温度植被干旱指数在2000-2015年松嫩平原土壤湿度中的应用

选取了时间序列良好的MODIS影像，对松嫩平原2000-2015年逐月的温度植被干旱指数（TVDI）进行计算，并结合农业气象站点的相对土壤湿度数据进行对比验证，发现TVDI和相对土壤湿度数据具有良好的相关关系，表明TVDI可以作为表示土壤含水量的指标。重建1 km分辨率的松嫩平原作物生长季（4-10月）表层土壤湿度空间信息数据集，引入集合经验模态分解分析方法探究了松嫩平原土壤湿度的时空变化特征及变化趋势，并探讨了松嫩平原土壤湿度变化对农作物产量的影响。结果表明，近16年来松嫩平原土壤湿度的时间变化趋势是逐渐变湿，土壤湿度的空间变化趋势是由西南向东北逐渐变湿，极端土壤缺水事件频率呈现出增高的趋势。松嫩平原粮食产量和年均土壤湿度水平显著相关说明粮食产量受到年平均土壤湿度的影响显著，不同季相的土壤湿度对粮食产量的影响程度差异较大，夏季土壤湿度对粮食产量的影响尤为明显。

Application of temperature vegetation dryness index in the estimation of soil moisture of the Songnen Plain

In the current study, time-series MODIS images were selected to calculate the monthly temperature vegetation dryness index (TVDI) from 2000 to 2015 of the Songnen Plain. There was a strong correlation between the TVDI value and soil relative moisture, which signified that TVDI could be used as a substitute indicator for soil relative moisture. The spatial dataset for the surface soil moisture during the crop growing season (from April to October) was rebuilt with a 1 km cell size. The temporal and spatial variation characteristics and dynamic trends of soil moisture were analyzed by means of ensemble empirical mode decomposition (EEMD) and the impact of soil moisture on crop yield was discussed. The results showed that soil moisture was gradually increasing from the southwest to northeast in the Songnen Plain in terms of spatial distribution. Regarding temporal changes, soil moisture had increased over the past 16 years, although the frequency of extreme water shortage events had increased. There was a significant correlation between yearly average soil moisture and crop yield, which showed that crop yield was primarily affected by the yearly average soil moisture. Crop yield was affected by soil moisture of different seasons, especially that of summer.