24 Impact of Urban Land Use and Anthropogenic Heat on Air …
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occurs at around 8 pm in New York. The reduction of AQHI in New York is much
larger than the reduction in Toronto and Detroit. In July however, the reductions of
AQHI occur in the early morning in the three big cities and large reductions occur
not only in New York, but also in Detroit. Contrary to the big reduction at noon in
January, AQHI has virtually no change at noon in New York and Detroit.
Figure 24.3 also shows that TEB has very different impact on AQHI during weekday and weekend. In January, the reduction of AQHI in early morning in weekday is
much larger than the reduction in weekend in the three big cities. However, in July
the reduction in early morning in weekend is much larger than the reduction in early
morning in weekday in New York and Detroit.
24.4 Conclusions and Future Plans
Our simulations show that the inclusion of TEB in the GEM-MACH simulations can
significantly reduce the cold temperature bias in the urban areas, and has big impacts
on turbulent mixing coefficient and the ABL height (not shown). The simulation
results also show that the change of meteorological condition leads the reduction of
the AQHI in urban centers in both winter and summer.
In the current simulations, the climatologic traffic heat flux is used. In the future
work, the diurnal variation of the traffic heat flux will be used to better describe the
impact of the traffic patterns in urban areas on the UHI effect. In addition, the surface
meteorological analysis data will also be used in future simulations to provide more
accurate information of surface energy balance.
Question and Answer
Questioner: Alexander Baklanov
Questions:
1. Did you consider urban soil moisture processes and their effects?
2. In polluted cities, effects of urban aerosols on UBL and in particular UBL height
can be comparable with UHI effects. Did you consider aerosol feedbacks in your
studies?
3. You use the TEB model in the simulations of Masson [2], which was done for
NWP and meteorological applications. For NWP applications, building effects
on mechanical turbulence and on wind velocity structure in urban canopy is also
important. In NEM/BEP parameterizations by Martilli et al. (2002) and latest version of TEB such effects are included more accurately. Did you analyzed/included
these effects and other parameterizations?
Answer to (1): The air quality model (GEM-MACH) includes the land surface
scheme which takes into account of urban soil moisture processes and their effects.
Answer to (2): The feedback of urban aerosols on simulations is not considered in
this study. However, Wanmin Gong is going to discuss this effect in her talk. The
same model is employed in her work.
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occurs at around 8 pm in New York. The reduction of AQHI in New York is much
larger than the reduction in Toronto and Detroit. In July however, the reductions of
AQHI occur in the early morning in the three big cities and large reductions occur
not only in New York, but also in Detroit. Contrary to the big reduction at noon in
January, AQHI has virtually no change at noon in New York and Detroit.
Figure 24.3 also shows that TEB has very different impact on AQHI during weekday and weekend. In January, the reduction of AQHI in early morning in weekday is
much larger than the reduction in weekend in the three big cities. However, in July
the reduction in early morning in weekend is much larger than the reduction in early
morning in weekday in New York and Detroit.
24.4 Conclusions and Future Plans
Our simulations show that the inclusion of TEB in the GEM-MACH simulations can
significantly reduce the cold temperature bias in the urban areas, and has big impacts
on turbulent mixing coefficient and the ABL height (not shown). The simulation
results also show that the change of meteorological condition leads the reduction of
the AQHI in urban centers in both winter and summer.
In the current simulations, the climatologic traffic heat flux is used. In the future
work, the diurnal variation of the traffic heat flux will be used to better describe the
impact of the traffic patterns in urban areas on the UHI effect. In addition, the surface
meteorological analysis data will also be used in future simulations to provide more
accurate information of surface energy balance.
Question and Answer
Questioner: Alexander Baklanov
Questions:
1. Did you consider urban soil moisture processes and their effects?
2. In polluted cities, effects of urban aerosols on UBL and in particular UBL height
can be comparable with UHI effects. Did you consider aerosol feedbacks in your
studies?
3. You use the TEB model in the simulations of Masson [2], which was done for
NWP and meteorological applications. For NWP applications, building effects
on mechanical turbulence and on wind velocity structure in urban canopy is also
important. In NEM/BEP parameterizations by Martilli et al. (2002) and latest version of TEB such effects are included more accurately. Did you analyzed/included
these effects and other parameterizations?
Answer to (1): The air quality model (GEM-MACH) includes the land surface
scheme which takes into account of urban soil moisture processes and their effects.
Answer to (2): The feedback of urban aerosols on simulations is not considered in
this study. However, Wanmin Gong is going to discuss this effect in her talk. The
same model is employed in her work.