EGS Frank Week 4 Earth Observation Flashcards
Overview P1/3
- (1) There are numerous satellites providing () w. different () & ().
- (2) These collect data in (), w. different () & ().
- (3) Satellites can be distinguished by their ().
- (1) There are numerous satellites providing data w. different specifications & capabilities.
- (2) These collect data in different wavelengths w. different detail & frequency.
- (3) Satellites can be distinguished by their different capabilities.
Overview P2/3
- (4) Satellite instruments collect () in many diff. () from the () to the (), which allows the detection of diff. () w. diff ().
- (5) The number of bands refers to ().
- (6) Whilst the amount of detail present in the figures refers to ().
- (4) Satellite instruments collect light in many diff. wavebands from the short blue wavelength to the long thermal wavelength, which allows the detection of diff. earth surface features w. diff. characteristics.
- (5) The number of bands refers to Spectral Resolution.
- (6) Whilst the amount of detail present in the figures refers to Spatial Resolution.
Overview P3/3
- (7) Satellites also have diff. orbits, such as a () orbit & a () orbit.
- (8) The type of orbit has an influence on the () & the (), as well as the ().
- (9) Satellites can be used to study 1. (), 2. (), & 3. (), as well as 4. (), & 5. ().
- (7) Satellites also have diff. orbits, such as a Polar/Sun-synchronous & a Geostationary orbit.
- (8) The type of orbit has an influence on the Spatial Resolution & the Temporal Resolution, as well as the Coverage.
- (9) Satellites can be used to study 1. Vegetation, 2. Land use & 3. Land Cover, as well as 4. Measure temperature & 5. Detect fires
What is the Spatial Resolution of a satellite sensor:
- Definition
- High Spatial Resolution ():
- Low Spatial Resolution ():
- Defines the abilitity to resolve features depending on their size.
- High Spatial Resolution (30m & better):
Shows great detail, i.e. small no. 1m, e.g. google maps - Low Spatial Resolution (30m & less):
Shows less detail, i.e. high number 1000m, e.g. weather looking @ big cloud formations
What is the Temporal Resolution of a satellite sensor:
- Definition
- Example of High Temporal Resolution
- Example of Low Temporal Resolution
- Refers to how often a satellite instrument crosses over the same point
- 30 minutes
- 1-30 days
What is the spectral resolution of a satellite sensor:
- Definition:
- Example:
(1)
(2)
(3)
(4)
(5)
- Refers to the no. & location of wavebands
- Example:
(1) Ultraviolet (0.1-0.4 um)
(2) Visible (0.4-0.7um
(3) Near Infrared (0.7-1.5um)
(4) Thermal Infrared (1.5-11um)
(5) Microwave (1mm-1cm)
Electromagnetic Spectrum (EMS):
- Remote Sensing uses the () that is () & () from Earth @ () of the EMS
- Blue band & Green band able to detect ()
- Red band able to detect ()
- NIR4:
- Remote Sensing uses the radiant energy that is reflected & emitted from Earth @ various “wavelengths” of the EMS
- Blue band & Green band able to detect sediment in water
- Red band able to detect water bodies in more detail
- Even more contrast, able to detect sediment, water & vegetation better
What are the major orbits used in remote sensing?
- Polar/Sun-synchronous
- Geostationary
Orbits
- A
- O
- I
- C
- S
- T
- A
- Altitude
- Orbital period
- Iclination
- Coverage
- Spatial Resolution
- Temporal Resolution
- Application
Polar/Sun-synchronous Orbit:
- Altitude
- Orbital period
- Inclination
- Coverage
- Spatial Resolution
- Temporal Resolution
- Application
- Low Altitude (200-1500km)
- ~90 min
- ~90 degrees
- Global by successive orbits
- High Spatial Resolution: 1m & better
- Low Temporal Resolution: 1-30 days
- Land Resource Applications
Geostationary Orbit:
- Altitude
- Orbital period
- Inclination
- Coverage
- Spatial Resolution
- Temporal Resolution
- Application
- High Altitude (35,000km)
- 24 Hours
- 0 degrees
- Disk of the Earth
- Low Spatial Resolution: 1000m & less
- High Temporal Resolution: 30 min
- Meterological Applications & can be used as Relay Satellites & to Transmit Data.
Sensor Capabilities P1/5
Terra, Aqua MODIS:
- Spatial Resolution:
- Temporal Resolution:
- Spectral Resolution:
- Orbit Type:
- Possible Applications:
- Spatial Resolution: 250m
- Temporal Resolution: 2x Day AM. PM.
- Spectral Resolution: VIS, NIR, TIR - 35 Channels
- Orbit Type: Polar
- Possible Applications: Global Weather Patterns, Fire, Ice, Dust, Snow, Vegetation (NDVI)
Sensor Capabilities 2/5
Landsat 1, 2, 3 MSS:
- Spatial Resolution:
- Temporal Resolution:
- Spectral Resolution:
- Orbit Type:
- Possible Applications:
- Spatial Resolution: 80m
- Temporal Resolution: 18 days
- Spectral Resolution: VIS, NIR - 4 Channels
- Orbit Type: Polar
- Possible Applications: Land Resource Mapping, Study of long term land coverage change (NDVI)
Sensor Capabilities 3/5
Landsat 4, 5, 6, 7 TM, ETM:
- Spatial Resolution:
- Temporal Resolution:
- Spectral Resolution:
- Orbit Type:
- Possible Applications:
- Spatial Resolution: 30m
- Temporal Resolution: 16 days
- Spectral Resolution: VIS, NIR, TIR - 8 Channels
- Orbit Type: Polar
- Possible Applications: Land Resource Mapping, Study of long term land cover change (NDVI)
Sensor Capabilities 4/5
Landsat 8:
- Spatial Resolution:
- Temporal Resolution:
- Spectral Resolution:
- Orbit Type:
- Possible Applications:
- Spatial Resolution: 30m
- Temporal Resolution: ** 2 x month**
- Spectral Resolution: VIS, NIR, TIR - 8 Channels
- Orbit Type: Polar
- Possible Applications: Land Resource Mapping, Study of long term land cover change (NDVI)
Sensor Capabilities 5/5:
Meteosat:
- Spatial Resolution:
- Temporal Resolution:
- Spectral Resolution:
- Orbit Type:
- Possible Applications:
- Spatial Resolution: 1000m
- Temporal Resolution: 15 min
- Spectral Resolution: VIS, NIR, TIR - 3 channels
- Orbit Type: Geostationary
- Possible Applications: Global Weather Patterns. Europe, US, China, India & Japan produce global coverage.
Wien’s Displacement Law
- States:
- Used to identify:
- Formula:
- Example of Formula:
- () of () is () proportional to ().
- Hotter Object:
- Colder Object:
- States: The radiation peaks are inversely proportional to the temperature.
- Used to identify: wavelength @ which max. emission of radiation occurs (for objects)
- Formula: λmax = 2897/T
- E.g.
Sun = 2897/6000 = 0.5 um (Visible)
& Earth = 2897/288 = 10 um (Thermal) - Wavelength of max. emission is inversely proportional to temperature.
- Hotter Object: shorter wavelenghts
- Colder Object: longer wavelengths
What does NDVI stand for?
Normalized Difference Vegetation Index
NDVI P1/2
- Veg. is characterized by () in () in terms of () & doesn’t () a lot of () or ().
- In (), veg. reflects () radiation/light -> therefore more reflection in () -> utilized to study veg.
- In terms of non-veg = reflect () in ().
- Veg. reflects () & absorbs () -> NDVI
- Veg. is characterized by peaking in green in terms of visible light & doesn’t reflect a lot of red or blue.
- In Near Infrared, veg. reflects more radiation/light -> therefore more reflection in NIR -> utilized to study veg.
- In terms of non-veg. = reflect less in NIR
- Veg reflects NIR & absorbs red light -> NDVI
NDVI P2/2
- Formula:
- Health veg. reflectance =
- Stressed veg. reflectance =
- NDVI allows for the ()
- NDVI collected over long time can allow the () & can be used to study ().
- Formula:
NDVI = NIR - Red/NIR + Red - Healthy veg. reflectance =
1. 50% NIR & 8% Red
2. 0.5 - 0.08/0.5 + 0.08
3. NDVI = 0.72 - Stressed veg. reflectance =
1. 40% NIR & 30% Red
2. 0.4 - 0.3/ 0.4 + 0.3
3. NDVI = 0.14 - NDVI allows for the quantification of the state of veg.
- NDVI collected over long time can allow the detection of anomalies & can be used to study precipiation dymanics.
How do we study fire?
- By detecting the () emitted by the ().
- Sensors like () can detect the () generated by fires & provide information on (), (), & ().
- () -> shows as smoky clouds
- () -> Red fire & blue smoke; much more visible
- By detecting the thermal signature emitted by the flames.
- Sensors like MODIS can detect the heat energy generated by fires & provide information on location, extent & intensity.
- MODIS Visible Bands -> shows as smoky clouds.
- MODIS Thermal Bands -> Red fire & blue smoke; much more visible