Lecture 12 - Estimating Earth surface properties from remote sensing

Question 1

Why estimate vegetation properties?

Answer 1

1. Inter and intra annual global vegetation monitoring
2. Global biogeochemical, climatic, and hydrological modeling
3. Detecting anthropogenic and climate change
4. Agricultural activities

Question 2

Why are composites better?

Answer 2

One band is hard to distinguish land surface features
Composites provide a clearer picture of the scene

Question 3

What are the 3 vegetation indices?

Answer 3

Normalized Difference vegetation index
Enhanced vegetation index
MERIS Terrestrial Cholrophyll index

Question 4

Benefits of Vegetation indices

Answer 4

Better sensitivity to individual bands
Remove noise that alters the usefulness of data

Question 5

What is soil line?

Answer 5

Linear relationship between NIR and red reflectance of bare soil as characterized by slope and intercept parameters.

Question 6

NDVI Equation and values

Answer 6

NIR - red/NIR + red
NDVI range from -1 to +1
Healthy veg is high NDVI and unhealthy is low NDVI
Snow, water, clouds have 0 value

Question 7

What happens to reflectance in healthy vegetation?

Answer 7

NDVI increases due to higher NIR reflectance and lower red reflectance.

Question 8

NDVI disadvantages

Answer 8

Reduced sensitivity at high biomass or dense vegetation
Any factor that unevenly influences red or NIR reflectance has an influence

Question 9

What does the Soil Adjusted Vegetation Index (SAVI) do and its equation?

Answer 9

Designed to remove the dependency of NDVI on the brightness of canopy background reflectance.
(1+L)(NIR - red)/NIR + red + L