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Arid Land Geography ›› 2021, Vol. 44 ›› Issue (1): 118-130.doi: 10.12118/j.issn.1000–6060.2021.01.13

• Earth Surface Process • Previous Articles     Next Articles

Spatiotemporal variations of the summer daytime surface urban heat island of oasis city in arid area based on FSDAF model

WANG Shuang(),WANG Chengwu(),ZHANG Feiyun   

  1. School of Management, Xinjiang Agricultural University, Urumqi 830052, Xinjiang, China
  • Received:2020-05-06 Revised:2020-06-27 Online:2021-01-25 Published:2021-03-09
  • Contact: Chengwu WANG E-mail:tvxq928@163.com;wcwjgxy@126.com

Abstract:

The urban heat island effect and ecological and environmental problems of an oasis city in an arid area resulting from the acceleration of the global urbanization process have become one of the current research hotspots worldwide. As a critical parameter in investigating the surface urban heat island (SUHI), the land surface temperature (LST) retrieved from thermal infrared images is, to some extent, inaccurate because there is no single sensor that can capture real-time LST at both high spatial and temporal resolutions. This paper used the flexible spatiotemporal data fusion method to generate high spatiotemporal resolution summer daytime LST data in 2001, 2011, and 2018. Spatiotemporal variations of the summer daytime SUHI over Urumqi, an oasis city in the arid area of western China, were assessed based on several urban surface biophysical variables. The results show that the SUHI intensity (SUHII) in Urumqi during the study period was calculated using two indicators of SUHII1 (the urban and smaller rural area difference in the average LST) and SUHII2 (the urban and larger rural area difference in the average LST). Significantly increasing trends of SUHII in the study area were observed. SUHII1 increased from 1.24 °C in 2001 to 2.36 °C in 2011 and 2.83 °C in 2018, whereas SUHII2 increased from 1.44 °C to 2.58 °C and 2.88 °C in the same periods. The highest and lowest summer daytime LST values were observed over areas of bare soil and water, respectively. The distribution of the summer daytime LST correlated positively with the albedo, the impervious surface area, and it correlated negatively with the enhanced vegetation index and fractional vegetation cover. The results emphasize the role of bare soils in aggravating the SUHI in cities in arid areas. Finally, we find that in oasis cities in arid areas, such as Urumqi, although increasing the amount of vegetation covering the urban area may be an effective way to mitigate the SUHI, more profuse vegetation coverage within a larger rural area will increase the SUHII during the summer daytime.

Key words: surface urban heat island, spatiotemporal fusion model, oasis city in arid area