Mapping Local Climate Zone in China’s Major Cities

Progress in urban climate science is severely hindered by the lacuna of globally consistent and coherent information that describes aspects of the form and function of urban morphology at a detailed spatial resolution. The World Urban Database and Access Portal Tools (WUDAPT) project is proposed to solve the above problems, which has adopted the Local Climate Zone (LCZ) scheme as a basic and consistent description of form and function of cities at neighborhood scale. This study aims to develop a LCZ classification map and establish the urban morphology database for climate research and urban planning in China’s major cities. A simple workflow provided by WUDAPT project has been applied to perform this task.

The results from the quality assessments show that the LCZ maps of 63 cities in China are generally of good quality, i.e. 69–92% overall accuracy (OA). In particular, the acceptable accuracy (77-93%) is much higher when considering weights that take the morphological and climatic similarity of certain classes into account. The building height data from surveying of these cities, including of Beijing, shanghai, Changsha, Chongqing, Fuzhou, Qingdao, Lanzhou, Harbin and Lhasa，were used for testing, and a moderate accuracy (at building height) was of 51-68%. Most of buildings heights of LCZ types are in line with the surveying data, except for Compact high-rise (LCZ 1) and Open high-rise (LCZ 4), which is about 20.5±4.7 m, and has slightly lower than the LCZ standard value (>25 m). This is due to insufficient underlying input information on building height, and a general tendency to confuse these two classes with Compact mid-rise (LCZ 2) and Open mid-rise (LCZ 5).

Construction area is a very important type of underlying surface in developing countries like China. For example, in Beijing, Guangzhou and Chongqing, this type accounts for 21%, 9% and 9%, mainly distributed in suburban areas. This is an important urban underlying surface in China, but this underlying surface type has not been defined by Stewart and Oke. A follow-up study will try to define the underlying surface of construction area in LCZ classification system.