Water Cycle Flashcards
What is El Nino?
El Nino is an example of equilibrium being broadly maintained over time. It is the reversal of normal air and ocean circulation from South America to Australia.
What is La Nina?
La Nina is the opposite of El Nino, causing an intensification of the Walker Loop.
What is the distribution of ice caps?
- There is very little ice in North America
- Ice caps found in Japan and East Asia, influenced by precipitation, rock type, and weather.
Where are major aquifer systems located globally?
Major aquifer systems are found in Europe, East Russia, Africa, Southeast Asia, and South America.
Where are glaciers predominantly distributed?
Glaciers are largely found in the Himalayas, a belt down the west of South America and North America, East Canada, and Greenland. This distribution is likely due to topography.
What influence does global topography have on aquifers and ice caps?
Lower relief areas typically have more aquifer systems, while higher relief areas often have more ice caps, influenced by tectonic activity or lower temperatures.
What are the challenges related to water sources?
Water sources may be difficult to exploit due to their distribution and the challenges posed by topography.
What is the distribution of potential evaporation?
The northern hemisphere has much lower rates of potential evaporation, with most occurring in Central Africa, likely due to high temperatures near the equator.
What are the challenges of evapotranspiration rates in Africa?
Higher evapotranspiration rates in Africa might require more water imports.
What is the distribution of water stress?
Most water stores are overexploited near the equator and the west coast of South America. In Africa, this is likely due to high evapotranspiration and low precipitation rates.
What are the consequences of water deficit?
Water deficit may cause countries to become reliant on imported water, leading to instability.
What are the short-term changes for atmospheric water?
Storm, causes higher temps, causing more evaporation, causing more water vapour
What are the long-term changes for atmospheric water?
Long-term changes could increase global water vapor levels due to climate change.
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 - Thawing of permafrost leading to GHG emission = +ve feedback loop.
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 deg C warmer.
LT - Climate change increases sea levels and glacier melt.
How do glaciers form and move?
Glaciers form in the ‘Zone of Accumulation’. Corries fill with snow which compacts into firn ice and then into glacial ice. They move as the top layer melts and water runs into cracks providing lubrication.
How much water is undrinkable and why?
97% of water is undrinkable as it is saltwater. A further 70% of freshwater left is locked away as ice or permafrost.
Over the last 100 years, how much have sea levels risen?
Sea levels have risen by 17cm.
What are the short-term (ST) and long-term (LT) factors changing the size of water stores?
Evaporation rates depend on solar energy, water availability, humidity, and air temperature.
Condensation rates depend on air temperature and volume.
Cryospheric processes depend on glacial and interglacial periods and the amount of permafrost.
What are the positive and negative feedback loops for oceanic water?
Positive feedback - Ocean acidification: Oceans absorb CO2, becoming more acidic, leading to less marine life and fewer plants to take CO2 out.
Negative feedback - Ocean warming: As the atmosphere warms, oceans warm, allowing for more carbon storage.
What are the positive and negative feedback loops for atmospheric water?
Positive feedback - Heating: CO2 levels rise causing heating, increasing water temperature, leading to more evaporation and increased water vapor, resulting in more heating (GHG).
Negative feedback - Blocking: Water vapor increases, decreasing the temperature difference between surface and upper troposphere, making GHG less efficient.
What is the positive feedback loop for cryospheric water?
Albedo feedback: ice is reflective; as it melts, dark rock is exposed, absorbing more sunlight and warming up, leading to more melting.
What is the negative feedback loop for cryospheric water?
Cloud formation: increased moisture in the air from melting leads to more clouds formed, which reflect sunlight.
What are the types of rainfall?
Frontal: warm air mixes with cool air, causing lower dew point.
Relief: warm air cools as it’s forced up by mountains, leading to precipitation.
Convectional: sun heats the ground, water vapor rises, cools, condenses, and falls due to gravity.
What conditions are needed for condensation to occur?
Cold temperatures are needed as warm temperatures allow for higher moisture content. Occurs at weather fronts where warm air mixes with cool air, leading to precipitation.
How does condensation work?
Once the dew point is reached, water condenses on surroundings and cools on particles called condensation nuclei, forming clouds.
What are the two types of aquifers?
Unconfined aquifers recharge in days/hours, while confined aquifers take centuries/millennia to recharge.
What challenges exist for aquifer and ice sheet distribution?
Uneven water divide could lead to conflict over water supply.
Which continent has the highest rate of evaporation?
South America experiences rates of over 91mm/month evaporation.
Where else has high evaporation rates?
Western Europe experiences twice as much evaporation as Eastern Europe.
What is a store?
A part of the system where energy/mass is stored or transformed.
What is the dew point?
Point at which an air mass is saturated.
What is the water cycle?
The continuous movement of water on, above, and below the Earth’s surface.
What outputs of glaciers are there?
River - meltwater forms a river.
Calving - snout of glaciers breaks off forming icebergs leading to sea level rise.
Evaporation - water evaporates off.
What proof is there of glacial and interglacial periods?
- Ice cores - show exact CO2 levels at the exact moment.
- Vostok and GISP cores.
Why are glaciated landscapes at risk from climate change?
- Climate change causes a negative mass balance (Input < Output), so glaciers retreat faster than they grow.
Why is there varying evaporation, and where does this occur?
- Solar radiation directed at lower latitudes due to equator positioning.
- Deserts have low rainfall, so lower evaporation rates.
- Antarctica, water freezes before it can evaporate.
- Mountains are higher and therefore colder, so less evaporation.
