Note:
I've kept the English
spellings because
I was too lazy to change
all of them, and used mainly
direct quotes, rather than
summarizing them in
my own words
direct quotes, rather than
summarizing them in
my own words
T max = maximum temperature of a day
T min = minimum temperature of a day
UHI = Urban Heat Island effect
" How much has
urbanisation affected
United Kingdom
temperatures ? "
by Ian L. M. Goddard
and Simon F. B. Tett
March 28, 2019
Atmospheric Science Letters
published by John Wiley & Sons Ltd
on behalf of the
Royal Meteorological Society.
This study estimated
the affect of urbanisation
on daily maximum
and minimum
temperatures in the
United Kingdom.
" ... This study looked
only at differences
in recorded and reanalysis
temperature data, and
not the rate at which
they are changing
with respect to
one another."
Urban fractions were calculated
for 10 km × 10 km areas surrounding
meteorological weather stations.
"This study finds there is no significant
urban effect on the daily maximum 2‐m
temperature but does find a significant
increase in the daily minimum
2‐m temperature due to urbanisation."
"The relationship found for T min
in this study is in agreement with
the results found by
Trusilova et al. (2008)
and shows a slightly stronger
relationship than that found by
Grawe et al. (2013)."
"The observed
increase in T min
can be attributed
to an increased
intensity of the UHI
( urban heat island )
during the hours
after sunset
and into the night."
"Many studies
have previously shown
that UHII is maximised
during the night."
(Arifwidodo and Tanaka, 2015;
Montávez et al., 2000;
Ripley et al., 1996).
"The intensity is maximised
during these hours,
as heat absorbed by
urban structures will be
re‐radiated back
into the atmosphere ... "
"With minimum temperatures
often occurring at night,
the slowed rate of cooling
in urban areas results in an
increase of the observed
minimum temperature."
"We observe that when considering
an area of 400 km2 over 100 km2
the effect may be increased,
suggesting that a larger area
may influence the UHII more
than originally proposed
in this study."
This paper finds, using a method
of observation minus reanalysis,
that urbanisation significantly
increased the daily MINIMUM
2‐meters off the ground
temperature in the
United Kingdom
by up to +1.70 K.
"For annual average ΔT min,
an urbanisation effect of
1.90 ± 0.88 K is found."
"Stronger relationships are found
for ΔT min in the summer months
where the maximum UHII reaches
2.17 ± 0.78 K in May."
"The urban heat island (UHI)
develops through changes
to the surface energy balance
due to anthropogenic (man made)
modifications to the land surface."
"Previous studies have generally
concluded that urban warming
has had a negligible effect on
global scale temperature series
(Peterson et al., 1999; Parker, 2004)."
"For example, Jones et al. (1990)
showed that the urban warming effect
corresponds to no more than 0.1 K
over the last century. "
"However on regional scales,
the affect of urbanisation
on temperature
may be significant."
"Specifically in China,
where there has been
large expansion of urban areas,
a significant effect
has been estimated."
"Yan et al. (2010) concluded a large impact
of urbanisation up to 0.54 K/decade
on local temperature series in Beijing."
"Whilst Zhou et al. (2004) showed
a smaller urban effect
of about 0.05 K/decade
in south east China."
"Yan et al. (2010) measured
the significance of urbanisation
by comparing temperature time series
for urban and rural weather stations,
observing a greater warming
at urban sites."
"However, it is
difficult to classify
weather stations as
either urban or rural."
"In their study Yan et al. (2010)
used population density as
a marker for urbanisation."
"However, this data is often
out of date and can be hard to obtain
for rural areas
(Wang and Chen, 2016)."
"Satellite data has also been used
to asses the urbanisation of an area."
"Hansen et al. (2001) used
satellite measurements of
night‐time light emissions
to classify weather stations
as either urban, semi-urban or rural;
where a station classed as urban
was located in a bright area,
a semi-urban station was located
in a dimly lit area and a rural station
in an unlit area."
"However ... stations classed as urban
may be located inside well lit city parks,
where the UHII is reduced by the
park cool island (PCI) effect
(Cao et al., 2010)."
"This study aims to deal with the problem
of urban/rural classification by determining
the degree of urbanisation of a given
weather station, rather than having
discrete classes."
"This is done through
the use of a land cover /
land use dataset
derived from satellite images
to asses the fraction
of urban material
around weather stations
(termed urban fraction)."