耦合城市冠层模型对暴雨模拟精度的影响

Impacts of coupling urban canopy model on storm simulation

城市通过改变大气组成、影响水和能量循环要素以及生态系统等途径对当地以至全球尺度的气候要素都有着重要的影响,对城市中各种能量和动量过程的精细刻画正在成为天气研究和天气预报的重要需求。本文把通过遥感影像Landsat TM提取的城市下垫面不透水率信息引入到城市冠层参数化方案中,基于最新的数值天气模式WRF研究了在数值天气模式中耦合城市冠层模型对暴雨模拟精度的影响。结果表明,相对于单纯的改变城市区域的粗糙度、反射率等参数以反映城市过程的方法,在天气模式的陆面过程描述中耦合城市冠层模型或许可以提高对暴雨落区、降雨量以及最大降雨强度的模拟效果。研究可为改善城市的暴雨研究和预报提供参考。

Urbanization has significant impacts on atmospheric composition on scales from local to global through changing the components of the water and energy cycle and modifying ecosystems. Detailed modeling of energy and momentum processes in the urban regions is increasingly more important to weather research and its forecasting models. This study introduced the impervious ratio extracted from Landsat TM data into the parameterization scheme of an urban canopy model （UCM） , and examined the impacts of coupling UCM on storm simulation accuracy using a bulk parameterization approach within the framework of the state-of-the-art WRF （Weather Research and Forecasting, Version 3.3）. Results indicate that this coupling model could produce some improvement on the simulation of area, volume and maximum intensity of rainfall, in comparison with the bulk parameterization approach considering only the roughness height or albedo of urban area. The results would provide reference for further study in urban storm research and forecasting.