WGDWS生成气象数据模拟北方冬小麦生长效果评价

    Evaluation of the effect of meteorological data generated by WGDWS to simulate the growth of Northern winter wheat

    • 摘要: 作物生长模型可以预测不同尺度从站点到区域级别的作物生长和发育,需要逐日天气数据来驱动,随机天气发生器(stochastic weather simulator,SWG)可以满足这一数据需求。课题组根据中国气候特点构建了基于干湿期的随机天气发生器(weather generator based on dry and wet spells,WGDWS),并复现了应用广泛的WGEN(weather generator)类天气发生器(daily weather stochastic simulator,DWSS)。为了评估WGDWS和DWSS生成气象数据作为小麦生长模型输入的适用性,该研究利用中国北方冬麦区8个站点实测57 a逐日气象数据,通过WGDWS和DWSS分别生成300a逐日气象数据,分析两类发生器生成气象要素统计值的质量。结果表明:除山西太原站点外,两类发生器生成的月均最高温、最低温与实测值达到非常好的一致性,太阳总辐射月均值一致性较好,虽然与实测值有一定偏差,但两类发生器生成气象要素月均值与实测值之间均未达到显著性差异。采用作物模型小麦智能决策系统,分别以实测和两类发生器生成数据作为天气输入,评价两种生产管理方式对小麦生长模拟结果的影响。结果表明,WGDWS和DWSS生成数据对小麦产量和生物量均值模拟效果较好,与实测数据模拟值的决定系数分别达到0.94和0.99。总体而言两类发生器对生物量的模拟效果优于产量,模拟生物量的年际变化也小于产量。WGDWS和DWSS对积温、蒸散量和生物量积累的模拟变化趋势高度一致,与实测数据模拟值均未达到差异显著性。两类发生器相比较,除生物量以外,WGDWS模拟生理指标的平均相对误差(mean relative error,MRE)和均方根误差(root mean square error,RMSE)均小于DWSS,WGDWS模拟产量、生物量5%误差以内占比分别比DWSS高6%和25%。进一步分析两种管理方式下WGDWS和DWSS对产量、生物量、物候期等指标的模拟结果,绝对误差和标准差WGDWS优于DWSS的组数分别为63租和57组(总组数均为88组)。两种管理方式下,有14个指标两类发生器之间有显著性差异,其中13个指标WGDWS显著优于DWSS,说明WGDWS比DWSS具有更好的模拟效果。因此WGDWS生成的气象数据完全可用于作物生长模型的天气输入,并且对产量、生物量等指标的模拟性能要优于DWSS。

       

      Abstract: Crop growth models can be used to predict crop growth and development at different scales, particularly from the station to the regional level. Daily weather data is often required to drive crop growth. The stochastic weather simulator (SWG) can fully meet this demand at present. The research team has constructed a random weather generator, according to the characteristics of China's climate (weather generator using dry and wet spells, WGDWS), in order to replicate the widely-used WGEN series weather generator (daily weather stochastic simulator, daily weather stochastic simulator DWSS). This study aims to evaluate the meteorological data generated by WGDWS and DWSS as the inputs for the wheat growth models. The 57a of daily meteorological data was measured at 8 stations in the northern winter wheat region of China. Then, 300a of daily meteorological data was generated using WGDWS and DWSS generators. The quality of the meteorological element statistical data was also evaluated after generation. Except for the Taiyuan station in Shanxi, the monthly average highest and lowest temperatures were achieved in excellent consistency with the measured values. The monthly average of the total solar radiation showed better consistency, with only the relatively small deviations from the measured values. There was no significant difference between the monthly mean values of the meteorological elements and the measured ones. The overestimation and underestimation of the monthly average rainfall were also found during this time. A crop model wheat intelligent decision-making system was used to evaluate the impact of the measured and generated data on the wheat growth simulation under two treatments (potential production and experience water and fertilizer). The results showed that there was a slight overestimation in the mean wheat yield and biomass that was simulated by WGDWS and DWSS. The better performance of the simulation was achieved, with the determination coefficients of 0.94 and 0.99, respectively, compared with the measured values. In terms of the standard deviation to simulate the yield and biomass, the WGDWS was 13% and 44% lower than the measured weather by more than 20%. In DWSS, these values were 6% and 25%, respectively. Once the standard deviation was more than 10% lower than the actual measurement, WGDWS accounted for 50% and 63%, respectively, while DWSS accounted for 31% and 56%, respectively. Overall, the better simulation was observed on the biomass than on the yield. The interannual variation of the simulated biomass was also smaller than that of the simulated yield. There was a highly consistent simulation of the WGDWS and DWSS for the accumulated temperature, evapotranspiration, and dry matter accumulation. The simulation differences for the accumulated evapotranspiration were slightly greater than those for the accumulated temperature and dry matter. There was no significant difference in the yield and biomass from the measured values. Therefore, the weather data was used instead of the measured values for the wheat growth simulation. The average relative error (MRE) and root mean square error (RMSE) of the physiological indicators simulated by WGDWS were smaller than those of the DWSS, except for the dry matter weight. Compared with the DWSS, the differences in yield and biomass simulated by WGDWS are almost below 10%, with the errors of 10%, accounting for 94% and 100%, respectively. The WGDWS presented a 6% and 25% higher simulated yield and biomass with an error of less than 5%. The better simulation was achieved in the yield, biomass, and phenological period using WGDWS and DWSS. Results showed that the absolute error and standard deviation of the WGDWS were 63 and 57 sets, respectively, with the WGDWS superior to DWSS. There were 14 indicators with significant differences between the two types of generators. Among them, only 1 indicator was DWSS better than that of the WGDWS, indicating that the better simulation of the WGDWS than the DWSS. Therefore, the meteorological data generated by WGDWS was fully used as the input for the crop growth models. There were relatively low simulation errors of the indicators, such as the yield and biomass.

       

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