Physical geography

True-color image of the Earth's surface and atmosphere. NASA Goddard Space Flight Center image.

Physical geography (also known as geosystems or physiography) is one of the two major subfields of geography^[1]. Physical geography is that branch of natural science which deals with the study of processes and patterns in the natural environment like atmosphere, biosphere and geosphere, as opposed to the cultural or built environment, the domain of human geography.

Within the body of physical geography, the Earth is often split either into several spheres or environments, the main spheres being the atmosphere, biosphere, cryosphere, geosphere, hydrosphere, lithosphere and pedosphere. Research in physical geography is often interdisciplinary and uses the systems approach.

Sub-fields

A natural arch.

Physical Geography can be divided into several sub-fields, as follows:

• Geomorphology is the science concerned with understanding the surface of the Earth and the processes by which it is shaped, both at the present as well as in the past. Geomorphology as a field has several sub-fields that deal with the specific landforms of various environments e.g. desert geomorphology and fluvial geomorphology, however, these sub-fields are united by the core processes which cause them; mainly tectonic or climatic processes. Geomorphology seeks to understand landform history and dynamics, and predict future changes through a combination of field observation, physical experiment, and numerical modeling (Geomorphometry). Early studies in geomorphology are the foundation for pedology, one of two main branches of soil science.

Meander formation.

• Hydrology is predominantly concerned with the amounts and quality of water moving and accumulating on the land surface and in the soils and rocks near the surface and is typified by the hydrological cycle. Thus the field encompasses water in rivers, lakes, aquifers and to an extent glaciers, in which the field examines the process and dynamics involved in these bodies of water. Hydrology has historically had an important connection with engineering and has thus developed a largely quantitative method in its research; however, it does have an earth science side that embraces the systems approach. Similar to most fields of physical geography it has sub-fields that examine the specific bodies of water or their interaction with other spheres e.g. limnology and ecohydrology.

Alpine glacier.

• Glaciology is the study of glaciers and ice sheets, or more commonly the cryosphere or ice and phenomena that involve ice. Glaciology groups the latter (ice sheets) as continental glaciers and the former (glaciers) as alpine glaciers. Although, research in the areas are similar with research undertaken into both the dynamics of ice sheets and glaciers the former tends to be concerned with the interaction of ice sheets with the present climate and the latter with the impact of glaciers on the landscape. Glaciology also has a vast array of sub-fields examining the factors and processes involved in ice sheets and glaciers e.g. snow hydrology and glacial geology.

Wallace line.

• Biogeography is the science which deals with geographic patterns of species distribution and the processes that result in these patterns. Biogeography emerged as a field of study as a result of the work of Alfred Russel Wallace, although the field prior to the late twentieth century had largely been viewed as historic in its outlook and descriptive in its approach. The main stimulus for the field since its founding has been that of evolution, plate tectonics and the theory of island biogeography. The field can largely be divided into five sub-fields: island biogeography, paleobiogeography, phylogeography, zoogeography and phytogeography

Climate trends.

• Climatology is the study of the climate, scientifically defined as weather conditions averaged over a long period of time. It differs from meteorology, which studies atmospheric processes over a shorter duration, which are then examined by climatologists to find trends and frequencies in weather patterns/phenomena. Climatology examines both the nature of micro (local) and macro (global) climates and the natural and anthropogenic influences on them. The field is also sub-divided largely into the climates of various regions and the study of specific phenomena or time periods e.g. tropical cyclone rainfall climatology and paleoclimatology.

Nitrogen cycle.

• Pedology is the study of soils in their natural environment. It is one of two main branches of soil science, the other being edaphology. Pedology mainly deals with pedogenesis, soil morphology, soil classification. In physical geography pedology is largely studied due to the numerous interactions between climate (water, air, temperature), soil life (micro-organisms, plants, animals), the mineral materials within soils (biogeochemical cycles) and its position and effects on the landscape such as laterization.

• Palaeogeography is the study of the distribution of the continents through geologic time through examining the preserved material in the stratigraphic record. Palaeogeography is a cross-discipline, almost all the evidence for the positions of the continents comes from geology in the form of fossils or geophysics the use of this data has resulted in evidence for continental drift, plate tectonics and supercontinents this in turn has supported palaeogeographic theories such as the Wilson cycle.

High-energy coastline.

• Coastal geography is the study of the dynamic interface between the ocean and the land, incorporating both the physical geography (i.e coastal geomorphology, geology and oceanography) and the human geography of the coast. It involves an understanding of coastal weathering processes, particularly wave action, sediment movement and weathering, and also the ways in which humans interact with the coast. Coastal geography although predominantly geomorphological in its research is not just concerned with coastal landforms, but also the causes and influences of sea level change.

Thermohaline circulation.

• Oceanography is the branch of physical geography that studies the Earth's oceans and seas. It covers a wide range of topics, including marine organisms and ecosystem dynamics (biological oceanography); ocean currents, waves, and geophysical fluid dynamics (physical oceanography); plate tectonics and the geology of the sea floor (geological oceanography); and fluxes of various chemical substances and physical properties within the ocean and across its boundaries (chemical oceanography). These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within it.

• Quaternary science is an inter-disciplinary field of study focusing on the Quaternary period, which encompasses the last 2.6 million years. The field studies the last ice age and the recent interstadial the Holocene and uses proxy evidence to reconstruct the past environments during this period to infer the climatic and environmental changes that have occurred.

Habitat fragmentation.

• Landscape ecology is a sub-discipline of ecology and geography that address how spatial variation in the landscape affects ecological processes such as the distribution and flow of energy, materials and individuals in the environment (which, in turn, may influence the distribution of landscape "elements" themselves such as hedgerows). The field was largely founded by the German geographer Carl Troll Landscape ecology typically deals with problems in an applied and holistic context. The main difference between biogeography and landscape ecology is that the latter is concerned with how flows or energy and material are changed and their impacts on the landscape whereas the former is concerned with the spatial patterns of species and chemical cycles.

Digital elevation model.

• Geomatics is the field of gathering, storing, processing, and delivering of geographic information, or spatially referenced information. Geomatics includes geodesy (scientific discipline that deals with the measurement and representation of the earth, its gravitational field, and other geodynamic phenomena, such as crustal motion, oceanic tides, and polar motion) and G.I.S. (a system for capturing, storing, analyzing and managing data and associated attributes which are spatially referenced to the earth) and remote sensing (the short or large-scale acquisition of information of an object or phenomenon, by the use of either recording or real-time sensing devices that are not in physical or intimate contact with the object).

Salinization.

• Environmental geography is a branch of geography that analyzes the spatial aspects of interactions between humans and the natural world. The branch bridges the divide between human and physical geography and thus requires an understanding of the dynamics of geology, meteorology, hydrology, biogeography, and geomorphology, as well as the ways in which human societies conceptualize the environment. Although the branch was previously more visible in research than at present with theories such as environmental determinism linking society with the environment. It has largely become the domain of the study of environmental management or anthropogenic influences on the environment and vice a versa.

Journals and literature

Physical geography and Earth Science journals communicate and document the results of research carried out in universities and various other research institutions. Most journals cover a specific field and publish the research within that field, however unlike human geographers, physical geographers tend to publish in inter-disciplinary journals rather than predominantly geography journal; the research is normally expressed in the form of a scientific paper. Additionally, textbooks, books, and magazines on geography communicate research to laypeople, although these tend to focus on environmental issues or cultural dilemmas. Examples of journals that publish articles from physical geographers are:

Historical evolution of the discipline

From the birth of geography as a science during the Greek classical period and until the late nineteenth century with the birth of anthropogeography or Human Geography, Geography was almost exclusively a natural science: the study of location and descriptive gazetteer of all places of the known world. Several works among the best known during this long period could be cited as an example, from Strabo (Geography), Eratosthenes (Geography) or Dionisio Periegetes (Periegesis Oiceumene) in the Ancient Age to the Alexander von Humboldt (Cosmos) in the century XIX, in which geography is regarded as a physical and natural science, of course, through the work Summa de Geografía of Martín Fernández de Enciso from the early sixteenth century, which is indicated for the first time the New World.

During the eighteenth and nineteenth centuries, a controversy exported from Geology, between supporters of James Hutton (uniformitarianism Thesis) and Georges Cuvier (catastrophism) strongly influenced the field of geography, because geography at this time was a natural science since Human Geography or Antropogeography had just developed as a discipline in the late nineteenth century.

Two historical events during the nineteenth century had a great effect in the further development of physical geography. The first was the European colonial expansion in Asia, Africa, Australia and even America in search of raw materials required by industries during the Industrial Revolution. This fostered the creation of geography departments in the universities of the colonial powers and the birth and development of national geographical societies, thus giving rise to the process identified by Horacio Capel as the institutionalization of geography.

One of the most prolific empires in this regard was the Russian. A mid-eighteenth century many geographers are sent by the Russian altamirazgo different opportunities to perform geographical surveys in the area of Arctic Siberia. Among these is who is considered the patriarch of Russian geography: Mikhail Lomonosov who in the mid-1750s began working in the Department of Geography, Academy of Sciences to conduct research in Siberia, their contributions are notable in this regard, shows the soil organic origin, develops a comprehensive law on the movement of the ice that still governs the basics, thereby founding a new branch of Geography: Glaciology. In 1755 his initiative was founded Moscow University where he promotes the study of geography and the training of geographers. In 1758 he was appointed director of the Department of Geography, Academy of Sciences, a post from which would develop a working methodology for geographical survey guided by the most important long expeditions and geographical studies in Russia. Thus followed the line of Lomonosov and the contributions of the Russian school became more frequent through his disciples, and in the nineteenth century we have great geographers as Vasily Dokuchaev who performed works of great importance as a "principle of comprehensive analysis of the territory" and "Russian Chernozem" latter being the most important where introduces the geographical concept of soil, as distinct from a simple geological strata, and thus founding a new geographic area of study: the Pedology. Climatology also receive a strong boost from the Russian school by Wladimir Köppen whose main contribution, climate classification, is still valid today. However, this great geographer also contributed to the Paleogeography through his work "The climates of the geological past" which is considered the father of Paleoclimatology. Russian geographers who made great contributions to the discipline in this period were: NM Sibirtsev, Pyotr Semyonov, K. D. Glinka, Neustrayev, among others.

The second important process is the theory of evolution by Darwin in mid-century (which decisively influenced the work of Ratzel, who had academic training as a zoologist and was a follower of Darwin's ideas) which meant an important impetus in the development of Biogeography.

Another major event in the late nineteenth and early twentieth century will give a major boost to development of geography and will take place in United States. It is the work of the famous geographer William Morris Davis who not only made important contributions to the establishment of discipline in his country, but revolutionized the field to develop geographical cycle theory which he proposed as a paradigm for Geography in general, although in actually served as a paradigm for Physical Geography. His theory explained that mountains and other landforms are shaped by the influence of a number of factors that are manifested in the geographical cycle. He explained that the cycle begins with the lifting of the relief by geological processes (faults, volcanism, tectonic upheaval, etc.).. Geographical factors such as rivers and runoff begins to create the V-shaped valleys between the mountains (the stage called "youth"). During this first stage, the terrain is steeper and more irregular. Over time, the currents can carve wider valleys ( "maturity") and then start to wind, towering hills only ( "senescence"). Finally, everything comes to what is a plain flat plain at the lowest elevation possible (called "baseline") This plain was called by Davis' "peneplain" meaning "almost plain" Then the rejuvenation occurs and there is another mountain lift and the cycle continues. Although Davis's theory is not entirely accurate, it was absolutely revolutionary and unique in its time and helped to modernize and create Geography subfield of Geomorphology. Its implications prompted a myriad of research in various branches of Physical Geography. In the case of the Paleogeography this theory provided a model for understanding the evolution of the landscape. For Hydrology, Glaciology and Climatology as a boost investigated as studying geographic factors shape the landscape and affect the cycle. The bulk of the work of William Morris Davis led to the development of a new branch of Physical Geography: Geomorphology whose contents until then did not differ from the rest of Geography. Shortly after this branch would present a major development. Some of his disciples made significant contributions to various branches of physical geography such as Curtis Marbut and his invaluable legacy for Pedology, Mark Jefferson, Isaiah Bowman, among others.

Notable physical geographers

Alexander Von Humboldt, considered to be the founding father of physical geography.

• Eratosthenes (276 – 194 BC), who made the first known reliable estimation of the Earth's size.^[2] He is considered the father of geodesy.^[2][3]
• Ptolemy (c.90 – c.168), who compiled Greek and Roman knowledge to produce the book Geographia.
• Abū Rayhān Bīrūnī (973 – 1048 AD), considered te father of geodesy.^[4][5]
• Ibn Sina (Avicenna, 980–1037), who formulated the law of superposition and concept of uniformitarianism in The Book of Healing.
• Muhammad al-Idrisi (Dreses, 1100 – c.1165), who drew the Tabula Rogeriana, the most accurate world map in pre-modern times.^[6]
• Piri Reis (1465 – c.1554), whose Piri Reis map is the oldest surviving world map to include the Americas and possibly Antarctica
• Gerardus Mercator (1512–1594), an innovative cartographer and originator of the Mercator projection.
• Bernhardus Varenius (1622–1650), Wrote his important work "General Geography" (1650), first overview of the geography, the foundation of modern geography.
• Mikhail Lomonosov (1711–1765), father of Russian geography and founded the study of glaciology.
• Alexander Von Humboldt (1769–1859), considered the father of modern geography. Published Kosmos and founded the study of biogeography.
• Arnold Henry Guyot (1807–1884), who noted the structure of glaciers and advanced the understanding of glacial motion, especially in fast ice flow.
• Louis Agassiz (1807–1873), the author of a glacial theory which disputed the notion of a steady-cooling Earth.
• Alfred Russel Wallace (1823–1913), founder of modern biogeography and the Wallace line.
• Vasily Dokuchaev (1840–1903), patriach of russian geography and founder of pedology.
• Wladimir Peter Köppen (1846–1940), developer of most impotant climate classification and founder of Paleoclimatology.
• William Morris Davis (1850–1934), father of American geography, founder of Geomorphology and developer of the geographical cycle theory.
• Walther Penck (1888–1923), proponent of the cycle of erosion and the simultaneous occurrence of uplift and denudation.
• Sir Ernest Shackleton (1874–1922), Antarctic explorer during the Heroic Age of Antarctic Exploration.
• Robert E. Horton (1875–1945), founder of modern hydrology and concepts such as infiltration capacity and overland flow.
• J Harlen Bretz (1882–1981), pioneer of research into the shaping of landscapes by catastrophic floods, most notably the Bretz (Missoula) floods.
• Willi Dansgaard (born 1922), palaeoclimatologist and quaternary scientist, instrumental in the use of oxygen-isotope dating and co-identifier of Dansgaard-Oeschger events.
• Hans Oeschger (1927–1998), palaeoclimatologist and pioneer in ice core research, co-identifier of Dansgaard-Orschger events.
• Richard Chorley (1927–2002), a key contributor to the quantitative revolution and the use of systems theory in geography.
• Sir Nicholas Shackleton (1937–2006), who demonstrated that oscillations in climate over the past few million years could be correlated with variations in the orbital and positional relationship between the Earth and the Sun.
• Stefan Rahmstorf (born 1960), professor of abrupt climate changes and author on theories of thermohaline dynamics.

See also

• Ecology
• Environmental science
• Environmental studies
• Geostatistics
• Weathering
• Physiographic regions of the world

References

Further reading

• Smithson, Peter; et al. (2002). Fundamentals of the Physical Environment. Routledge, London. 
• Holden, Joseph (2004). Introduction to Physical Geography and the Environment. Prentice-Hall, London. 
• Summerfield, Mike (1991). Global Geomorphology. Longman, London. 
• Wainwright, John; Mulligan, M. (2003). Environmental Modelling: Finding Simplicity in Complexity. John Wiley and Sons Ltd, London. 
• Strahler, Alan; Strahler Arthur (2006). Introducing Physical Geography. Wiley,New York. 
• Yang, Xin-She (2009). Introductory Mathematics for Earth Scientists. Dunedin Academic, Edinburgh. 
• Inkpen, Robert (2004). Science, Philosophy and Physical Geography. Routledge, London. 

External links

• Physiography by T.X. Huxley, 1878, full text, physical geography of the Thames River Basin
• Fundamentals of Physical Geography, 2nd Edition, by M. Pidwirny, 2006, full text
• Physical Geography for Students and Teachers, UK National Grid For Learning

Subfields of physical geography Biogeography · Climatology / Paleoclimatology · Coastal geography · Geomorphology · Glaciology · Hydrology / Hydrography · Landscape ecology · Limnology · Oceanography · Palaeogeography · Pedology · Quaternary science