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DESERTS Geography concept analys i s. *Agnieszka * Denise * Teshome * Thore *. Ambiguities and Modes of Classification. desert ! = dry land : e.g. volcano deserts d ry / hot deserts ice deserts salt desert. Ambiguities and Modes of Classification.
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DESERTS Geography concept analysis *Agnieszka * Denise * Teshome * Thore*
Ambiguities and Modes of Classification desert != dry land : e.g. volcanodeserts dry/hot deserts icedeserts salt desert Geographic concept analysis - deserts
Ambiguities and Modes of Classification Geographic concept analysis - deserts deserted = uninhabited places; the term does not describe the lack of water (arid place) and deserts may be quite heavily populated in military terminology, desertion is the abandonment of a "duty" or post without permission from one's Government or superior.
RelevantObjectivePrimitives • vegetation • material (rock, sand, ice, salt) • characteristiclandforms (dunes) • humaninhibitions • windspeed • temperature • precipitation • evapotranspiration Geographic concept analysis - deserts
PredicationCriteria Individuation : check the relevant objective primitives ( precipitation, evapotranspiration) Demarcation: sudden change in physical paramters (c) Identity : one connected place of sand, ice … Geographic concept analysis - deserts
PredicationCriteria Example Sahara • typical turning circle desert • cloud free sky • no vegetation • arid • high temperature changes • windy • Ground inversion • animals and plants: Fennec Fox, Rose of Jericho Geographic concept analysis - deserts
PredicationCriteria Example : Antarctica • whole continent desert • borders of the continent (floating ice/underlying rock) • extreme changes over time in the year Geographic concept analysis - deserts
Parameters of variability • temperature is not always high (->ice desert) • the changes of temperature can be huge - daily amplitudes up to 40°C • for many years no drop of water can fall but in the following year a huge amount can fall • different continents have different values of maximum precipitation for land called desert • air in the desert is not always dry - it can have up to 70% humidity Geographic concept analysis - deserts
Parameters of variability • different landforms depending on many factors • in some deserts there are specialized animals • close to sea does not mean humid -> Namib Desert • the cover of the desert can be very different depending on the type of the desert (snow, sand, stones, rocks, etc.) • the origin can vary (natural processes as climate changes after glacial period to anthropological reasons like deforestation) Geographic concept analysis - deserts
Definitions • average annual precipitation of less than 250 millimeters per year • more water is lost by evapotranspiration than falls as precipitation • vegetation cover is sparse to almost nonexistent • sand, rocky, ice Geographic concept analysis - deserts
Definitions/Characteristics Geographic concept analysis - deserts
Axioms Expressing Relations to other Geographic Concepts • region(Sahara). • region(Antarctica). • region(Great Salt Lake Desert). • all x (region(x) & precipitation(x)<250 & precipitation(x)<evapotranspiration(x) -> desert(x)). Geographic concept analysis - deserts
Axioms Expressing Relations to other Geographic Concepts • all x (region(x) & hightempdiffsdaynight(x) -> applicableTemperature(x)). • all x (region(x) & (vegetation(x)=sparse | vegetation(x)=no) -> applicableVegetation(x)). • all x (region(x) & (material(x)=rock | material(x)=sand | material(x)=ice | material(x)=salt) -> applicableMaterial(x)). • all x (applicableTemperature(x) & applicableVegetation(x) & applicableMaterial(x) -> mostlikelyDesert(x)). Geographic concept analysis - deserts
Axioms Expressing Relations to other Geographic Concepts • all x (region(x) & (desert(x) | mostlikelyDesert(x)) & (material(x)=sand | material=rock) & temperature(x)>20 -> hotDesert(x)). • all x (region(x) & (desert(x) | mostlikelyDesert(x)) & material(x)=salt -> saltDesert(x)). • all x (region(x) & (desert(x) | mostlikelyDesert(x)) & temperature(x)<10 -> iceDesert(x)). • all x (iceDesert(x) -> smaller(x, Antarctica)). • all x (hotDesert(x) -> smaller(x, Sahara)). • all x (saltDesert(x) -> smaller(x, Great Salt Lake Desert)). Geographic concept analysis - deserts
Thank youfor your attention! Meerkats inKalahari desert