Revision Lecture Flashcards
who said ‘geography is primarily concerned to describe … the variable character of areas as formed by existing features in interrelationships’ ?
Hartshorne, 1939
who said ‘Geography has to be conceived as the science concerned with the formulation of the laws governing the spatial distribution of certain features on the surface of the earth’
Schaefer, 1953
What is Physical Geography?
Sub-discipline of Geography concerned with the study of processes and spatial patterns in the natural environment like the atmosphere, hydrosphere, cryosphere, biosphere, and geosphere, as opposed to the cultural or built environment, the domain of human geography.
when was catastrophism?
until 1830s
when was uniformitarianism?
1830-1930
when was Davies’ Cycle of erosion
1890-1950
what is ‘catastrophism’?
Ascribes the origin of Earth’s landforms to one or more “catastrophic” themes:
George Cuvier (1769-1832) Robert Jameson (1774-1854) Archbishop Ussher, 1650
what is ‘uniformitarianism’?
Also termed Gradualism
“The present is the key to the past”
(coined by Whewell, 1832):
Natural processes shape landforms through
gradual changes over long periods of time.
what is Davisian cycle of Erosion?
(a) young uplifted stage with very limited incision
(b) mature stage with deep valley incision and complex topography
(c) old eroded landscape with few topographic features
what is ‘glacial theory’?
1846 - louis agassiz
- multiple glaciations
- most of northern europe in N America, N Asia, had been covered by ice sheets during a period later termed the pleistocene
Dynamic equilibrium in stream flow (Gilbert 1877)
Quantitative revolution (1950s): move to quantitative and statistical approaches (e.g. Arthur Strahler)
Rejuvenation of equilibrium concept (Hack 1960)
The Equilibrium Concept
Equilibrium over three timescales:
(a) dynamic equilibrium; b) steady-state equilibrium; (c) static equilibrium
Climatic geomorphology (Julius Büdel, 1960s)
1950s Advance in quantitative geography
Empiricism
Cause – effect relationships (1970s)
The Scientific Method
Magnitude – Frequency concept
fieldwork strengths
- Measurements in ‘real world conditions’
- Gives better understanding of the system
- Observation together with measurements
- Changeable conditions
- No major limitations with scale of experiment
fieldwork weaknesses
- Environmental conditions difficult to control
- Even for long-term experiments conditions may be non-representative (odd year)
- Equipment sometimes vandalised
- Challenging conditions: cold, hot, wet, insects..
Lab work strengths
- Measurements in ‘controlled conditions’
- Very precise measurements of properties
- Not so restricted by logistics and time
lab work weaknesses
- Difficulties in scaling up results from the laboratory to the field
- The simplicity of experiments ignore complex feedbacks and inter-linkages in the real world (similar to models)
- Difficult to judge how representative it is in real conditions
remote sensing advantages
-Spatial coverage - Global
& Increasingly high resolution
- Regular repeat observations - Frequency depends on instrument and orbit
- Easy access to data - Most data is available over the internet
- Huge archive of data - Multi-decadal for some missions
- Variety of derived products
remote sensing limitations
- Trade off between spatial and temporal resolution Polar orbiting v geostationary Swath width v resolution - Large amount of data to handle Can take time to download and process - Length of time series May not be as long as in-situ observations - Continuity of observations Instrument failure or mission lifetime
