Tropical climates - The Global Climate System: Patterns, Processes, and Teleconnections - page 81

applications, thus their use is much less than that of sensors using the
0.4-12.5 mm wavelengths. A few Earth resources radar satellites exist and
collectively they have spatial resolutions from 3 m to 38 þ km that use many
parts of the microwave spectrum (L, S, C, X, K, Q, W bands with wavelengths
> 30 cm to < 1 cm respectively). Most radar systems used for LULC research
have high or medium spatial resolution in the 10-100 m range (e.g. ERS
series, Radarsat series). Low spatial resolution satellite radar sensors also
exist with spatial resolutions most typically from 4 km to 38 km (e.g. TRMM/
TMI). Technical specifications and uses of major satellite sensors that collect
electromagnetic energy (visible, infrared, and microwave) can be found at the
NASA website: geo.arc.nasa.gov/sge/health/sensor/cfsensor.html.
High-resolution sensors provide detail that can acquire information
about parts of an individual tree. Medium-resolution sensors provide data to
develop information about LULC features at a subregional scale. Low-
resolution sensors are used to develop information about Earth surface
features at a regional scale, and most of the very low-resolution sensors are
used to acquire continental and global scale data that are frequently focused
on atmospheric phenomena (e.g. gases, pollutants, clouds) and other large
Earth surface features (e.g. oceans, ice). Meteorologists, climatologists, and
oceanographers are the biggest users of very low-resolution spectral data.
Land use/land cover (LULC) and biomass changes in Amazonia
Road building, political incentives/programs, and commercial developments,
that began in the late 1960s and 1970s, started to change Amazonia (Moran
1981 ). Moist mature forests were cut and/or burned in large quantities,
particularly near the roads that supported movement of goods and people
(Moran 1981 ). Almost one-ninth of Amazonia was deforested by 1988 (Skole
and Tucker 1993 ), but the exact percentage that currently has been deforested
varies from authority to authority due to different definitions of the original
mature forest base and deforestation statistics. Common recent estimates of
Brazilian Amazonia deforestation range from 12% to 18%. Deforestation
from 1988 to the present averages approximately 0.45% annually according
to Brazil's official National Institute for Space Research (INPE) figures from
the 2004 website (rainforests.mongabay.com/amazon/2004_deforestation.html).
This deforestation has converted large areas of mature forest into a mosaic of
patches of agricultural lands, pasture, and different stages of forest succes-
sion, with about 20-50% of the deforested area in different succession stages
(Lucas et al. 2000 ).
Tropical moist mature forests have accumulated large amounts of biomass.
Removal of these forests to make way for alternate land uses initially results
in large quantities of CO 2 release to the atmosphere through burning and
decomposition. The most common initial land use following deforestation is