Remote Sensing Flashcards
What is ecosystem structure?
The biophysical architecture of an ecosystem.
What is leaf area index (LAI)?
Total one sided green leaf area per unit of ground surface area.
Defined area that interacts with solar radiation and provides remote sensing signal.
What is ecosystem function?
The biological, geochemical and physical processes that occur within an ecosystem.
What are vegetation indices?
Intermediaries in the assessment of biochemical/structural traits.
e.g. biomass, LAI, % cover.
What type of light is absorbed/not absorbed by leaves?
Red and blue light are absorbed
Infrared is not absorbed, meaning its good for remote sensing.
What are the applications of vegetive indices?
- Indications of seasonal variations (phenology)
- Change detection studies (climate)
- Monitoring / mapping vegetation
What is LiDAR used for?
Measuring canopy height
What is Optical RS used for?
Measuring green area index and crop yield
What is Microwave RS used for?
Measuring soil moisture
What do the values of NDVI show?
High = dense vegetation
Negative = Snow
Low = clouds
What is the equation for NDVI?
NDVI = NIR - red / NIR + red
What does enhanced vegetation index (EVI) account for?
Accounts for atmospheric and soil effects.
Increased sensitivity at high biomass levels.
What are negatives of NDVI?
- Saturates over dense vegetation
- Less info than original data
- Can be influenced by atmospheric scattering and soil moisture
- May vary according to species
What do vegetational indices struggle with?
Transferability and when species, site and time differ.
What does terrestrial biosphere modelling do?
Quantifies CO2 exchange with the atmosphere. Future CO2 projections.
