北京典型城市湿地小气候效应时空变化特征

Spatiotemporal variation in the microclimate effects of typical urban wetland in Beijing

在北京市选择8个典型湿地为研究样本,对水平方向上温、湿度和负氧离子浓度的变化进行测定,研究湿地对城市温度、湿度和负氧离子浓度的影响。结果表明:湿地对城市局部环境具有明显的降温、增湿和增负氧离子浓度的作用,且距离水体越近小气候效应越强,其中温度与距离显著正相关(R2≥0.81,P<0.01),而湿度和负氧离子浓度均与距离显著负相关(R2≥0.83,P<0.01);与距离湿地5 km处观测值相比,湿地最高可以降温4.4℃,增湿12.8%,增加负氧离子浓度27.2%;湖泊湿地对局部环境的降温和增湿效果比河流湿地的降温增湿效应更加明显,两者分别相差大约1℃和5%左右;因此,从城市规划与建设的角度看,在增加湿地面积的同时,也要根据湿地用途相应地考虑不同的湿地类型,使湿地改善城市生态环境的效应得到充分发挥。

To study the effect of wetlands on urban air quality, air temperature, humidity, and negative oxygen ion concentration were monitored along transects from wetland to surrounding landscapes in eight typical wetlands of Beijing. The observed results showed that air temperature increased （R2 〉10.81, P〈0.01） while humidity and negative oxygen ion concentration decreased （R2 〉10.83, P〈0.01） with increasing the distance from wetlands. At locations 5 km away from the wetlands, air temperature was 4.4℃ higher, while humidity and negative oxygen ion concen- tration were 12.8% and 27.2% lower than the values above the wetlands. Moreover, lakes de- pressed air temperature and elevated air humidity of local environment more pronounced than riv- ers, by about 1℃ and 5%, respectively. These results demonstrated that urban wetlands had the potential to improve local air quality. Therefore, it was suggested to construct more wetlands with appropriate types to make best use of the integrated functions of urban wetlands.