北疆地区城市化对地面气温趋势估算影响的特殊性

城市化对我国大部分气象站地面气温观测记录都造成了额外的增温,即引起气温观测趋势的正向偏差,但先前研究表明北疆地区城市化可能引起国家站和城市站地面气温出现变凉趋势。为了深入了解这个问题,本文利用前期研究发展的气温参考站数据集和相关分析方法,对北疆地区基准、基本站网和4个代表性城镇站记录的地面气温序列趋势变化特征进行了比较分析,探讨了造成这一特殊现象的可能原因。分析表明证实,北疆地区城镇站和基准、基本站与全国其他地区的相比,其城市化影响表现为明显的气温负趋势,基准、基本站年平均城市化影响达到-0.05℃/10a,城市化贡献为-14.1%,春、夏和秋季城市化影响均为显著的负趋势,秋季最为明显,冬季城市化影响表现出不显著的正趋势；乌苏、石河子、克拉玛依和乌鲁木齐四个城镇站年平均城市化影响介于-0.07~-0.19℃/10a,城市化贡献率介于23.3~100%。本文分析结果有助于深入理解干燥区城市化对地面气温观测序列影响的特殊性及其可能原因,对于区域气候变化检测和归因以及干燥区城市化和绿洲化气候效应研究有一定借鉴意义。

Peculiarity of urbanization effect on surface air temperature trends over northern Xinjiang

Urbanization has caused additional warming in the surface air temperature records of most meteorological stations in China, leading to a positive bias in the air temperature observation trends. However, previous studies have shown that urbanization in northern Xinjiang may have caused a cooling trend in the air temperature data series at national stations and urban stations. In order to gain a deeper understanding of this issue, this article uses the dataset of reference stations and related analysis methods developed in previous research to compare and analyze the trend changes of surface air temperature series at the national station network and four representative urban stations in northern Xinjiang, and discuss the possible reasons for this special phenomenon. The analysis shows that, compared with other regions in China, urbanization effect of urban stations and the national stations in the northern Xinjiang region registers a significant negative trend in air temperature. The annual mean urbanization effect at the national stations reaches -0.05℃/10a, with a urbanization contribution of 14.1%. The urbanization effects in spring, summer, and autumn are all significantly negative, with that of autumn being the most significant. The urbanization effect in winter shows an insignificant positive trend. The annual mean urbanization effect at the four urban stations of Wusu, Shihezi, Karamay and Urumqi ranges from -0.07 to -0.19℃/10a, and the urbanization contributions ranges from 23.3% to 100%. The analysis results of this article contribute to a deeper understanding of the particularity and possible reasons of the urbanization effect in arid areas, and have certain reference significance for detection and attribution of regional climate change, as well as research on the climate effects of urbanization and oasis in the arid areas.