我国寒区水稻扩张灌溉大幅度增加的背景下，蒸发蒸腾（ET）受全球变暖、灌溉冷却效应及井水增温的影响，其变化不可避免地影响灌溉定额确定、区域水循环以及水资源管理，并关系到粮食安全和水资源战略，也是农业水循环研究中的新问题。本项目以三江平原为研究区域，开展水稻扩张影响下的蒸发蒸腾变化机制研究，内容包括：①定量区分气候变化、灌溉冷却效应和井水增温等多因子变化引起的参考作物腾发量（ETo）变化，揭示多因子对ETo的协同影响规律；②开展稻田水热耦合平衡试验，比较基于互补相关原理的区域ET模型，计算不同时空尺度ET，阐明ET变化机制；③耦合区域气候模式（WRF）和陆面过程模式（CLM），预测灌溉扩张影响下未来ET变化，提出应对考虑气候变化和人类活动影响下的综合适应性调控策略。研究成果将有助于理解和解决我国东北节水增粮行动技术瓶颈背后的核心科学问题，对于保障区域水资源可持续高效利用和粮食安全具有重要意义。

In the cold region of China, rice paddy area expanded and irrigation water use increased alarmingly. Evapotranspiration is affected by global warming, irrigation-induced cooling effect and heating of groundwater, and it unavoidably influences the determination of irrigation quota, regional water cycling and water resources management, and thus is related to food security and water resources strategy, which is also a new issue in regional climate and interactions between water cycling and human activities. Taking Sanjiang Plain as study area, this project investigates the mechanism of evapotranspiration change as affected by expansion of paddy rice. Detailed contents are as follows: ① The contribution to changes in reference crop evapotranspiration (ETo) from climate change, irrigation-induced cooling effect and heating of groundwater will be quantified, and the multi-factor co-variation patterns of ETo will be analyzed. ② Coupled rice paddy water-heat balance experiment will be conducted, meanwhile, complementary relationship based ET models will be compared to estimate ET of different spatiotemporal scales, and the mechanism of ET change will be revealed.③ Regional climate model and land surface model will be coupled to predict the future change in ET under the influence of rice paddy expansion, and comprehensive adaptation strategies to will be proposed by considering climate change and human activity. This study will be of great significance towards better understanding and solving the scientific problems behind the technological bottleneck of Water-saving and Food-increasing Action in Northeast and thus ensuring food security and regional water resources high-efficiency utilization.