CH Remote Sensing & Satellite Imagery

Question 1

What does LiDAR stand for in the context of hydrographic remote sensing?

Accepted Answer

Light Detection And Ranging

Answer

Linear Distance And Range

Answer

Land Imaging Detection And Reconnaissance

Answer

Laser Intensity Detection And Ranging

Question 2

Which type of satellite sensor is most commonly used to measure sea surface temperature (SST) in hydrographic studies?

Accepted Answer

Thermal Infrared (TIR) sensor

Answer

Synthetic Aperture Radar (SAR)

Answer

Multispectral optical sensor

Answer

Photon-counting LiDAR

Question 3

What is the primary advantage of multispectral satellite imagery for shallow water bathymetry?

Accepted Answer

It can penetrate clear, shallow water to map the seafloor using light attenuation

Answer

It operates in all weather conditions including heavy cloud cover

Answer

It can measure depths greater than 200 meters in open ocean

Answer

It requires no ground truth calibration data

Question 4

Synthetic Aperture Radar (SAR) is particularly valuable for hydrographic applications because it can:

Accepted Answer

Detect oil spills, ship wakes, and surface roughness regardless of cloud cover or darkness

Answer

Measure water depth in turbid estuarine conditions

Answer

Accurately measure sea surface temperature in real time

Answer

Map the seafloor in waters deeper than 500 meters

Question 5

The Secchi depth is used in satellite-derived bathymetry primarily to estimate:

Accepted Answer

Water transparency and maximum depth of optical light penetration

Answer

Maximum sonar detection range beneath the vessel

Answer

Tidal range at a coastal survey site

Answer

Depth of the thermocline layer

Question 6

The Normalized Difference Water Index (NDWI) is primarily used in remote sensing to:

Accepted Answer

Distinguish and delineate water bodies from land and vegetation

Answer

Measure salinity concentration gradients in coastal waters

Answer

Calculate significant wave height from radar imagery

Answer

Detect submerged aquatic vegetation density

Question 7

Which orbit type do most hydrographic Earth observation satellites use to achieve consistent global coverage?

Accepted Answer

Sun-synchronous Low Earth Orbit (LEO)

Answer

Geostationary orbit at 35,786 km altitude

Answer

Medium Earth Orbit (MEO) used by GPS satellites

Answer

Highly Elliptical Orbit (HEO)