Geoscience Reference
In-Depth Information
forest trees are important regulators of hydrological processes, especially those
involving groundwater hydrology and local evaporation and rainfall/snowfall
patterns.
These and other features of the forest ecosystems and large areas occupied by
them demand the use of coupled mathematical models to study the forest in their
evolution. This chapter gives examples of such models and remote sensing tech-
nologies. In the future it is necessary to develop the proposed approaches mainly
based on the GIMS technology. Such approach gives the possibility to study the
structure of forest ecosystems in vertical and horizontal dimensions. The horizontal
structure is usually described by how individual trees, shrubs, herbs, and openings
or gaps are distributed. The vertical structure has several levels and its study using
remote sensing means is possible provided that there are data about microwave
radiation attenuation in the canopy.
Parallel with microwave monitoring of vegetation covers, optical sensors located
on
flying laboratory and satellites deliver spectral images of land covers with high
spatial resolution. In this case, the classi
fl
cation of land covers is based on the
difference of their spectral re
ectance (Figs.
8.30
and
8.31
). Moreover, spectral
image recognition method described in Chap.
9
can be used for the land cover
classi
fl
cations.
Vegetation indices are widely used to assess qualitatively the biophysical and
morphological characteristics of vegetation from remote sensing measurements.
Sensitivity of each vegetation index to different vegetation characteristics covers
restricted parametrical cluster of the atmosphere-soil-plant system. Different satel-
lites deliver data for global and regional vegetation index imagery at various pixel
size resolutions. The sites include boreal forests, temperate coniferous forests
temperate deciduous forests, tropical rainforests, grasslands, savannas, and desert
biomes. Differences and similarities in sensitivity to vegetation conditions are
Fig. 8.30 Spectral re
fl
ectance of the land covers in the red, near infrared and short wave infrared
bands.
http://commons.wikimedia.org/wiki/File:Incoming_spectral_re
fl
ectance_from_different_
objects_to_a_sensor_system.svg
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