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Figure 5.12: Diurnal cycle of the wind speed (ms -1 ) (the upper panel) and wind direction (the lower panel) at the LHR station from August 6 th to August 7 th 1998 according to LHR measurements (blue), the traditional METRAS simulation (pink) and the simulation with BEP (yellow). ...................................................................................................................155 Figure 5.13: Diurnal cycle of the wind speed (ms -1 ) at the LHR station from 30 th -31 st July 1999 according to LHR measurements (blue), the traditional METRAS simulation (pink) and the simulation with BEP (yellow)..................................................................................156 Figure 6.1: Potential temperature difference (K) between the base case of current urbanised land use (URB_BASE) and a rural case (NOURB) at z = 10 m at 04:00 (left) and 12:00 (right) of the second day of simulation. ...............................................................................170 Figure 6.2: Diurnal cycle of the maximum UHI intensity (K) for the second day of simulation for the URB_BASE case. The UHI intensity is calculated for the current urban land cover case with respect to the rural domain (NOURB). ..................................................176 Figure 6.3: Diurnal variation of the London UHI with respect to Bracknell for six days in July and August 1999/2000. Taken from Wilby (2003)............................................................178 Figure 6.4: Horizontal wind speed difference (ms -1 ) between the base case of current urbanised land cover (URB_BASE) and rural domain (NOURB) at z = 10 m at 04:00 (left) and 12:00 noon (right) of the second day of simulation...........................................................180 Figure 6.5: Horizontal wind speed and direction (ms -1 ) for the base case of current urbanised land cover (URB_BASE) (left) and rural domain (NOURB) (right) at z = 10 m at 04:00 of the second day of simulation..................................................................................181 Figure 6.6: Mean potential temperature (K) as a function of the mean urban land cover fraction for the COMBINED, RADIUS and DENSITY series, at 04:00 of the second day of simulation. .....................................................................................................................188 Figure 6.7: Mean potential temperature (K) as a function of the mean urban land cover fraction for the COMBINED, RADIUS and DENSITY series, at 12:00 of the second day of simulation. .....................................................................................................................189 Figure 6.8: Mean DTR (K) as a function of the mean urban land cover fraction for the COMBINED, RADIUS and DENSITY series, for the second day of simulation. ...194 Figure 6.9: Spatially averaged maximum diurnal temperature (K) as a function of the mean urban land cover fraction for the COMBINED, RADIUS and DENSITY series, for the second day of simulation..................................................................................................195 Figure 6.10: Spatially averaged minimum diurnal temperature (K) as a function of the mean urban land cover fraction for the COMBINED, RADIUS and DENSITY series, for the second day of simulation..................................................................................................196 Figure 6.11: Diurnal cycle of the maximum UHI intensity (K) for the second day of simulation for the RADIUS series............................................................................................................197 Figure 6.12: Diurnal cycle of the maximum UHI intensity (K) for the second day of simulation for the DENSITY series.........................................................................................................198 Figure 6.13: Diurnal cycle of the maximum UHI intensity (K) for the second day of simulation for the COMBINED series....................................................................................................198 Figure 6.14: Maximum UHI intensity (K) as a function of mean urban land cover fraction for the RADIUS, DENSITY and COMBINED series of model runs, at 02:00 of the second day of simulation. .......................................................................................................199 Figure 6.15: Mean horizontal wind speed at z = 10 m as a function of the mean urban land cover fraction for the RADIUS, DENSITY and COMBINED series of model runs, at 12:00 of the second day of simulation..................................................................................201 x
Figure 6.16: Mean horizontal wind speed at z = 10 m as a function of the mean urban land cover fraction for the RADIUS, DENSITY and COMBINED series of model runs, at 04:00 of the second day of simulation..................................................................................202 Figure 7.1: Mean potential temperature (K) as a function of the mean urban land cover fraction as computed by the simulations of the EXPANSION series at 04:00 of the second day of simulation ........................................................................................................216 Figure 7.2: Mean potential temperature (K) as a function of the mean urban land cover fraction as computed by the simulations of the EXPANSION series at 12:00 of the second day of simulation ........................................................................................................217 Figure 7.3: Diurnal cycle of the maximum UHI intensity (K) as computed by the simulations of the EXPANSION series for the second day of simulation........................................219 Figure 7.4: Maximum UHI intensity (K) as a function of mean urban land cover fraction as computed by the simulations in the EXPANSION series at 02:00 of the second day of simulation...................................................................................................................................220 Figure 7.5: Mean DTR (K) as a function of the mean urban land cover fraction as computed by the simulations in the EXPANSION series for the second day of simulation.......222 Figure 7.6: Mean horizontal wind speed (ms -1 ) at z = 10 m as a function of the mean urban land cover fraction as computed by the simulations in the EXPANSION series at 04:00 (blue) and 12:00 (pink) for the second day of simulation......................................223 Figure 7.7: Change in urban land cover for the model simulation ‘30F’ expressed as a percentage change ....................................................................................................................226 Figure 7.8: Change in the near surface potential temperature [K] at 12:00 noon for the ‘30F’ simulation compared to the base case of current urban land use for London.............228 xi
Page 1 and 2: MODELLING THE IMPACT OF URBANISATIO
Page 3 and 4: Abstract Urban areas have well docu
Page 5 and 6: Abbreviations aLMo Meteo Swiss oper
Page 7 and 8: 4.2.2 Impact of the urban area on t
Page 9 and 10: List of figures Figure 2.1: Scales
Page 11: Figure 4.21: Diurnal variation of t
Page 15 and 16: Chapter 1: Introduction Urban areas
Page 17 and 18: with trends derived from a statisti
Page 19 and 20: scheme, and therefore it was necess
Page 21 and 22: The effects of future urban expansi
Page 23 and 24: 2.1 Urban climate modification Urba
Page 25 and 26: latitudes (Taha 1997), and this is
Page 27 and 28: 100 - 200 m 1 - 2 km 10 - 20 km 100
Page 29 and 30: epresentatively sample the underlyi
Page 31 and 32: over the city centre, convergent fl
Page 33 and 34: Cold islands can also occur in urba
Page 35 and 36: of the atmosphere. For example, it
Page 37 and 38: amount of solar radiation absorbed
Page 39 and 40: (Peterson 1969; Changnon 1992; Coll
Page 41 and 42: 2.3 Justification of modelling appr
Page 43 and 44: Trusilova (2006) carried out a stud
Page 45 and 46: constant flux surface layer in the
Page 47 and 48: the vertical distribution of vegeta
Page 49 and 50: using different building parameters
Page 51 and 52: Table 2.2: SWOT analysis for the ME
Page 53 and 54: Fraction of urban land cover [%] Fi
Page 55 and 56: The built up area of London can cur
Page 57 and 58: Figure 2.5(a-f): Builtup area of Lo
Page 59 and 60: • Mainly high density development
Page 61 and 62: climate of London, and currently on
Page 63 and 64:
For mid-latitude cities, of which L
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warming of 0.04 °C per decade, in
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out differences in the urban heat i
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adopted in previous studies ranges
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y the implementation of a specific
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A prognostic equation is used to re
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At the surface the temperature is c
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The boundary conditions used for th
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are defined in the file m1tini_TAPE
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The terms representing the impact o
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3.2.1 Calculation of dynamical effe
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θ k ∆z / 2 H Siu (Equation 3.12)
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3.3 Implementation of BEP in METRAS
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difficulties in the linking of the
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Table 3.3: Description of how the 2
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3.5.2 Orography data Orography data
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epresenting suburban development a
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Table 3.7 shows a summary of the MI
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3.6 Summary In this PhD study the m
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temperature, air pressure and air d
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Potential temperature [K] Figure 4.
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Wind speed [ms -1 ] Figure 4.2: Ver
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4.2.1 Horizontal cross sections of
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affected, as the flow bends around
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Downwind of the city on the other h
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the city, which is expected since t
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Potential temperature [K] Figure 4.
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simulation this effect is verticall
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differences are expected during day
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tend to cool the surface, but can a
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Figure 4.15 shows the vertical prof
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appropriate value for these paramet
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0.61) and that of conventional grav
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Difference in potential temperature
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educed near surface temperatures of
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fraction was increased in steps of
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works. In the control simulation th
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characterised by the albedo, therma
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is higher by a similar amount. The
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(a) Potential temperature [K] (c) T
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Figure 4.25 shows the vertical sect
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tests also reproduced well document
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Chapter 5: Evaluation of the urbani
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Fraction of urban land cover [%] Fi
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For the summers of 1995-2000 the an
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Table 5.2: Selected periods of simu
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commonly used as a rural reference
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newly urbanised version of the METR
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adiation trapping in the street can
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the second day of simulation (31 st
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Air temperature ( o C) 35 30 25 20
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the model. The smaller percentage o
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Wind speed (ms -1 ) Wind direction
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London Heathrow Airport (LHR) Wind
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A full set of hourly wind speed and
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contain both roofs exposed to direc
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Chapter 6: The effects of urban lan
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simulations with two hypothetical s
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dependent on the r(i,j), the radial
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centre of the domain was more than
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6.2 Effects of the current state of
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During daytime the shape of the are
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The calculation was performed for t
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ecause finding a rural reference po
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development (GLA 2006) and differen
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6.2.4 Wind speed and direction Klai
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Wind speed and direction (ms -1 ) F
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“urban” cells to be affected by
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the urban surface. Many other studi
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eason the near surface potential te
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Mean potential temperature at 12:00
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where A(x) is the area affected by
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Table 6.8: REI for the RADIUS, DENS
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COMBINED series also show a reducti
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for all runs in the series, and cor
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The runs are then combined into one
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to be more linear than the smaller
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The total reduction in mean wind sp
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The REI showed that for all the var
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Higher temperatures in the urban ar
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Over the next ten years the populat
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7.1.1 EXPANSION series The first sc
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Another cause of this form of expan
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7.2 Effects of urbanisation for the
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Mean near surface potential tempera
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UHI intensity (K) 4 3.5 3 2.5 2 1.5
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temperature, an increase in the mea
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7.2.3 Wind speed The effect of the
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7.3 Effects of urbanisation for the
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mean near surface potential tempera
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7.3.2 Wind speed Changes in the mea
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expansion strategies such as the re
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should also be considered to avoid
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models, for example Martilli et al.
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cities (Baker et al. 2002). Already
Page 253 and 254:
uses, painting the roofs white to r
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The full influence of different met
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References Abercrombie, P. (1945).
Page 259 and 260:
Bottema, M. (1997). "Urban Roughnes
Page 261 and 262:
Craig, K. J. and R. D. Bornstein (2
Page 263 and 264:
Grimmond, C. S. B. and T. R. Oke (2
Page 265 and 266:
Jin, M. and J. M. Shepherd (2005).
Page 267 and 268:
Lemonsu, A. and V. Masson (2002). "
Page 269 and 270:
Nitis, T., Z. B. Klaic and N. Mouss
Page 271 and 272:
alance in urban areas - Recent adva
Page 273 and 274:
Seaman, N. L. (2000). "Meteorologic
Page 275 and 276:
Therry, G. and P. Lacarrere (1983).
Page 277:
Yague, C., E. Zurita and A. Martine
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