Climatic geomorphology
15
reduction in the spatial and temporal scales being analysed. For instance, research can be
focused on the analysis of micro-drainage basins and the individual slope segments. During
the last few decades efforts in this analytic field have been important. It constitutes part
of the basic subject matter on geomorphology, and the expected advances in it will give a
better understanding to landform evolution. Today, a variety of erosion rates have already
been reported for different lithologies and climates. These sets of data were compiled by
Saunders and Young (1983) and Goudie (1995). For example, on abrupt glaciated slopes
erosion rates are --- 1-4 mm/yr, slopes in temperate zones erode about 0.01-0.1 mm/yr,
in semiarid regions, --~ 0.1-1 mm/yr, in badlands, --~ 1-10 mm/yr, and in the abrupt slopes
of tropical forests, --- 0.1 - 1 mm/yr.
Field and laboratory research on processes requires use of some of the tools of statistics
for the adequate management of the obtained data. This fact gave rise to quantitative
geomorphology, with pioneering work by the hydrologist R. Horton on the morphometry
of drainage basins (Horton, 1945). The further development of quantitative analysis of
landforms has been controlled by the increasing capacity of computers in data management.
As a consequence of the complexity of geomorphological processes, the use of models
has become common as another important aspect of modem geomorphology. Scaled
models partly reproduce natural processes, such as the use of wind tunnels, fluvial erosion
tanks and other laboratory tests. Other models are the analogue ones, such as the ice
deformation simulations by kaolin analogues, or the mathematical models in which Ahnert
(1987a) and Kirby (in 1994) are among the more outstanding present-day geomorphologists. These two kinds of models may achieve all the complexity of process interaction
(Baker and Twidale, 1991). At the beginning of the 21st century it now appears possible
that mathematical process models iterated successively in supercomputers to simulate
deep geologic time may at last make possible the integration of timeless process models
with timebound landform evolution; something that has not been possible heretofore.
2.5. Structure of climatic geomorphology
On 22-23rd September 1926, in Dtisseldorf, Germany, researchers held a meeting on
landform development in different climatic zones, as well as on morphoclimatic classification (Thorbecke, 1927). The results of that conference constituted the first straightforward and comprehensive approach to climatic geomorphology. For some of the
participants, however, their approach to problem formulation for particular climatic
regions lacked a true morphoclimatic method (Beckinsale and Chorley, 1991).
In about the middle of the 20th century, Btidel (1944, 1948) published works that he
afterwards expanded on and analysed in depth in his book on Climatic Geomorphology
(Biidel, 1977), as well as in some subsequent papers (i.e. Btidel, 1980). In these works,
morphoclimatic zones were defined as an assemblage of landscapes resulting from the
activity of the processes working in the different types of climates. In his paper of 1948, Btidel
differentiated eight different morphoclimatic zones using morphologic and climatic criteria.
These were expanded to 10 in his treatise of 1977, in which mountainous environments were
excluded. This author also proposed the term "climatogenic geomorphology" (Btidel, 1963),
defined as the science of the reconstruction of past climates from the analysis of
ancient working processes and landforms. As pointed out by Bremer (1996),
15
reduction in the spatial and temporal scales being analysed. For instance, research can be
focused on the analysis of micro-drainage basins and the individual slope segments. During
the last few decades efforts in this analytic field have been important. It constitutes part
of the basic subject matter on geomorphology, and the expected advances in it will give a
better understanding to landform evolution. Today, a variety of erosion rates have already
been reported for different lithologies and climates. These sets of data were compiled by
Saunders and Young (1983) and Goudie (1995). For example, on abrupt glaciated slopes
erosion rates are --- 1-4 mm/yr, slopes in temperate zones erode about 0.01-0.1 mm/yr,
in semiarid regions, --~ 0.1-1 mm/yr, in badlands, --~ 1-10 mm/yr, and in the abrupt slopes
of tropical forests, --- 0.1 - 1 mm/yr.
Field and laboratory research on processes requires use of some of the tools of statistics
for the adequate management of the obtained data. This fact gave rise to quantitative
geomorphology, with pioneering work by the hydrologist R. Horton on the morphometry
of drainage basins (Horton, 1945). The further development of quantitative analysis of
landforms has been controlled by the increasing capacity of computers in data management.
As a consequence of the complexity of geomorphological processes, the use of models
has become common as another important aspect of modem geomorphology. Scaled
models partly reproduce natural processes, such as the use of wind tunnels, fluvial erosion
tanks and other laboratory tests. Other models are the analogue ones, such as the ice
deformation simulations by kaolin analogues, or the mathematical models in which Ahnert
(1987a) and Kirby (in 1994) are among the more outstanding present-day geomorphologists. These two kinds of models may achieve all the complexity of process interaction
(Baker and Twidale, 1991). At the beginning of the 21st century it now appears possible
that mathematical process models iterated successively in supercomputers to simulate
deep geologic time may at last make possible the integration of timeless process models
with timebound landform evolution; something that has not been possible heretofore.
2.5. Structure of climatic geomorphology
On 22-23rd September 1926, in Dtisseldorf, Germany, researchers held a meeting on
landform development in different climatic zones, as well as on morphoclimatic classification (Thorbecke, 1927). The results of that conference constituted the first straightforward and comprehensive approach to climatic geomorphology. For some of the
participants, however, their approach to problem formulation for particular climatic
regions lacked a true morphoclimatic method (Beckinsale and Chorley, 1991).
In about the middle of the 20th century, Btidel (1944, 1948) published works that he
afterwards expanded on and analysed in depth in his book on Climatic Geomorphology
(Biidel, 1977), as well as in some subsequent papers (i.e. Btidel, 1980). In these works,
morphoclimatic zones were defined as an assemblage of landscapes resulting from the
activity of the processes working in the different types of climates. In his paper of 1948, Btidel
differentiated eight different morphoclimatic zones using morphologic and climatic criteria.
These were expanded to 10 in his treatise of 1977, in which mountainous environments were
excluded. This author also proposed the term "climatogenic geomorphology" (Btidel, 1963),
defined as the science of the reconstruction of past climates from the analysis of
ancient working processes and landforms. As pointed out by Bremer (1996),