Energy Balance at Earth’s Surface Flashcards
What is the daily pattern of incoming shortwave radiation?
Incoming energy arrives during daylight, beginning at sunrise, peaking at noon, and ending at sunset
What is the lag between the insolation curve and the air temperature curve?
Note that the insolation curve and the air temperature curve on the graph do not align; there is a lag between them. The warmest time of day occurs not at the moment of maximum insolation but at the moment when a maximum of insolation has been absorbed and emitted to the atmosphere from the ground. As long as the incoming energy exceeds the outgoing energy, air temperature continues to increase, not peaking until the incoming energy begins to diminish as the afternoon Sun’s altitude decreases.
What is the boundary layer?
Energy and moisture are continually exchanged with the lower atmosphere at Earth’s surface—this is the boundary layer
What is the energy balance in the boundary layer affected by?
The energy balance in the boundary layer is affected by the specific characteristics of Earth’s surface, such as the presence or absence of vegetation and local topography. The height of the boundary layer is not constant over time or space.
What is microclimatology?
Microclimatology is the science of physical conditions, including radiation, heat, and moisture, in the boundary layer at or near Earth’s surface.
“The study of local climates at or near Earth’s surface or up to that height above the Earth’s surface where the effects of the surface are no longer determinative.”
What is a microclimate?
Microclimates are local climate conditions over a relatively small area, such as in a park, on a particular slope, or in your backyard
What is Net radiation?
Net radiation (NET R) is the sum of all radiation gains and losses at any defined location on Earth’s surface. NET R varies as the components of this simple equation vary with day length through the seasons, cloudiness, and latitude.
Energy gains include shortwave from the Sun (both diffuse and direct) and longwave that is reradiated from the atmosphere after leaving Earth. Energy losses include reflected shortwave and Earth’s longwave emissions that pass through to the atmosphere and space.
What is the latent head of evaporation and what dose it to to Net R
The latent heat of evaporation (LE) is the energy that is stored in water vapour as water evaporates. Water absorbs large quantities of this latent heat as it changes state to water vapour, thereby removing this heat energy from the surface. Conversely, this heat energy releases to the environment when water vapour changes state back to a liquid (discussed in Chapter 7). Latent heat is the dominant expenditure of Earth’s entire NET R, especially over water surfaces.
How dose Sensible heat effects Net R
Sensible heat (H) is the heat transferred back and forth between air and surface in turbulent eddies through convection and conduction within materials. This activity depends on surface and boundary-layer temperature differences and on the intensity of convective motion in the atmosphere. About one-fifth of Earth’s entire NET R is mechanically radiated as sensible heat from the surface, especially over land. The bulk of NET R is expended as sensible heat in these dry regions.
How dose ground heating effect Net R
Ground heating and cooling (G) is the flow of energy into and out of the ground surface (land or water) by conduction. During a year, the overall G value is zero because the stored energy from spring and summer is equalled by losses in fall and winter. Another factor in ground heating is energy absorbed at the surface to melt snow or ice. In snow- or ice-covered landscapes, most available energy is in sensible and latent heat used in the melting and warming process.
Where are LE and H values the highest
On land, the highest annual values for LE occur in the tropics and decrease toward the poles. Over the oceans, the highest LE values are over subtropical latitudes, where hot, dry air comes into contact with warm ocean water. The values for H are highest in the subtropics. Here vast regions of subtropical deserts feature nearly waterless surfaces, cloudless skies, and almost vegetation-free landscapes.
What produces the global climate system?
Through the processes of latent, sensible, and ground heat transfer, the energy from net radiation is able to do the “work” that ultimately produces the global climate system—work such as raising temperatures in the boundary layer, melting ice, or evaporating water from the oceans.
How much hotter can urban areas be then surrounding suburban and rural areas?
Urban microclimates generally differ from those of nearby nonurban areas, with urban areas regularly reaching temperatures as much as 6 C° hotter than surrounding suburban and rural areas. In fact, the surface energy characteristics of urban areas are similar to those of desert locations, mainly because vegetation is lacking in both environments.
What is an Urban heat island
An urban microclimate that is warmer on average than areas in the surrounding countryside because of the interaction of solar radiation and various surface characteristics.
