摘要
利用南京大学城市尺度边界层模式（UBLM），对方圆20km的一个小城镇，以100m水平格距进行了城市气象环境和边界层结构的数值模拟。结果表明，这种规模的小城镇，其边界层气象场分布与大城市最明显的差异就是城乡温差很小，不论白天还是晚上只有0．1～0．2℃的量值，基本不构成城市热岛现象。在日间层结不稳定情况下，主城区、郊区及居民区三类不同下垫面上的湍能廓线、位温廓线存在较大差异；而在夜间稳定情况下，这些要素的廓线分布几乎显现不出下垫面影响的差异。（1）局部下垫面的变化对模拟域内夜间气象环境的影响较小，差异主要显现在日间，且风速分布的变化强于温度变化。（2）当预留地建成稀疏居民区或稠密主城区时，在试验区下风方向的原有城市下垫面上会有气温升高、水平风速减小，垂直速度增大的现象；而当预留地建成平坦机场或水域时，城市下垫面上会有降温、水平风速增大、垂直速度减小的现象。（3）水域对城市气象环境变化的影响最大，它的存在或扩大会导致下风方向城市湍能、湍流扩散系数的明显减小。（4）备用地变成其它几种下垫面类型都对城市气象环境存在一定影响，但是其影响的程度比变成水域带来的影响程度都要小很多。
We simulate meteorological environment of a little town （20 km× 18.6 km） using the Urban Boundary Layer Model developed by Nanjing University. The model s horizontal grid space is very fine （100 m× 100 m）. The simulated results show that the most distinction about PBL structure between big city and little town is that the difference of temperature between city and rural is very small about 0. 1 0.2℃, in another word, there is no heat island in little town. There are greater differences between The TKE profiles and potential temperature profiles of urban area and crop area and residence area in daytime while in nighttime there is about no difference. We design four sensible tests changing surface type of certain area in little town, such as building airport or residence area or artificial lake or high buildings in tested area. Results show that. The local urban planning affects urban meteorological environment in daytime while slightly in nighttime. When tested area is changed high buildings or residence zone, there are phenomena of temperature arising and wind speed decreasing in the city sitting in tested area s downstream, When tested area is built artificial lake or airport, there are contrary phenomena in the city sitting in tested area s downstream. In these four sensitive tests, man-made lake has great effects on downstream city while others have small effects. Through these analysis, we offer the department of urban planning some advantageous advise.. （1）It＇s not well-chosen to develop high buildings or residence area in the city＇s upstream. （2）In order to enhance city airing, building artificial lake at the city＇s upstream is a very good idea. But these conclusions are not general, and it＇s very necessary to further research relationship between tract of teated area and affected degree in downstream.
出处
《高原气象》
CSCD
北大核心
2007年第2期363-372,共10页
Plateau Meteorology
基金
国家自然科学基金重点项目(40333027)资助
关键词
城市边界层
城市布局
数值模式
数值试验
气象环境
Urban boundary layer
Urban planning
Numerical model
Numerical exprement
Meteorological environment
