Title: GGR315
Tags: TBA

Q: Speed of Light
A: 3 * 10^8 m/s

Q: Steffan-Boltzmann equation
A: W = \(\sigma T^4\)
W: total emitted radiation energy (as watt m^-2)
\(\sigma\) is the SB constant
T: in K
greybodies: * \(\epsilon\) (emissivity)
for blackbodies
hot bodies emit more energy per unit area than cold

Q: Wien's Law
A: wavelength in \(\upmu m\) where radiance is max
as objects become hotter, wavelength of max emittance shifts to shorter wavelengths
\(\uplambda_{max}\) = 2897.8 / T

Q: Remote sensing (define)
A: Science and art of deriving information about an object without touching it, or: the practice of deriving information about the earth’s land and water surfaces using images acquired from an overhead perspective, using electromagnetic radiation in one or more regions of the electromagnetic spectrum, reflected or emitted from the earth’s surface.

Q: Temporal resolution
A: imaging revisit interval (eg every 16 days)

Q: Spatial resolution
A: Pixels: sensor limitation to size of smallest ground area that can be separately recorded on an image (eg 10x10 m)

Q: Radiometric resolution
A: Ability of a remote sensing system to record many levels of values
(7, 8, 9, 10-bit...)

Q: Land resource satellite images
A: AVHRR, Landsat, ERS/ Radarsat, IKONOS

Q: Digital Number
A: the value of pixels
representing intensity (magnitude) of electromagnetic energy
+ve binary digits (8-bit image = 2^8=256, so 0-255 color levels)

Grey level

Q: Wavelength vs frequency
A: are inversely related
c = \(\uplambda\)v
where
- c = speed of light
- \(\uplambda\) = wavelength
- v = frequency

Q: u: Radiant energy
A: Total radiation energy (J)

Q: u: Radiant energy flux
A: radiant energy per unit time
J/sec = W

Q: u: Radiant flux density
A: radiant flux per unit surface area
J(m^2 * s) = W/m^2

Q: Irradiance
A: radiant flux density: fluxes to/ from a flat surface in all directions
(same units: J/ m^2 * s)

Q: u: Spectral irradiance
A: irradiance per unit wavelength
J/(m^2 * s * \(\upmu\)m)

Q: Reflec{tance,ivity}
A: Reflected irradiance / Total incoming irradiance
is unitless

Q: Absorp{tance,tivity}
A: absorbed irradiance / total incoming irradiance
unitless

Q: Transm{ittance,issivity}
A: transmitted irradiance / total incoming irradiance
unitless

Q: Radiation conservation law
A: absorption + reflection + transmission = incoming radiation

Q: Plank's law (what)
A: distribution of emitted radiant energy for different wavelengths
higher energy, higher emits
higher temp, lower wavelengths when peak ocurrs
radiation (wavelength?) emitted by blackbody at a certain temperature

Q: ES: Visible light spectrum colors
A: 400-700nm
Violet, Blue, Green, Yellow, Orange, Red

Q: ES: Ordering
A: Gamma Rays, X-rays, UV, Visible, Infrared, Microwave, Radio

Q: ES: Gamma rays
A: - 0.03 nm

Q: ES: X-rays
A: 0.03 nm - 300 nm

Q: ES: UV
A: 300 nm - 380 nm

Q: ES: Infrared
A: 720 nm - 15.0 \(\upmu m\)

Q: ES: Microwave
A: 15.0 \(\upmu m\) - 30 cm

Q: ES: Radio
A: 30 cm -

Q: kelvin, celcius
A: k = 273.15 + c

Q: Emmisivity
A: \(\epsilon = M/M_b\)
emmited irradiance of a given object / emitted irradiance of a blackbody
ratio, at the same temperature
measure of effectiveness of an object as a radiator of electromagnetic energy

Q: What does scattering do?
A: Decreases quality of an image

Q: Rayleigh
A: Specks of dust, N_2, O_2 molecules
Strongly wavelength dependent

Q: Mie
A: Dust, pollen, smoke, water droplets
Weakly wavelength dependent

Q: Nonselective
A: Large water droplets, large particles of airborne dust
Wavelength independent

Q: atmospheric absorption
A: absorption of radiation occurs when atmosphere prevents transmission of radiation (or its energy) through atmosphere

Q: absorption causing gases
A: ozone (O_3)
carbon dioxide (CO_2)
Water vapour (H_2O)

Q: atmospheric windows
A: UV and visible
near infrared
mid-infrared
Thermal IR
Microwave

Q: Radiance < - > Irradiance
A: I: radiant flux density: Jm^-2s^-1
R: radiant flux density per unit sold angle Jm^-2 s^-1 sr^-1
For a diffuse reflector (Lambertian surface): I = \(\pi R\)

Q: Selective, non-selective transmitters
A: non-selective: same colour

Q: active sensor
A: generates, emits radiation to the surface, receive the returned signals
inc. active microwave (RADAR), Laser, ...

Q: passive sensors
A: receive reflected or emitted signals from the surface, inc.
optical, thermal, and passive microwave sensors

Q: LANDSAT: Band 1 (Blue-Green)
A: - soil/vegetation distinction
- cultural/urban feature ID
- penetration of clear water

Q: LANDSAT: Band 2 (Green)
A: - green vegetation
- cultural/urban feature ID
- reflectance from turbid water

Q: LANDSAT: Band 3 (Red)
A: - Plant chlorophyll absorption
- Cultural/ urban feature ID

Q: LANDSAT: Band 4 (Near-Infrared)
A: - ID plant/ vegetation types, health, biomass content
- Water body delineation
- Soil moisture

Q: LANDSAT: Band 5 (Mid-Infrared)
A: - Sensitive to moisture in soil and vegetation
- Discriminationg snow/ cloud-covered areas
- Penetration of thin clouds

Q: LANDSAT: Band 6 (Far-Infrared)
A: - Relative brightness temperature
- Vegetation stress and soil moisture discrimination related to thermal radiation
- Thermal mapping (urban, water)

Q: LANDSAT: Band 7 (Mid-Infrared)
A: - Discrimination of mineral and rock types
- Hydroxyl ion absorption
- Sensitive to vegetation moisture content