heat island effect Flashcards
what is the heat island effect?
term to describe the higher air and structure temperatures in an urban setting as opposed to the lower temperatures found in more rural areas. With fewer trees in cities and large communities, solar energy is more readily absorbed into manmade structures
why is the heat island effect an issue?
urbanization is increasing, and there are more people in urban areas than rural, this is gradually on the rise.this will increase the heat.
why does land use matter?
if you distribute all the houses and green areas evenly throughout the whole of the UK, the heat will decrease overall.
what are land sharing and land sparing?
all in one place and a massive green bit or dispersed all over the place
case study: Southampton. how many parks and people and km squared does SU have?
50 parks, 245,000 people and 50 km squared.
how do you get the information on the temperature in a city?
use of thermal land of Landsat 7 ETM+. temperature monitors. can also use satellites to see different energy rays and thermal bands.
what are the issues with the processes of getting information about temperatures?
the clouds can cause problems for satellite remoting, SLC off effects corrected. imagery processed at 30 m resolution is corrected from emissivity using land classes.
how do you calculate the deriving land surface temperature?
big equation. has Boltzmann constant in. dont need to know, but it is:
LST= BT/ [1+ λ*BT/α * ln(ε)].
where LST= land surface temperature. BT= brightness temperature in K, λ = wavelength of emitted radiance in m (11.45µm), α = constant derived as h * c / σ where h = Planck’s constant 6.26 x 10-34, c = the speed of light 2.998 x 108 and σ = the Boltzmanconstant 1.38 x 10-23, ε = emissivity of the surface in the range 0 to 1
what are the limitations of land surface temperature from the imagery of maps?
it varies a lot, the roofs of buildings and metal containers can cause inaccurate results due to radiation and expansion of materials.
what is anthropogenic heat?
buildings get hotter due to heating and cooking.
what is a hot island in short?
an area in which the observed temperature exceeds the mean plus one standard deviation.
what is modelling land surface temperature?
try to uncover the drivers of and surface temperature if we model it.
what happens when you increase the amount of green in LST predictors and why?
the percentage of heat goes down. natural surfaces have a high percentage of relative importance,
what is a neutral landscape?
one that hasn’t been developed with natural resources. one that we have created.
what happens when you mix up the pixels?
the same proportion of hot and cold, but they have been rearranged the land use to random areas. changed temperature overall.
