Relief energy

The Dhaulagiri South Face in the Nepalese Himalayas has the greatest relief energy of the land surface with an altitude difference of 4,622 m

The greatest difference in height in a mountain range is 10,203 m between the summit of Mauna Kea ( Hawaii ) and the deepest, submarine point at the foot of the mountain

As relief energy , relief difference or relative relief is referred to in the geomorphology of the height difference, which in a certain area per surface unit occurs generally in meters (difference) per square kilometer (or other unit area) is specified, or distance-based per kilometer straight line as a height difference . Accordingly, a mountainous landscape has a high relief energy, while a plain has only a low one.

definition

The term goes back to Albrecht Penck  (1894). For the sake of a more precise designation, one speaks today of “relative relief” as an area-related size. The specification in meters per square kilometer is given by Persch and Caine (1984), there are also definitions of a fixed distance (in meters per kilometer), which corresponds to a specific height difference , about 5 km (same authors), Finch and Trewartha ( 1949) gave 10 miles (about 16 km). The second, larger value is more suitable for low-profile low mountain ranges; a distance of 5 kilometers to the foot of the mountain is also not uncommon in the high mountains.

Use in theoretical geometry

The term relief energy was therefore introduced in order to be able to better grasp the height differences in an area regardless of sea level ( absolute height ). Thus, while lying Highlanders (eg the highlands of Tibet ) often at high altitude above sea level, but large areas are relatively flat and have very little relief energy. The Maritime Alps on the Mediterranean Sea, on the other hand, are located at relatively low altitude, but have a large relief energy.

The size is used for the definition of geomorphometric terrain classes:

Relief classification according to Persch & Caine (1984)

Type	Difference in altitude over 5 km	Relative relief (area-related)
High mountain system ( high mountains )	> 1000 m	500 m / km²
Mountain system ( Mountains )	500-1000 m	200 m / km²
Mountainous terrain ( mountains )	100-500 m	100 m / km²
Hilly terrain ( hill country )	50-100 m	50 m / km²

Use in geoscientific practice

Merano (South Tyrol) and its mountains: the difference in altitude between the Etschtal-Grund and the 3000-meter mountain peaks is 2500 m

The IOER-Monitor map clearly shows the different relief energies.

In practice, the relief energy is mainly used to better estimate any soil erosion that may occur . It is not an absolute size, but depends on the special choice of the reference area depending on the question, so it can be determined for a slope as well as for the entire mountain range or a large mountain area.

A moving average is also calculated for a comprehensive display , depending on the fineness for each point in a 10 km radius, with which the topography of entire landscape areas can be displayed. This also provides information about the relief variability (diversity and variety of the morphometric treasure trove of a region), which allows very precise modeling with increasing fine-scale evaluation of digital terrain models , which today are based on satellite-supported laser scan data.

The Monitor of Settlement and Open Space Development (IOER Monitor) offers such a modeling . The relief energy or the relative relief is shown here throughout Germany. In this way, the physical structure of the country can be traced, since the difference between the maximum and minimum height value for each area is determined on the basis of the digital terrain model (DGM 10). The figure clearly shows the low mountain range regions in central and southern Germany as well as the Alpine foothills on the border with Switzerland and Austria. The extent to which the territorial units are shaped by the relief is mainly visible through the effect of rivers or river inflows. The relief-creating effect is particularly evident on the Danube and its tributaries in the Alpine foothills.

literature

• Albert Schläpfer: The calculation of the relief energy and its meaning as a graphic representation. Diss. Thesis-Zürich, Huber, Zürich 1938, OCLC 2801061

Web links

• A. Burak, H. Zepp and L. Zöller: Reliefenergy - where the differences in altitude are greatest , National Atlas Federal Republic of Germany - Relief, soil and water (PDF file)

Individual evidence

1. ↑ ^{a b} Stefan Rasemann: Geomorphometric structure of a mesoscale alpine geosystem . Dissertation Rheinische Friedrich-Wilhelms-Universität Bonn. Bonn 2003, 2.1.2 Definition and demarcation of the high mountains: Relatives Relief , p. 17th f . ( pdf , hss.ulb.uni-bonn.de [accessed on February 10, 2017]).
2. ^ Albrecht Penck: Morphology of the Earth's Surface. Engelhorn, Stuttgart 1894, p. OA
3. ^ ^{A b} D. Barsch, N. Caine: The nature of mountain geomorphology. In: Mountain Research and Development 4, 1984, pp. 287-298 (reference p. OA).
4. ↑ VC Finch, GT Trewartha: Physical Elements of Geography. McGraw-Hill, New York 1949, p. OA
5. ↑ an application of ecology, see for example Reliefvariableness , Ministry for Economy, Climate Protection, Energy and State Planning Rhineland-Palatinate, wald-rlp.de
6. ^ [1] IOER monitor. Retrieved November 10, 2016.