Estimating the effect of urbanization on extreme climate events in the Beijing-Tianjin-Hebei region, China

Na Zhao; Yimeng Jiao; Ting Ma; Miaomiao Zhao; Zemeng Fan; Xiaozhe Yin; Yu Liu; Tianxiang Yue

doi:10.1016/j.scitotenv.2019.06.374

Estimating the effect of urbanization on extreme climate events in the Beijing-Tianjin-Hebei region, China

Sci Total Environ. 2019 Oct 20:688:1005-1015. doi: 10.1016/j.scitotenv.2019.06.374. Epub 2019 Jun 25.

Authors

Na Zhao¹, Yimeng Jiao², Ting Ma², Miaomiao Zhao², Zemeng Fan², Xiaozhe Yin³, Yu Liu², Tianxiang Yue²

Affiliations

¹ State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100101, China; Jiangsu Center for Collaborative Innovation in Geographic Information Resource Development and Application, Nanjing 210023, China. Electronic address: zhaon@lreis.ac.cn.
² State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100101, China.
³ Spatial Sciences Institute, Dornsife College of Letters, Arts and Sciences, University of Southern California, United States of America.

PMID: 31726534
DOI: 10.1016/j.scitotenv.2019.06.374

Abstract

Quantifying the impact of urbanization on extreme climate events is significant for ecosystem responses, flood control, and urban planners. This study aimed to examine the urbanization effects on a suite of 36 extreme temperature and precipitation indices for the Beijing-Tianjin-Hebei (BTH) region by classifying the climate observations into three different urbanization levels. A total of 176 meteorological stations were used to identify large cities, small and medium-size cities and rural environments by applying K-means cluster analysis combined with spatial land use, nighttime light remote sensing, socio-economic data and Google Earth. The change trends of the extreme events during 1980-2015 were detected by using Mann-Kendall (MK) statistical test and Sen's slope estimator. Urbanization effects on those extreme events were calculated as well. Results indicated that the cool indices generally showed decreasing trends over the time period 1980-2015, while the warm indices tended to increase. Larger and more significant changes occurred with indices related to the daily minimum temperature. The different change rates of temperature extremes in urban, suburban and rural environments were mainly about the cool and warm night indices. Urbanization in medium-size cities tended to have a negative effect on cool indices, while the urbanization in large cities had a positive effect on warm indices. The significant difference of urbanization effect between large and medium-size cities lay in the daily maximum temperature. Results also demonstrated the scale effect of the urbanization on the extreme temperature events. However, the results showed little evidence of the urban effect on extreme precipitation events in the BTH region. This paper explored the changes in temperature and precipitation extremes and qualified the urbanization effects on those extreme events in the BTH region. The findings of this research can provide new insights into the future urban agglomeration development projects.

Keywords: China; Extreme climate events; K-means algorithm; Mann-Kendall test; Urbanization contribution.