基于基准台站及加密台站的华北平原冬小麦水分亏缺对比分析

Effects of Station Density on the Spatial-Temporal Distribution of Water Deficit in the North China Plain

采用1961-2010年华北平原地区379个加密台站(325个一般台站及54个基准台站)的气象数据,分别计算并分析基于加密台站(即所有气象台站)和基准台站的冬小麦生育期降水量、参考作物蒸散ET0、作物水分亏缺率的时空分布状况。结果表明:(1)应用两种不同密度的气象资料计算所得近50a华北平原冬小麦生育期降水量变化趋势较一致,但基于加密台站的结果低于基准台站10%左右;计算所得生育期降水量在空间分布上整体趋势较为一致,均大致呈纬向分布,由北向南降水量逐渐增大,但在河南西部和南部多山地带存在较明显的差异。(2)参考作物蒸散ET0在1961-2010年整体均呈明显下降趋势,但基于基准台站数据所得ET0大于加密台站6%左右,且差异随时间推移逐渐增大,20世纪90年代差异达11%左右;基于两种台站数据所得生育期ET0空间分布趋势较为一致,均随着纬度的升高而增大,但基于加密台站数据所得ET0高值区(>650mm)与低值区(<450mm)普遍小于基准台站,且加密台站所得ET0普遍小于基准台站,在河南西部、山东西部、河北中部等区域其差异尤为明显。(3)基于两种气象资料得到的近50a作物水分亏缺率整体变化趋势较为一致,相关系数高达0.947,但数值上存在一定差异,在1980年以前加密台站得到的结果大于基准台站,而1980年之后则相反,两个阶段的平均差异均在12%左右;生育期作物水分亏缺率的空间分布趋势基本一致,除河北东北部外,大致趋势为随纬度升高而增大,但加密台站得到的作物水分亏缺率普遍小于基准台站,且以燕山山脉、太行山山脉等山前平原以及泰山周围的差异更为突出。研究说明,目前利用基准台站所进行的华北冬小麦水分时空分布特征分析结果基本可靠,但实际农业生产决策时,华北山前平原及泰山附近区域的研究结果应谨慎参考。

The possible difference of temporal-spatial variation characteristics of soil moisture conditions caused by calculating with different meteorological data sets was explored in this study, to identify the effect of two type of data sets, one from all of the meteorological stations and another only the standard stations, on the calculation results of temporal and spatial rainfall amount, crop evapotranspiration and crop water deficit during growth periods of winter wheat in the North China Plain. The results showed that,（1） annual average precipitation in growth period of winter wheat in North China Plain showed an unobvious trend from 1960 s to 2010 s, and reference crop evapotranspiration showed a trend of decrease, while the crop water deficit rate declined and had a larger difference in inter-decadal variation;（2）The precipitation, reference crop evapotranspiration and crop water deficit rate were in obviously latitudinal distribution. The precipitation decreased with the increase in latitude, accordingly, the reference crop evapotranspiration increased as well as the crop water deficit rate due to low precipitation. Compared with the results based on data from the standard stations, in terms of time variation, the change trend is relatively consistent. However, from the point of value, the average precipitation and reference crop evapotranspiration of standard stations were higher than all stations. Generally speaking, the spatial distributions based on both are consistent, but there is large difference in some terrain areas, which have bigger variability.