Modelling the impact of urbanisation on regional climate in the Greater London Area
Modelling the impact of urbanisation on regional climate in the Greater London Area
复制标题
DOI：
10.1002/joc.3589
复制
发表时间：
2013-08-01
期刊：
影响因子：
--
通讯作者：
Schluenzen, K. Heinke
中科院分区：
文献类型：
--
作者：
Grawe, David;Thompson, Heather L.;Schluenzen, K. Heinke
城市地区对气候的影响有充分的文献记载，如城市热岛效应、风速降低、湍流和边界层高度增加以及云量和降水量的变化。本研究的目的是量化伦敦城市地区对当地和区域气候的影响。这是通过非静力学中尺度模式METRAS与复杂的城市冠层方案BEP的耦合来实现的。该模型被配置为案例研究的伦敦地区，典型的城市热岛条件下，和模型的结果进行评估，使用气象监测站点的数据。本研究开发了一种方法，从数值模型的结果来量化城市化的区域影响。城市地区，在其目前的形式，被发现影响近地面温度，昼夜温差，城市热岛，近地面风速和风向。对于选定的情况下，峰值UHI强度高达2.5 K，发现在夜间时间小时，与时间和幅度的峰值显示良好的协议与以前的实验研究伦敦。城市热岛强度峰值的时间为目前的城市土地覆盖伦敦显示出良好的协议与测量结果。由于城市的粗糙度高于农村地区，白天和夜间城市地区的风速也显着降低。结果表明，这种影响具有区域性，城市和周边农村地区都表现出重大影响。因此，城市热岛效应不仅可以被理解时，专注于本地数据，但与周围环境的相互作用需要加以考虑。
Urban areas have well-documented effects on climate, such as the urban heat island (UHI) effect, reduction of wind speeds, enhanced turbulence and boundary layer heights, and changes in cloud cover and precipitation. The aim of this study is to quantify the impact of the urban area of London on local and regional climate. This is achieved through the coupling of the non-hydrostatic mesoscale model METRAS with the sophisticated urban canopy scheme BEP. The model is configured for case studies of the London region, for typical UHI conditions, and the model results are evaluated using data from meteorological monitoring sites. This study develops a methodology to quantify the regional impact of urbanisation from numerical model results. The urban area, in its current form, is found to affect near surface temperature, the diurnal temperature range, the UHI, and the near surface wind speed and direction. For the selected cases, peak UHI intensities of up to 2.5 K are found during night time hours, with the timing and magnitude of the peak showing good agreement with previous experimental studies for London. The timing of the UHI peak intensity for the current urban land cover for London shows a good agreement with the results of measurements. A significant reduction in wind speed over the urban area was also simulated during both daytime and night time, due to the higher roughness of the city compared to the rural domain. The effect is shown to have a regional character, with both urban and surrounding rural areas demonstrating a significant impact. Thus, the UHI can not only be understood when focussing on local data, but the interaction with the surrounding needs to be considered.