中文摘要：

选择长江中下游单季中稻为研究对象,结合45个气象站1961～2010年逐日气象资料,基于统计降尺度模型（SDSM）,生成HadCM3气候模式A2和B2两种情景下各站点参考作物腾发量和降水数据。基于联合国粮食及农业组织（FAO）推荐的作物系数法,并考虑有效性降雨和不同地区深层渗漏量,分析历史和未来的水稻灌溉需水时空变化特征。结果表明：过去50年,除了太湖流域以外的长江中下游大部分区域的参考作物腾发量和水稻需水量都呈显著下降趋势,而显著下降的水稻灌溉需水量主要位于鄱阳湖流域;未来两种情景下,参考作物腾发量、水稻需水量和水稻灌溉需水量均值都呈下降趋势,但水稻灌溉需水量降幅最小;水稻需水量和水稻灌溉需水量在长江中下游地区的变化趋势具有明显的空间异质性,水稻需水量大幅减少的区域由太湖流域向汉江和洞庭湖流域扩展。未来水稻灌溉需水量减少的区域主要分布在太湖流域、汉江流域东部和洞庭湖流域北部,并随时间推移呈扩大趋势。

英文摘要：

Projections of rice irrigation water requirements under future climate conditions can be beneficial in develo- ping adaptation strategies for reducing the negative impact of climate change on rice productions and to ensuring the food security from the perspective of the sustainable use of water resources. Using a statistical downscaling model （SDSM） , the projected daily reference evapotranspiration and precipitation of HadCM3 under A2 and B2 scenarios were downscaled to 45 local meteorological stations in the Mid-Lower Reaches of Yangtze River. Spatiotemporal varia-tions of irrigation water requirements during the middle-season rice growing period for the past five decades （1961-2010） and future dates （2011-2099） were analyzed. The FAO （Food and Agricultural Organization） crop coefficient method and a water balance model considering the effective precipitation and deep percolation were used in the analysis. The results show that in the past five decades, significant decreasing trends in reference crop evapotrans-piration and rice water demand can be detected in most regions of the Mid-Lower Reaches of Yangtze River except the Taihu Basin. While significant decreasing trends in paddy irrigation water requirements can only be observed in the Poyanghu Basin. Under both A2 and B2 scenarios, the mean reference crop evapotranspiration, paddy water demand and irrigation water requirements would decrease. However, the decrease in paddy irrigation water requirements would be greater than that in reference crop evapotranspiration and paddy water demand. Spatial heterogeneities could be found in changing trends in paddy water demand and irrigation water requirement. The region with greater decreasing paddy water demand would extend from the Taihu Basin to the Hanjiang River Basin and the Dongtinghu Basin. The decrease of paddy irrigation water requirements could be expected in the Taihu Basin, the eastern area of the Hanjiang River Basin and the northern area of the Dongtinghu Basin. The region with the dec