The Water Cycle Flashcards
What is the Water Cycle?
The continuous movements of water on, above and below the Earth’s surface
What is El Nino?
El Nino is an example of equilibrium being broadly maintained over time. It is the reversal of trade winds and ocean circulation from South America to Australia. It causes waters in Peru to rise 30cm and they are 6-8 degrees warmer
What is La Nina?
La Nina is an exaggerated version of a normal year, with a very strong Walker loop - the opposite of El Nino
What is the distribution of ice caps?
There are very few in the Americas, but some in central Africa, Europe and East Asia
What is the distribution of major aquifer systems?
Most aquifer systems are found in Europe, East Russia, Central Africa, Southeast Asia and South America
What is the distribution of glaciers?
Glaciers are largely found in the Himalayas, Andes - West of South America, Greenland, West of North America
What influence does global topography have on aquifers and ice caps?
Low relief areas tend to have more aquifer systems while higher relief areas often have more ice caps
What are the challenges related to water sources?
Water sources may be difficult to exploit due to their distribution and challenges posed by topography
What is the distribution of water stress?
Most water stores are overexploited along the equator and along the west of both North and South America.
What are the consequences of water deficit?
Water deficit may cause countries to become reliant on imported water, leading to instability
What is the distribution of water?
96.5% of water is stored in the oceans, only 2.5% is freshwater of which 68.7% is locked away in the cryosphere as glaciers and ice caps with another 30.1% stored as groundwater, leaving only 1% easily accessible for human needs
What are the types of rainfall?
Frontal, relief and convectional
What is the dew point?
The point at which an air mass is saturated
What are the two types of aquifer?
Unconfined aquifers recharge in days/hours while confined aquifers take centuries/millennia to recharge
What are the short term (ST) and long term (LT) changes for atmospheric water?
ST - storms cause higher temperatures, causing more evaporation and more water vapour
LT - climate change could increase global water vapour levels
What are the short term (ST) and long term (LT) changes for cryospheric water?
ST - seasonal changes and climate events lead to glacier retreat
LT - interglacials and glacials
What are the short term (ST) and long term (LT) changes for oceanic water?
ST - El Nino causes Peru waters to rise 30cm and are 6-8 degrees warmer
LT - climate change increases sea levels and glacier melt
What are factors affecting evaporation?
Solar energy, water availability, humidity, air temperature
How do glaciers form and move?
Glaciers form when corries fill with snow in the “zone of accumulation” which compacts into firn ice and then into glacial ice. They move as the top layer melts and basal meltwater runs into cracks providing lubrication
Over the last 100 years, how much have sea levels risen?
17cm
What are positive and negative feedback loops for oceanic water?
Positive - ocean acidification: oceans absorb CO2, becoming more acidic, leading to less marine life and fewer plants to absorb CO2
Negative feedback - oceans as carbon sinks: as sea levels rise, the oceans can absorb more CO2
What are the positive and negative feedback loops for atmospheric water?
Positive - heating: CO2 levels rise causing heating, increasing water temperature, leading to more evaporation and increased water vapour, resulting in more heating as it is a greenhouse gas
Negative - cloud formation: increased moisture in the air leads to more clouds forming which reflects sunlight
What are the positive and negative feedback loops for cryospheric water?
Positive - albedo feedback: ice is reflective and as it melts, dark rock is exposed, absorbing more sunlight and heating more, leading to more melting
Positive - permafrost melting: melting permafrost releases methane which is a greenhouse gas and enhances the greenhouse effect
Negative - cloud formation: increased moisture in the air due to melting ice leads to more clouds forming which reflects sunlight
What proof is there of glacial and interglacial periods
Ice cores - show exact CO2 levels at the exact moment (eg. greenland ice sheet project)
