黄淮海地区冬小麦-夏玉米生育期内水分供需时空变化特征

为明确影响黄淮海地区作物需水的关键气象因子及其变化特征,基于该地区的66个国家标准气象站点1987—2016年长时间序列的逐日观测资料,采用敏感性分析、因子趋势检测和GIS空间分析等方法,定量计算冬小麦-夏玉米生育期内的有效降水量(Pe)、作物需水量(ETc)及灌溉需水量(ETaw),分析1987—2016年黄淮海区冬小麦-夏玉米水分供需的时空变化特征以及ETc对不同气象因子的敏感性差异。研究表明,1987—2016年冬小麦生育期内Pe远不能满足其生长需求,年均ETaw达264mm,特别冬小麦生育期内Pe呈较明显的下降趋势,伴随气温不断升高,使其面临较严重的水分亏缺;而夏玉米生育期与Pe耦合度高,年均ETaw仅为79mm。黄淮海地区北部为冬小麦ETc和ETaw的高值区,南部ETaw相对较低,但1987—2016年增加趋势明显。相对湿度和气温对ETc的影响最大,其次是平均风速和日照时数,相对湿度的减少和气温的显著升高都将导致ETc的增加。

Spatial and temporal characteristics of water supply-demand during the development of winter wheat-summer maize in the Huang-Huai-Hai region

In order to identify key meteorological factors affecting crop water demand and their changing characters, based on long-term climate data during 1987-2016, this study quantitatively calculated the effective precipitation(P_e), crop water demand(ET_c)and irrigation water demand(ET_aw). The spatio-temporal variation in crop water supply-demand and the main factors that influenced the crop water demand were analyzed by adopting the methods of sensitivity analysis, factor trend detection and GIS spatial analysis. The results indicated that the P_e didn''t meet the water demand of winter wheat in the past 30 years, and the average annual ET_aw was 264 mm. As the temperature continues to rise, especially because of the significant downward trend of P_e in the past 10 years, winter wheat production might face more serious water deficit in future. The P_e was more consistent with the water demand of summer maize, and its ET_aw was only 79 mm. The northern Huang-Huai-Hai was the high-value area of the ET_c and ET_aw of winter wheat, and the ET_aw of the southern part was relatively low but kept increasing obviously over the past 30 years. Relative humidity and temperature had the greatest impact on ET_c, followed by average wind speed and sunshine hours. The reduction of relative humidity and the significant increase in temperature both led to the increase in ET_c.