REMOTE SENSING OF THE ENVIRONMENT

MIDTERM March 15, 2001, Geography 4093/5093

You can choose 6 question to answer out of 9. You cannot choose partial questions (e.g., 2a,b & 3c). You have to answer question 9. Please indicate at the end of the exam the question numbers you have not selected.

1. Electromagnetic Radiation (EMR)

a) define the properties of a black body and of a gray body.

b) plot the spectral radiant emittance (Wm^-2 mm^-1) versus wavelengths for the sun and the earth (graph).

c) what is an atmospheric window in terms of thermal infrared radiation, describe the phenomena?

2. Radiative Properties

a) define albedo for the visible EMR and emissivity for the thermal EMR.

b) what are the three principle interactions of EMR with the surface.

c) give example of polarized and non-polarized EMR.

3. Atmospheric Effects

a) why is microwave radiation at 10 GHz not affected by clouds?

b) the intensity of Rayleigh scattering (molecular scattering) is proportional to what?

c) what is non-selective scattering; give examples.

4. Film and filters

a) name three types of aerial films and discuss their difference.

b) rank the above film types regarding their ability to penetrate atmospheric haze.

c) discuss means to enhance tonal contrast (reduction of atmospheric haze) for black and white films.

5. Satellite Platforms and Orbits

a) discuss the advantages of satellite platforms versus aircraft platforms in remote sensing applications.

b) what is the main difference between a geostationary and sun-synchronous orbit, and what are their typical heights above the earth surface?

c) describe and discuss the difference between environmental and meteorological satellites.

6. Landsat, ETM, TM, MSS

a) what does the acronym TM stand for?

b) what are the different IFOV’ for the different sensors ETM, TM, and MSS (size of pixel)?

c) what is the orbit of the Landsat satellite?

7. Passive Microwave (PM) and Optical Sensors (VIS)

a) ground resolution of space-borne passive microwave instruments is much coarser than of visible sensors – why?

b) give examples of space borne sensors for passive microwave and visible spectral range.

c) which of the two sensors (VIS and PM) can penetrate clouds and explain why?

8. RADAR and LIDAR

a) compare the RADAR backscatter signal strength of a dry snow surface versus a lava field.

b) what is the typical ground resolution of a space-borne SAR?

c) describe slant range distortion, layover and shadowing for SAR imagery

9. Applications

The United Nations (UN) gave you a research grant US$ 5,000 to monitor the snow cover distribution for the Himalayas for one year. What kind of satellite imagery and spectral bands would you chose? Due to your good performance during that first project year, the UN provides unlimited funding for your second and third year of the project. What kind of sensors/satellites would you chose and describe your approach (spatial and temporal coverage, spectral ranges)?