your ‘task bar’ when you are done traveling and taking
screenshots.
This will allow you to see the latitude/longitude coordinates and also the compass rose
for reference in answering the matching question of the sort exemplified below.

36

4th Task: What influences lower treeline in the Grand Canyon?

Exposure of a slope can have a dramatic impact on vegetation due to differences in surface
heating and the resulting evaporation. What you’ll be looking at next is how treeline varies
between north versus south facing slopes on walls in the Grand Canyon. This portion of the lab
will task you with finding the lowest elevation for the treeline on either north facing or south
facing slopes, comparing 3 different locations.

You will have two questions like this:

2 questions like this. One is for north-facing slopes. The other is for south facing slopes.

QUESTION: Fast travel to the three coordinate locations in the geovisualization. What is
the slope orientation (north facing, south facing) and mean (average) height of the
transition zone between desert (brown, no trees) and pinyon-juniper woodland (green, leafy
trees) for these locations?

Part of the task has you understand the compass in the geovisualzation. What direction is
the slope you are sent to facing. Then, the other part is taking the elevations and averaging them.
Two examples are given below, but you’ll have three spots in the question. Look only at the cliff
you begin at; you may see spots of vegetation down below your fast travel location, but those are
not related to answering this question – they could be related to a natural spring and associated
riparian habitat. Just focus on the treeline present on the cliff the coordinates take you to.

For this simple example, Treeline elevation = (1051 + 1201) / 2 = 1126 meters.

WARNING: the answer choice in canvas will probably not be EXACTLY what you calculated.
The reason is that where you locate your avatar will be slightly different from where we put our
avatar. These slight differences will mean that you should pick THE CLOSEST ANSWER. The
incorrect choices will be either be far off or facing the wrong direction.

The lab does not end with this question. Hopefully, you feel empowered to try to
synthesize everything you’ve learned in writing the essay. But there’s no penalty for deciding not
to participate in the next section.

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Stage D: Synthesis

As with all assignments in GPH 112, there is no grade penalty for skipping this assignment. At
the same time, many students have a lot of interesting thoughts about the lab that they just
completed, and this essay is a great chance for you to bring these thoughts together.

The assignment is to write four paragraphs. Each paragraph is worth a maximum of 0.5 points.
We are not English teachers, but proper grammar and well-composed sentences make it a lot
easier for us to read your ideas. Still, our focus rests in the details that you use to support your
thinking.

Paragraph 1: What is the connection between altitude, microclimate, and vegetation in and
around the Grand Canyon? Please give examples from the lab, and you can also include your
own observations.

Paragraph 2: What is the connection between the direction a slope faces (aspect), microclimate,
and vegetation in and around the Grand Canyon? Please give examples from the lab, and you can
also include your own observations.

Paragraph 3: Was there anything in particular that struck you as particularly interesting about the
connection between topography, microclimates, and vegetation? Please do not simply write
down a sentence. Explain your idea, and elaborate with at least a few sentences.

Paragraph 4: Please provide you thoughts on this geovisualization as a tool to investigate
connections between microclimate and the biomass (abundance) of vegetation. Please do not
simply write down a sentence. Explain your idea, and elaborate with at least a few sentences.