GEOG 271 pt 2

Question 1

What does the Stefan-Boltzmann equation tell us?

Answer 1

All the radiation emitted from a target, so everything under the curve.

Question 2

What is an atmospheric window?

Answer 2

A part of the electromagnetic spectrum in which the atmosphere does not absorb all of the incident energy but transmits it effectively.

Question 3

If we wanted to differentiate between a manmade and natural waterbody, what image interpretation ‘tools’ could we use?

Answer 3

Association, shape and pattern

Question 4

What is the difference between a black and gray body?

Answer 4

The emissivity of the body or material.

Question 5

Why does the sky appear blue?

Answer 5

Rayleigh scattering, Light travels a shorter distance

Question 5

What is radiometric resolution?

Answer 5

The number of gray levels in an image.

Question 6

A standard false colour composite includes which satellite bands?

Answer 6

Near-infrared, Red, Green

Question 7

What is a specular surface?

Answer 7

A surface that reflects radiation like a mirror.

Question 8

Which is the best band(s) to use if we wanted to map the bathymetry of lakes?

Answer 8

Green

Question 9

Which biophysical parameter is responsible for the high reflectance of near-infrared from vegetation?

Answer 9

Cell structure

Question 10

We know that NDVI was purposely developed for monitoring vegetation growth. Which surface would have the lowest NDVI?

Answer 10

Early season crops

Question 11

Which bands of Landsat-8/9 are best for discriminating between snow and cloud cover ?

Answer 11

Bands 6 and 7

Question 12

Smaller snow grains have what impact on reflectance from snow cover?

Answer 12

increased reflection of solar radiation for all wavelengths

Question 13

What is the impact of increased algae on reflectance from waterbodies?

Answer 13

To increase reflectance of green light

Question 14

What is the impact of decreased organic matter content in soils?

Answer 14

To increase reflectance at all wavelengths

Question 15

Which of the following do not follow a near-polar orbit?

A)

Landsat

B)

Terra

C)

GOES

D)

MODIS

E)

SPOT

Answer 15

GOES

Question 16

If we wanted to study a change in the health of a forest since 1985, which satellite would be the best choice?

A)

Landsat

B)

MODIS

C)

SPOT-7

D)

Worldview-3

E)

Planet DOVE

Answer 16

Landsat

Question 17

If we wanted to measure the size of individual tree crowns in a local neighborhood, which satellite would be best?

A)

Landsat

B)

GOES

C)

MODIS

D)

SPOT

E)

Worldview-3

Answer 17

Worldview-3

Question 18

Why do thermal remote sensors not look at the full range of wavelengths between 3 - 14 μ?

Answer 18

There are areas with 0 atmospheric transmission

Question 19

If two objects have the same kinetic temperature but different radiant temperature - what does that mean?

Answer 19

The object with a higher radiant temperature has a higher emissivity

Question 20

Which of the following materials exhibit large temperature fluctuations during a 24-hour period on a sunny day?
A)

Water

B)

Moist soil

C)

Rocks

D)

B and C

E)

A and B

Answer 20

Rocks

Question 21

Thermal inertia is a measurement of the thermal response of a material to temperature changes. Which of the following variables influence the thermal inertia of a material?

Answer 21

Density, thermal capacity, thermal conductivity

Question 22

What is a selective radiator?

Answer 22

A material that is characterized by variable emissivity values at different wavelengths

Question 23

If looking at a thermal image acquired during nighttime, what landcover might you expect to have the highest brightness temperature?

Answer 23

Urban

Question 24

What is the basic principle behind why we can obtain measurements in the thermal wavelengths of the electromagnetic spectrum?

Answer 24

All objects with a temperature greater than 0 K emit energy in these wavelengths, There is some relation between an object's radiant and kinetic temperature

Question 25

If we wanted to observe a forest fire with a temperature of 800 K, what range would we want our sensor to capture?

Answer 25

3 - 5 μm

Question 26

What does RADAR stand for?

Answer 26

Radio Detection and Ranging

Question 27

What is the main difference between active and passive sensors?

Answer 27

Active sensors emit their own source of EMR

Question 28

Why is SAR the best option for RADAR imagery from space?

Answer 28

Antenna length

Question 29

Which of these is an advantage of RADAR over an optical system?

Answer 29

Can be used at any time of day, Can penetrate cloud cover (all-weather)

Question 30

What would we expect the dominant scattering mechanism to be for a swamp with emergent vegetation (trees) when using an X-band system?

Answer 30

Volume Scattering, Double Bounce

Question 31

What determines whether water appears bright or dark in a RADAR image?

Answer 31

Roughness of the water, The wavelength of the RADAR sensor

Question 32

If we wanted to study soil moisture in the Amazon rainforest, which wavelength would we use?

Answer 32

L-band

Question 33

When interpreting thermal infrared we are mainly looking at surface (skin) temperature. For passive microwave, what are we primarily interpreting?

Answer 33

Emissivity

Question 34

Under what circumstances would the decrease in brightness temperature from soil be lowest with increasing moisture content?

Answer 34

Soil is cooler

Question 35

If we wanted to differentiate between dry and wet snow would we want to use a high or low passive microwave frequency? Why?

Answer 35

High frequency, scattered by dry snow