W - 1.0 -> 1.4 Flashcards
Systems Approach:
- Storages. - where water is held
- Processes - physical mechanisms that drive
- Fluxes - rate of low
Water budgets:
- Balance of flux vs storage
- Majority of water in salt water storage and inaccessible
- Some sources are replenished, others can’t (e.g. groundwater/ ice sheets)
Types of system:
- Open, e.g. drainage basin
- Closed, e.g. hydrological cycle (solid ice, water vapour, liquid flow)
Water budget change:
- Human activity (extraction/ reservoirs/ drinking)
- Climate change (evaporation, precipitation, melting)
much less freshwater than
saltwater in the world
most of the freshwater stored within
glaciers and ice caps, next largest proportion in permafrost - inaccessible
stores:
- Ocean
- Lakes
- Clouds
- Soil
- Plants and animals
- Ground
fluxes:
Evaporation from ocean, lakes and soil
amazon basin:
- Interception of rainfall and subsequent Evapo-transpiration levels in the Amazon are extremely high owing to dense canopy cover.
- In this way, the Amazon rainforest can be thought of as a self-perpetuating ‘semi-closed’ system.
- As the precipitation levels are so high, there is still a large quantity that reaches the ground – either directly or via Stemflow (water runs down outside of stem).
amazon basin pt 2
- High temperatures and moisture content have meant the shield bedrock has been subject to significant chemical weathering.
- Soil is extremely thin, and overlies thick layers of Kaolinite clay (low permeability)
- High levels of surface run-off / overland flow and nutrient depletion into ‘Whitewater’ Amazon River (limited infiltration)
- Some carbonate rocks near Amazon source have allowed percolation into deep groundwater storage – flows very slowly as Rio Hamza (4km deep).
the amazon:
-Originally flowed westwards from central shield mountains into Pacific (when continents were joined).
- Subsequent tectonic activity separated continents and created Andean mountain range to block westward flow.
- Enormous lakes formed between mountains until point when Andean uplift reversed land dip and direction of flow.
- Now the largest river by discharge volume of water in the world (209,000 cumecs) and largest drainage basin.
- Represents 20% of global riverine (freshwater) discharge to the ocean.
if precipitation increases
- Annual river runoff increases
- Soil moisture increases
- Evaporation increases
- Evapotranspiration increases
- Precipitation further increases
- If precipitation decreases
- Less evapo(transpiration) and further precipitation / runoff
- Less soil moisture
precipitation levels
- Extremely high at the equator (1,500mm +) owing primarily to convectional rainfall at the Inter-tropical convergence zone (ITCZ).
- Green band (below) shows high levels of evaporation and transpiration at ITCZ.
cherrapunji
Wettest place in the world, almost… (record for most in a month/yr)
But: colossal inaccess to water
- Topsoil washed away
- Monsoon climate + orographic rain
- `Winter drought
- 9-26,000 mm/yr
Khasi Hills from Bangladeshi Plain
History:
- Original name Sohra: pronounced ‘Churra’ by British
- Trans: ‘land of the oranges’
a monsoon is
a sea breeze at an immense magnitude, which occurs as a result of the difference in heating between land and sea. Land is more susceptible to Change in temperature compared to sea water, and therefore this causes pressure differences when both are heated, which creates a wind flow
Monsoonal climates are dependent on
changes in the direction of prevailing wind, as this changes where the precipitation occurs, this means monsoonal climates generally consist of predictable wet and dry seasons
60% if the world lives in regions that are
affected by monsoonal climates
The Indian summer monsoon occurs when
the sun climbs higher than the northern hemisphere, heating the continent, and this creates a flow of wind travelling onshore as wind travels from high to low pressure areas
