Abstract:

Taking into account different anthropogenic heat (AH) sources from manufactories，vehicles and residents, we estimated the anthropogenic heat flux (AHF) in Xi’an, firstly, including energy consumptions by industry and residents, amounts of vehicles, traffic volumes of the main roads, etc. The estimated AHF was consistent with the urban development. Then we carried out a sensitivity test about AHF using WRF/UCM model, including anthropogenic heat (AH) with diurnal variation. The results are as follows: (1) The WRF/UCM model could better characterize precipitation distribution in detail. AH effect could improve the simulation of temperature distribution and intensity, which could also make the urban ground flow field and precipitation distribution and intensity more close to the reality.（2）Urban buildings could intercept long-wave radiation energy, AH also enhanced the strength of long-wave radiation energy and enlarged surface upward sensible heat flux. (3) AH effect on the increase the boundary layer height was more obvious, with an average value of 50 to 100 meters. It was concluded that the sensitivity test about AH flux by using WRF/UCM model could increase the downstream vertical velocity, strengthen the local vertical circulation and decrease convective horizontal scale. With the fine land-use data and AHF, the vertical structure of atmosphere had changed, which resulted in rainfall intensity in different parts of the city.

Key words: anthropogenic heat, WRF/UCM model, meteorological elements, sensitivity test

摘要：

利用西安市工业和生活能源消耗量、汽车保有量、主干道车流量等数据，对工业、交通和生活3种人为热排放量进行综合估算，利用耦合到WRF模式中的单层城市冠层模式(WRF/UCM)，采用修订的西安人为热日逐时变化参数，对城市化及人为热的影响进行敏感性分析。结果表明：（1）采取修订后的人为热源参数，耦合城市冠层的模式系统更能详细刻画出降水分布的局地性差异，人为热源对城市温度分布及强度的模拟效果有一定的改进作用，对城市地面流场、降水分布及强度有一定的影响，模拟结果更接近实况；（2）城市冠层对长波辐射有一定的截获作用，在增加人为热源的影响下，城市地表吸收的长波辐射增多更为明显，加强了地表对边界层大气向上的感热输送；（3）人为热源对增加边界层高度的作用较为明显，平均在50～100 m；耦合城市冠层和人为热源后，在城市下风方向，垂直速度增大，局地垂直环流逐渐加强，对流系统水平尺度更小；在城市下垫面和人为热源共同影响下，大气的垂直结构发生了变化，从而造成城区不同部位降水强度的差异。

关键词: 人为热, 城市冠层模式（UCM）, 气象要素, 敏感性分析