马铃薯发育期模型精度及其对升温的敏感性比较

Comparison of simulation accuracy of potato phenology models and their sensitivity to rising temperature

  • 摘要: 马铃薯是世界第四大主粮作物, 马铃薯发育期的准确模拟是评估气候变化对马铃薯生长发育影响的基础。通过研究筛选在全国马铃薯种植区发育期模拟效果最优的模型, 并基于模型探究历史气候变化对马铃薯生育期的影响差异以及模型对升温(1~5℃)的敏感性, 可为模型改进提供方向。针对当前对覆盖不同气候和品种类型的发育期模型综合对比研究较少, 本研究选取3种温度响应函数与2种日长响应函数, 组合形成3种温度模型和6种光温模型, 运用模拟退火算法对模型进行调参, 对比其在全国8个站点模拟马铃薯全生育期的精度, 结果表明: 1)线性温度函数+负指数日长函数光温模型(M3)、Logistic温度函数+负指数日长函数光温模型(M6)和Beta温度函数+负指数日长函数光温模型(M9)的模拟效果最优, 3个模型模拟和观测的全生育期长度RMSE分别为7.7 d、6.8 d和7.1 d, R2均大于0.90。2)基于最优模型在4个代表性站点的模拟结果显示, 历史气候变化导致马铃薯生育期总体呈缩短趋势, 但在不同站点模型间存在差异。3)升温1~5℃, 模型M3和M6模拟的马铃薯全生育期日数呈线性缩短, 每升温1℃, 4个站点的生育期缩短3.0~8.2 d; 而模型M9模拟的全生育期日数呈非线性变化, 随温度升高生育期缩短趋势先增加后减小。筛选出的3种光温模型均可有效模拟马铃薯发育期; 基于3种模型模拟的历史气候变化总体均使马铃薯生育期缩短, 但变化率不同; 温度响应函数的不同, 使得3种模型对升温的敏感性不同, 且模型间差异随着升温而增加。研究结果为马铃薯发育期模型选择和改进提供了重要参考。

     

    Abstract: Potatoes are the fourth largest staple food crop worldwide. The accurate simulation of potato phenology is the basis for assessing the impacts of climate change on potato growth and development. Selecting the optimal potato phenology models across China’s potato planting regions, and exploring the difference in the simulated impact of historical climate change on the potato growth period among these phenology models, as well as their sensitivity to temperature rise (1−5℃), could help provide direction for model improvement. However, there have been few studies on the integrated comparison of potato phenology models across different climate types and cultivars. In this study, three temperature response functions and two day-length response functions were combined into three temperature-based and six light-temperature-based models. The accuracy of the nine models in simulating the length of the potato growth period at eight sites across China’s potato planting regions was compared with the derived model parameters based on a simulated annealing algorithm. The study results showed that: 1) The simulation accuracy of linear function-based temperature with a negative exponential function-based photoperiod-temperature model (M3), logistic function-based temperature with a negative exponential function-based photoperiod-temperature model (M6), and beta function-based temperature with a negative exponential function-based photoperiod-temperature model (M9) had optimal simulation accuracies among the nine phenology models. The root mean square errors (RMSEs) between the observed and simulated lengths of the potato growth period, simulated by M3, M6, and M9, were 7.7 d, 6.8 d, and 7.1 d, respectively (R2>0.90). 2) Based on the three optimal phenology models, the simulation results at the four representative sites showed that historical climate change had decreased the length of the potato growth period, although there were differences between the models at different sites. 3) When the temperature was increased by 1℃ to 5℃, the simulated length of the potato growth period by M3 and M6 were linearly shortened with the decline rate of 3.0–8.2 d per 1℃ rise. With increasing temperature, the shortening trend of the simulated length of the potato growth period by M9 first increased and then decreased. Our study found that the three optimal models could effectively simulate potato phenology across China’s potato planting regions under current climate conditions. All the simulated results, based on the three optimal phenology models, showed that historical climate change shortened the length of the potato growth period, but with different rates of decrease simulated by different models. The photoperiod response function in the phenology models changed the sharpness of the temperature response function and increased the temperature sensitivity of the models. The differences between the models increased with increasing temperature. Our study provides an important reference for the selection and improvement of potato phenology models.

     

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