RS Measurement

Question 2

Wavelength

Answer 2

distance between successive peaks or troughs

Question 3

frequency

Answer 3

numbe rof wave cycles passing a certain point per unit of time

Question 4

amplitude

Answer 4

height of a wave, indictaing intensity, from peak to trough

Question 5

Ultraviolet light

Answer 5

shorter wavelengths than visible, 100-400nm

Question 6

visible light

Answer 6

EMR we can see, 400-700nm

Question 7

Near-infrared

Answer 7

just beyond visible red light, 800-2500nm

Question 8

mid (short-wave) infrared

Answer 8

between near and thermal, 1.4 - 3um

Question 9

thermal infrared

Answer 9

all infrared except far IR are wavelengths associated with heat radiation, 1.4 - 15 um

Question 10

microwave

Answer 10

longer than visible, 30cm - 1mm

Question 11

global radiation balance equation

Answer 11

interaction of EMR with earth’s surface, involving absorption, transmission, and reflection

total amount of radiation that strikes an object = reflected, absorbed, and transmitted radiation

Question 12

DN

Answer 12

no unit value of radiometric values in RS data, recorded by sensor

Question 13

how is precision determined for DN

Answer 13

bit depth of a sensor

Question 14

Radiance

Answer 14

Amount of EMR leaving an area per unit of time, area, and angle

physical qunatity represented by sensor as DN

Question 15

Reflectance

Answer 15

ratio of reflected energy over incident energy

Question 16

Spectral signatures

Answer 16

• Characteristic energy
  reflected by and/or
  emitted from an object
  as a function of λ
• Based on physical and
  chemical composition
  of the target

Question 17

water

Answer 17

strong absorbe rof EMR, especially greater than visible wavelengths

IR absorbed quickly, blue is last to be absorbed

Question 18

Water reflectance signature affected by

Answer 18

nature of suspended matter, ,and depth to the bottom

Question 19

snow

Answer 19

highly reflective, absorbs NIR, finer grain size means brighter

Question 20

reflectance signature of snow affected by

Answer 20

water, grain size, degree of freshness

aging = larger grain size = darker

Question 21

minerals

Answer 21

have their own unique spectral signature,s spectral res of satellites too poor to see the details though

Question 22

vegetation reflectance

Answer 22

spectral scattering/absorbing properties of canopy components (leaves, stems, fruits, flowers, etc), and canopy architecture (arrangement, leaf area index, biomass)

Question 23

reflectance spectra of a leaf

Answer 23

chlorophyll absorbs visible and reflects NIR and some SWIR

Question 24

NDVI

Answer 24

normalized difference vegetation index, NIR-red/NIR+red

Question 25

healthier vegetation does what to NIR and NDVI

Answer 25

increases both, red goes down