Fundamentals of remote sensing

Question 1 of 31

1

Which of the following would NOT normally be considered as a form of remote sensing?

Select one of the following:

Sonar
Radar
Seismology
Ultrasound
Gravimetrics
None of the above. They are all forms of remote sensing.

Explanation

Question 2 of 31

1

Electromagnetic radiation can be described completely using wavelength, wave velocity, frequency and amplitude?

Select one of the following:

True
False

Explanation

Question 3 of 31

1

Label all the key points in this diagram of the temperature profile through the atmosphere. You need to name the zones defined by the temperature changes, the boundaries between them and also label the altitude axis (approximately)

Drag an answer into the correct orange point.

Tropopause

Heliopause

Thermopause

Stratopause

Mesopause

Troposphere

Heliosphere

Atmosphere

Hydrosphere

Stratosphere

Mesosphere

Thermosphere

20

10

25

40

50

70

60

80

Explanation

Question 4 of 31

1

Label the different regions of the electromagnetic spectrum.

Drag an answer into the correct orange point.

Visible

Gamma rays

Optical

Electromagnetic

Radar

Radio

Microwave

Sonic

Seismic

Millimetre

Sub-millimetre

Thermal IR

Near Infra-Red

Ultra-violet

X-rays

Explanation

Question 5 of 31

1

Label this EM Spectrum with the typical processes that emits radiation of that approximate wavelength.

Drag an answer into the correct orange point.

Molecular transitions (e.g. rotation)

High energy molecular transitions

Non-ionising electron transitions

Ionising electron transitions

Thermo nuclear transitions

Nuclear transitions

Explanation

Question 6 of 31

1

Electromagnetic radiation can be created when... (note: there may be more than one answer)

Select one or more of the following:

an electron moves from one energy state to a lower energy state.
an molecule moves from one kinetic energy state to a lower energy state (e.g. vibration or rotation states).
an atomic nucleus changes from one energy state to a lower energy state.
an electron moves from one energy state to a higher energy state.
an molecule moves from one kinetic energy state to a higher energy state (e.g. vibration or rotation states).
an atomic nucleus changes from one energy state to a higher energy state.
None of the other answers are correct.

Explanation

Question 7 of 31

1

Which of the following best describes why a "blackbody" is black?

Select one of the following:

It is invisible to the naked eye.
It completely absorbs all wavelengths of visible light.
It completely absorbs all wavelengths of EM radiation, including the ones we can't see.
It absorbs all wavelengths of EM radiation equally well, including the ones we can't see.

Explanation

Question 8 of 31

1

Which of the following statements is NOT true?

Select one of the following:

Geostationary satellites take 24 hours to orbit the Earth and therefore always remain above the same point on the ground.
Geostationary satellites are never in near-polar orbits -- they are always in equatorial orbits.
Earth observation satellites in a sun-synchronous orbit travel slightly East-to-West -- the opposite direction to the rotation of the Earth.
Some Earth observation satellites in LEO are near-equatorial, so that they only cover the tropical regions.
Sun synchronous orbits are always arranged to have a local solar time beneath the satellite at approximately 10:00-10:30 in the morning so as to minimise the cloud cover.

Explanation

Question 9 of 31

1

The albedo of Earth is the fraction of incident sunlight...

Select one of the following:

absorbed at Earth’s surface, and has a value of 49%
reflected at Earth’s surface, and has a value of 5%
absorbed by Earth’s surface and atmosphere, and has a value of 31%
reflected by Earth’s surface and atmosphere, and has a value of 31%
absorbed by Earth’s surface and atmosphere, and has a value of 69%

Explanation

Question 10 of 31

1

If a represents Earth’s albedo and P is the total power of sunlight incident on Earth, then the power radiated by Earth to space is approximately...

Select one of the following:

aP
(1-a)P
1-aP
a(1-P)
a

Explanation

Question 11 of 31

1

An object will appear red to the naked eye if...

Select one of the following:

It scatters all visible wavelengths equally.
It scatters only red wavelengths and absorbs all the other visible wavelengths.
It absorbs only red wavelengths.
It transmits only red wavelengths.

Explanation

Question 12 of 31

1

An object will appear white to the naked eye if...
(Note: more than one answer may be correct).

Select one or more of the following:

it scatterers all visible wavelengths equally.
it absorbs all visible wavelengths equally.
it scatters all wavelengths equally.
it transmits all wavelengths.
it absorbs all wavelengths equally.

Explanation

Question 13 of 31

1

Approximately what proportion of the mass of the Earth's atmosphere lies within the Troposphere?

Select one of the following:

100%
95%
90%
50%
15%

Explanation

Question 14 of 31

1

Which of the following in NOT an advantages of satellite measurements?

Select one of the following:

Consistent measurements globally.
Rapid large area coverage.
Near continuous measurements over many years.
Making measurements above the atmosphere.
None of the other answers (they are all advantages)

Explanation

Question 15 of 31

1

Satellite observations always have to deal with ❌. One particular example is ❌ coverage (frequency of measurements) versus level of ❌. Typically, a single satellite that provides very ❌ measurements will provide a ❌ level of spatial detail.

Drag and drop to complete the text.

trade-offs

temporal

general

detail

data

frequent

infrequent

low

high

Explanation

Question 16 of 31

1

In the context of atmospheric measurements, the abbreviation "ppmv" means...

Select one of the following:

Parts per million by volume
Parts per mass of volume
Precipitation per mass volume
Particles per mass by volume

Explanation

Question 17 of 31

1

Which of the following cannot (yet) be measured from satellite?

Select one of the following:

Below ground biomass.
Above ground biomass.
mm scale ground surface displacements.
Atmospheric motion (wind).
Sea surface temperature.
Wind direction over the oceans.

Explanation

Question 18 of 31

1

The sky appears blue because atmospheric molecules are ❌ scatterers in the ❌ part of the spectrum. Light at the ❌ end of the spectrum is therefore ❌ significantly more than at the ❌ end, where the light mostly passes through atmosphere.

Drag and drop to complete the text.

Rayleigh

Mie

Optical

Blackbody

visible

infra-red

ultraviolet

microwave

blue

green

yellow

scattered

absorbed

transmitted

red

Explanation

Question 19 of 31

1

Which of the following exhibit signs of "optical scattering" in the visible part of the spectrum?
(There may be more than one correct answer -- click all that apply).

Select one or more of the following:

Polar bear fur.
Milk.
White emulsion paint.
Clouds.
Healthy leaves.
The atmosphere.

Explanation

Question 20 of 31

1

Why are long term (decadal) measurements from satellites difficult, and how is this problem overcome?

Select one of the following:

Satellites don't last more than a few years. The solution is to have a period of overlap in sequential missions to perform an inter-calibration between the sensors.
Satellites don't last more than a few years. The solution is to make sure sequential missions have exactly the same sensor on board.
Satellites typically don't last more than a few years because of fuel constraints. The solution is to increase the lifetime to tens of years by carrying more fuel.
The measurement instruments degrade over time. The solution is to replace the instrument in situ (i.e. in orbit).

Explanation

Question 21 of 31

1

Which of the following might a "passive" remote sensing system measure?
(Select all that apply).

Select one or more of the following:

Emitted radiation from the Earth's surface.
Emitted radiation from the atmosphere.
Solar NIR radiation scattered off the surface of the Earth.
Solar radiation scattered off the atmosphere.
Scattered microwave radiation originating from the remote sensing system.
Scattered NIR radiation originating from the remote sensing system (e.g. a laser).
Solar visible radiation scattered off the surface of the Earth.
Solar radiation after it has passed through the atmosphere.

Explanation

Question 22 of 31

1

Fill the blank spaces to complete the text.

The five different resolutions are: (based on angular resolution of the instrument), (based on pulse size for active instruments), (ability to distinguish in wavelength), (ability to distinguish different brightness levels), (ability to distinguish events in time).

Explanation

Question 23 of 31

1

Which of the following best describes the general term "resolution"?

Select one of the following:

The ability to distinguish (separate) two infinitely narrow signals in some measurement system.
The size (on the ground) of a pixel in an image.
The area (on the ground) of a pixel in an image.
The ability to distinguish (separate) two point targets on the ground.

Explanation

Question 24 of 31

1

When a blackbody warms up, it will emit radiation with ❌ total energy and with a ❌ that will go from ❌ wavelengths to ❌ wavelengths.

Drag and drop to complete the text.

more

less

equal

longer

shorter

peak

minimum

shape

Explanation

Question 25 of 31

1

The Earth's greenhouse effect is mostly driven by which gas?

Select one of the following:

Water vapour
Carbon dioxide
Methane
Nitrogen gas
Oxygen

Explanation

Question 26 of 31

1

1) What frequency of EM radiation corresponds to a wavelength of a) 600nm, and b) 3cm?

Select one of the following:

(a) 500 THz and (b) 10 GHz
(a) 50 THz and (b) 10 GHz
(a) 500 THz and (b) 1 GHz
(a) 500 GHz and (b) 10 GHz
(a) 500 THz and (b) 10 THz

Explanation

Question 27 of 31

1

Domestic electricity supply is at a frequency of 50Hz. What wavelength of electromagnetic radiation would you expect as a result of this oscillating electric field?

Select one of the following:

6000km
3000km
600km
60km
6m

Explanation

Question 28 of 31

1

Use Wein’s Law for this question (find this on the NLN tutorials or a source of your choice). If you heat an iron bar in a furnace, at what temperature would the rod be at to have a peak in its radiance curve in the middle of the visible range (about 550nm)?

Select one of the following:

T= 5269 K
T= 527 K
T= 527 ˚C
T= 5269˚C

Explanation

Question 29 of 31

1

Use Wein’s Law for this question (find this on the NLN tutorials or a source of your choice). If you have an iron bar at the ambient room temperature (say about 20°C) what frequency and wavelength would the maximum be? In what region of the EM spectrum is this?

Select one of the following:

10µm or 30 THz. Thermal IR.
10µm or 10 THz. Thermal IR.
30µm or 10 THz. Thermal IR.
1µm or 100 THz. Near IR.
1µm or 30 THz. Near IR.

Explanation

Question 30 of 31

1

If a satellite has an inclination angle of 98° it will pass the equator on the ascending pass with a bearing of ❌.
At its closest pass to the poles, its bearing will be ❌?
(Note, bearings are relative to North).

Drag and drop to complete the text.

352˚

8˚

90˚

270˚

188˚

172˚

Explanation

Question 31 of 31

1

An EO satellite has an inclination angle of 98° and is orbiting at an altitude of 800km.
The orbital period is ❌. If the swath width is 100km, the shortest time this satellite could conceivably provide global coverage is approximately ❌. The instrument measurements ❌ cover the polar regions.

Drag and drop to complete the text.

101mins

90 mins

3 hours

120 mins

28 days

22 days

28 hours

280 days

do not

do

	Created by Iain Woodhouse over 8 years ago

First class quiz for Remote Sensing of Global Change, an honours module in the School of GeoSciences, Edinburgh University.

Fundamentals of remote sensing

Fundamentals of remote sensing

Question 1 of 31

Which of the following would NOT normally be considered as a form of remote sensing?

Select one of the following:

Explanation

Question 2 of 31

Electromagnetic radiation can be described completely using wavelength, wave velocity, frequency and amplitude?

Select one of the following:

Explanation

Question 3 of 31

Label all the key points in this diagram of the temperature profile through the atmosphere. You need to name the zones defined by the temperature changes, the boundaries between them and also label the altitude axis (approximately)

Drag an answer into the correct orange point.

Explanation

Question 4 of 31

Label the different regions of the electromagnetic spectrum.

Drag an answer into the correct orange point.

Explanation

Question 5 of 31

Label this EM Spectrum with the typical processes that emits radiation of that approximate wavelength.

Drag an answer into the correct orange point.

Explanation

Question 6 of 31

Electromagnetic radiation can be created when... (note: there may be more than one answer)

Select one or more of the following:

Explanation

Question 7 of 31

Which of the following best describes why a "blackbody" is black?

Select one of the following:

Explanation

Question 8 of 31

Which of the following statements is NOT true?

Select one of the following:

Explanation

Question 9 of 31

The albedo of Earth is the fraction of incident sunlight...

Select one of the following:

Explanation

Question 10 of 31

If a represents Earth’s albedo and P is the total power of sunlight incident on Earth, then the power radiated by Earth to space is approximately...

Select one of the following:

Explanation

Question 11 of 31

An object will appear red to the naked eye if...

Select one of the following:

Explanation

Question 12 of 31

An object will appear white to the naked eye if... (Note: more than one answer may be correct).

Select one or more of the following:

Explanation

Question 13 of 31

Approximately what proportion of the mass of the Earth's atmosphere lies within the Troposphere?

Select one of the following:

Explanation

Question 14 of 31

Which of the following in NOT an advantages of satellite measurements?

Select one of the following:

Explanation

Question 15 of 31

Satellite observations always have to deal with ❌. One particular example is ❌ coverage (frequency of measurements) versus level of ❌. Typically, a single satellite that provides very ❌ measurements will provide a ❌ level of spatial detail.

Drag and drop to complete the text.

Explanation

Question 16 of 31

In the context of atmospheric measurements, the abbreviation "ppmv" means...

Select one of the following:

Explanation

Question 17 of 31

Which of the following cannot (yet) be measured from satellite?

Select one of the following:

Explanation

Question 18 of 31

The sky appears blue because atmospheric molecules are ❌ scatterers in the ❌ part of the spectrum. Light at the ❌ end of the spectrum is therefore ❌ significantly more than at the ❌ end, where the light mostly passes through atmosphere.

Drag and drop to complete the text.

Explanation

Question 19 of 31

Which of the following exhibit signs of "optical scattering" in the visible part of the spectrum? (There may be more than one correct answer -- click all that apply).

Select one or more of the following:

Explanation

Question 20 of 31

An object will appear white to the naked eye if...
(Note: more than one answer may be correct).

Which of the following exhibit signs of "optical scattering" in the visible part of the spectrum?
(There may be more than one correct answer -- click all that apply).

Which of the following might a "passive" remote sensing system measure?
(Select all that apply).

If a satellite has an inclination angle of 98° it will pass the equator on the ascending pass with a bearing of ❌.
At its closest pass to the poles, its bearing will be ❌?
(Note, bearings are relative to North).

An EO satellite has an inclination angle of 98° and is orbiting at an altitude of 800km.
The orbital period is ❌. If the swath width is 100km, the shortest time this satellite could conceivably provide global coverage is approximately ❌. The instrument measurements ❌ cover the polar regions.