基于作物模型模拟年际生物量变化的冬小麦干旱监测研究

Study on drought monitoring for winter wheat based on variation of biomass simulated by crop model

选择关中平原地区冬小麦为研究对象,在对农业技术转移决策支持系统(DSSAT)中的CERES-Wheat模型进行标定的基础上,根据距平的方法分析了模型模拟的冬小麦生物量的年际变化情况。结果表明:生物量距平为正值时,未发生旱情或旱情不明显;生物量距平为负值时,发生了干旱。据此建立了基于生物量距平的干旱监测模型。通过气象网站的降水量资料对该研究区域2000—2009年每年4月下旬的单点干旱监测结果进行验证,结果表明生物量距平与最近2旬至5旬的累计降水量距平的相关性较高,证实了应用该模型进行干旱监测的可行性和近实时性。将该模型与2000—2009年MODIS每8天的GPP产品相结合,得到了干旱的区域分布结果,结果表明:关中平原在2000、2003年和2007年4月下旬时发生干旱,在其余研究年份4月下旬时未出现旱情。

Based on the calibrated CERES- Wheat model and the anomaly method, the inter-annual variability of biomass of winter wheat in the Guanzhong Plain in Shaanxi Province was simulated. The results showed that when the biomass anomaly was positive, there was no drought or no remarkable drought; when the biomass anomaly was negative, the drought occurred. Accordingly, the drought monitoring model was established based on the biomass anomaly. A lin- ear correlation analysis was applied to study the correlation between the precipitation anomaly and the biomass anomaly, which showed that the biomass anomaly was highly correlated with the cumulative precipitation anomaly in the last 20 - 50 days. This indicated that the model was feasible to be used for the near real-time drought monitoring. Furthermore, the regional drought distribution was analyzed by combining the model with the terrestrial gross primary productivity （GPP） of every 8 days, which was derived from the MOD17A2 data of NASA EOS/MODIS （Terra） from 2000 to 2009. The results showed that the Guanzhong Plain was suffered from drought in the last ten days of April in 2000, 2003 and 2007, while there was no drought in the same period of other study years.