• Denghua Yan

      Articles written in Journal of Earth System Science

    • Projection of extreme precipitation in the context of climate change in Huang-Huai-Hai region, China

      Jun Yin Denghua Yan Zhiyong Yang Zhe Yuan Yong Yuan Cheng Zhang

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      Based on the national precipitation dataset (0.5$^◦$ × 0.5$^◦$) 1961–2011, published by the National Meteorological Information Center of China and the five Global Climate Models provided by ISI-MIP, annual maximum precipitation for 1 day, 3 days and 7 days could be calculated. Extreme precipitation was fitted via Generalized Extreme Value (GEV) distribution to explore the changes of extreme precipitation with the return period of 20 years and 50 years during 1961–2000 and 2001–2050. Based on this, extreme precipitation projection in Huang-Huai-Hai region was done. The results showed that the five Global Climate Models could simulate the statistical features of extreme precipitation quite well, in which IPSL-CM5A-LR has the highest precision. Simulation of IPSL-CM5A-LR indicates that precipitation with the return period of 20 years and 50 years in the middle reaches of the Yellow River, middle and lower reaches of Huaihe River and plain area of the southern Haihe River will increase considerably in the future. Extreme precipitation in some of the places will even increase by more than 30%, which means that these places will face larger flood risk and their capacity to respond to flood disasters should be improved.

    • Effects of climate change on spring wheat phenophase and water requirement in Heihe River basin, China

      Dongmei Han Denghua Yan Xinyi Xu Yu Gao

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      Climate change has significantly altered the temperature rhythm which is a key factor for the growth and phenophase of the crop. And temperature change further affects crop water requirement and irrigation system. In the north-west of China, one of the most important crop production bases is Heihe River basin where the observed phenological data is scarce. This study thus first adopted accumulated temperature threshold (ATT) method to define the phenological stages of the crop, and analysed the effect of climate change on phenological stages and water requirement of the crop during growing season. The results indicated the ATT was available for the determination of spring wheat phenological stages. The start dates of all phenological stages became earlier and the growing season length (days) was reduced by 7 days under climate change. During the growing season, water requirement without consideration of phenophase change has been increased by 26.1 mm, while that with consideration of phenophase change was featured in the decrease of water requirement by 50 mm. When temperature increased by 1°C on average, the changes were featured in the 2 days early start date of growing season, 2 days decrease of growing season length, and the 1.4 mm increase of water requirement, respectively.

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