Irrigation and urbanization, two widely occurring land-use/land-cover changes, have important influences on regional climate, especially on temperature. The effect of irrigation and urbanization on temperature is separately documented in several studies. However, there are few studies analyzing the combined effects of irrigation and urbanization on temperature.

Dr. SHI Wenjiao, Prof. TAO Fulu and Prof. LIU Jiyuan from the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (IGSNRR, CAS), analyzed the changes in air temperature were in relation to irrigation and urbanization on the Huang-Huai-Hai Plain of China from 1955 to 2007.

The results indicated that irrigation had a significant cooling effect of 0.17–0.20 °C decade^？1 on average daily maximum temperature of the hottest 1, 5, and 30 d of each year on the Huang-Huai-Hai Plain. Compared with the reference conditions, irrigation also indicated a cooling effect of 0.12 °C decade^？1 on summertime daily maximum temperature. Where irrigation interfaced with urbanization, the urbanization warming of extreme daily maximum temperature seemed to only partly counteract the irrigation cooling effect.

The findings of this study deepen our insight into the effects of irrigation and urbanization on temperature dynamics, and the combined implications for regional climate change.

The ralted results have been published in International Journal of Climatology (Wenjiao Shi, Fulu Tao, Jiyuan Liu. Regional temperature change over the Huang-Huai-Hai Plain: The roles of irrigation versus urbanization. International Journal of Climatology, 2014, 34(4): 1181–1195. doi: 10.1002/joc.3755).

This study was supported by the National Program on Key Basic Research Project of China, the National Natural Science Foundation of China and the Strategic Priority Research Program of the Chinese Academy of Sciences.