Catchment Hydrology + The Processes of the Carbon Cycle Flashcards
What is evaporation and how does it transfer heat around the planet?
Evaporation is the process by which liquid water changes to vapour and is the main pathway by which water enters the atmosphere. It requires heat, which does not produce a rise in temperature in the water, but rather is absorbed as latent heat and released later in condensation. This process allows for huge quantities of heat to be transferred around the planet, from the oceans to the continents and from the tropics to the poles.
How does vegetation intercept precipitation?
Vegetation intercepts a proportion of precipitation, storing it temporarily on branches, leaves, and stems.
What are the two flowpaths of rainwater that does not enter storage?
Rainwater that does not enter storage follows one of two flowpaths to streams and rivers: infiltration by gravity into the soil and lateral movement or throughflow to stream and river channels, or overland flow across the ground surface either as a sheet or as trickles and rivulets to stream and river channels.
What are the two conflicting ideas regarding the flowpaths of rainwater?
Two conflicting ideas explain the flowpaths followed by rainwater. One relates overland flow to the soil’s infiltration capacity or the maximum rate it can absorb rain. Thus, it is argued that when rainfall intensity exceeds infiltration capacity, overland flow occurs. The second idea states that rainfall, regardless of its intensity, always infiltrates the soil.
What are the factors affecting interception loss according to Table 4.5?
According to Table 4.5, the factors affecting interception loss are the interception storage capacity, rates of evaporation increase with wind speed, turbulence also increases with wind speed causing additional throughfall, vegetation type, and tree species.
How does interception depend on the duration and intensity of a rainfall event?
Interception depends on the duration and intensity of a rainfall event. Before the onset of rainfall, vegetation surfaces are dry and their ability to retain water is at a maximum. Initially, most rainfall is intercepted. However, as vegetation becomes saturated, output of water through stemflow and throughfall increases.
How do wind speed and turbulence affect interception loss?
Rates of evaporation increase with wind speed, and turbulence also increases with wind speed causing additional throughfall.
What vegetation types have higher interception losses than others?
Interception losses are greater from grasses than from agricultural crops. Trees, which have a large surface area and aerodynamic roughness, have higher interception losses than grasses.
Why do evergreen conifers have far greater interception losses than broad-leaved, deciduous trees?
Interception losses are far greater from evergreen conifers (e.g. spruce, pine) than from broad-leaved, deciduous trees (e.g. oak, ash). This is because most conifers have leaves all year round and water adheres to the spaces between conifer needles (like water on a comb), which increases evaporation.
What is ablation?
Ablation is the loss of ice from snow, ice sheets, and glaciers due to a combination of melting, evaporation, and sublimation.
What is the main cause of flooding in adjacent lowlands in Britain during winter?
Rapid thawing of snow in upland Britain in winter is a common cause of flooding in adjacent lowlands.
What is photosynthesis?
Photosynthesis is the process by which green plants and marine phytoplankton convert light energy to chemical energy (glucose) using the Sun’s energy, CO2 from the atmosphere, and water.
What is respiration?
Respiration is the process in which plants release CO2 to the atmosphere while using energy in the form of glucose to maintain growth, reproduction, and other life processes.
What are the main processes involved in carbon exchanges?
The main processes involved in carbon exchanges (or fluxes) are precipitation, photosynthesis, weathering, respiration, decomposition, and combustion.
What is weathering?
Weathering is the in situ breakdown of rocks at or near the Earth’s surface by chemical, physical, and biological processes, and it involves rainwater which contains dissolved CO2 from the soil as well as the atmosphere.
What is interception?
Interception is the process by which vegetation intercepts a proportion of precipitation, storing it temporarily on branches, leaves, and stems.
What is groundwater flow?
Groundwater flow is the slow migration of water through rock pores and joints as groundwater, eventually emerging at the surface as springs or seepages.
What is the process by which atmospheric CO2 dissolves in rainwater?
The process by which atmospheric CO2 dissolves in rainwater to form weak carbonic acid is a natural process.
What is abiotic storage?
Abiotic storage is the storage of water in soil, snow, and ice.
What is infiltration capacity?
Infiltration capacity is the maximum rate at which soil can absorb rainwater. When rainfall intensity exceeds infiltration capacity, overland flow occurs.
What is cryospheric processes?
Cryospheric processes are processes involving snow, ice, and permafrost.
What is the carbon flux from the atmosphere to land plants and phytoplankton via photosynthesis?
The flux of carbon from the atmosphere to land plants and phytoplankton via photosynthesis averages around 120 gigatonnes (GT) a year.
