Lecture 8: Global Hydrological Cycle Flashcards
What type of system is the global hydrological cycle? (open, closed, isolated…)
Closed system! All water on earth arrived from comets but no water has arrived on earth since then.
What are the major reservoirs in the global hydrological cycle?
- Atmosphere (water vapour)
- Terrestrial water (lakes, rivers, groundwater…)
- Oceans
What are the major linkages in the global hydrological cycle?
- Evaporation
- Transpiration
- Condensation
- Precipitation
- Sublimation
- Movement of runoff
What is the main factor that drives condensation rate?
Vapour pressure: condensation occurs when a vapour water molecule comes in contact with a liquid water molecule. Therefore, with increased vapour pressure, this collision is more likely to occur, thus increasing the condensation rate.
Increased vapour pressure = increased collisions = increased condensation
What is the main factor that drives evaporation rate?
Temperature: evaporation occurs when a liquid water molecule has enough energy to break from the bonds within the liquid.
Increased temperature = more available energy = more evaporation
How does condensation relate to clouds and precipitation
Water vapour uses dust particles or chemicals produced by plants as a basis for condensation. Once this condensation begins at a seeding point, more liquid will condense intothe same droplet, until it is large enough to be acted on by gravity, where it falls to the ground (precipitation).
What is transpiration?
Conversion of liquid water to water vapour by plants.
What is the residence time formula for the hydrological cycle?
residence time = reservoir volume / flow rate
What is sublimation/deposition?
Sublimation: solid to vapour
Deeposition: vapour to solid
What are the main reasons for terrestrial landscapes?
- formation of new rock & recycling of older rock (driven by plate tectonics)
- weather and erosion of existing rock driven by water movement
What is runoff water?
All water that lands on land eventually must drain into the ocean. Some rainfall water spends periods of time in water reservoirs (lakes/groundwater) and some goes directly to oceans in direct runoff or movement through rivers.
What is relative humidity?
The amount of water vapour in the air compared to the total amount of vapour the air can hold. Ex: 100% RH means that condensation and evaporation rate are equal and the air contains the exact amount of water that it can hold.
