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Declining diurnal temperature range in the North China Plain related to environmental changes

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Abstract

The decreases in diurnal temperature range (DTR) observed in most regions are generally linked to the increase in cloud cover. However, declining clouds and rising aerosols observed over the North China Plain (NCP) of China make it elusive to elucidate the underlying mechanisms behind the declining DTR observed in this region. Here, we analyze the changes in DTR characteristics in the NCP based on 54-year surface temperature observations, in combination with collocated environmental variable measurements. Overall, there is a significant declining trend of DTR from 1960 to 2014 at a rate of − 0.12 °C/decade, largely due to a larger increase in minimum temperature during the night. The cloud effect on DTR is further explored by comparing DTR under clear-sky and overcast conditions, which exhibits a distinct annual cycle with a minimum in summer and a maximum in winter. The decreasing rate of DTR under overcast condition is − 0.30 °C/decade, much faster than the rate of − 0.17 °C/decade under clear-sky condition, indicating steady increases in the nighttime warming effect of middle- or high-clouds. Also, the elevated aerosol concentration could contribute to the declining DTR, due to the cooling effect of aerosols. Moreover, the effect induced by sunshine duration and water vapor on DTR cannot be ignored either. All of the aforementioned environmental variables combine to affect the long-term trend of DTR, despite their different roles in modulating DTR. Our findings call for better understanding of the influence of environmental factors on regional climate system at the diurnal timescale.

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Acknowledgements

This study is supported by the National Key R&D Program of China under Grants 2017YFC1501401 and 2016YFA0602003, the National Natural Science Foundation of China under Grants 91544217, 41771399, 91637101, and 41705002, and the Chinese Academy of Meteorological Sciences under Grant 2017Z005. The authors extend sincere gratitude to the Editor and anonymous reviewers for their insightful comments that help improve the manuscript.

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Xue, W., Guo, J., Zhang, Y. et al. Declining diurnal temperature range in the North China Plain related to environmental changes. Clim Dyn 52, 6109–6119 (2019). https://doi.org/10.1007/s00382-018-4505-8

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