【作者】 赵静；

【导师】 张继权；

【作者基本信息】 东北师范大学 ， 环境科学， 2020， 硕士

【摘要】 东北地区作为我国玉米主产区之一,位于中高纬度的气候脆弱带,面临严峻的气候变化挑战。近年来,全球气候变暖促使中高纬度地区热量增加,部分地区为了追求高产盲目北移种植中晚熟玉米品种,而气候波动性增强导致气象灾害潜在威胁加剧。受全球气候变暖影响,未来极端气象灾害可能出现频发、重发的趋势,其中低温冷害在21世纪局地发生频率呈增加趋势,将给区域粮食安全带来极大风险。因此,关注东北地区玉米种植界限的变迁以及气候变化背景下冷害风险规律,可以为粮食安全布局提供理论借鉴。本研究以东北玉米低温冷害为研究对象,基于积温指标表征不同品种的种植界限,利用气象观测数据及统计数据揭示种植界限的变迁规律及冷害影响。首先利用Mann-Kendall检验法、气候倾向率等数理统计方法分析玉米种植界限变迁特征;从风险形成要素危险性与脆弱性两方面构建冷害风险评估模型,通过缓冲区界定冷害风险影响范围;最后,预估RCP4.5、RCP8.5排放情景下界限变迁及冷害风险,利用曲面拟合模拟种植界限-冷害风险变化。主要研究结论如下:(1)近60年来,东北地区增温显著,不同品种玉米种植界限呈现北移东扩趋势,其中中晚熟品种界限变化影响区域最为广泛,同时该区域内玉米实际种植面积变化率呈现显著增加趋势;基于≥10℃界限指标计算的潜在玉米播种面积与实际种植面积显著相关,表现出10年的滞后期。(2)历史时期玉米冷害风险特征表现为:冷害危险性呈现波动降低趋势,空间上由北向南降低;高敏感性区逐步北移,同时潜在种植面积与实际种植面积不断增加,区域暴露性增强,北方区域的适应能力提高。综合分析得出1980-2017年冷害风险的中高值区逐渐由中西部向北部地区延伸,基本与玉米界限北移趋势吻合,且界限变化几何中线附近20～40 km范围内受冷害风险威胁较高。(3)对比不同排放路径下界限变化与冷害风险预估:晚熟品种界限在增温减缓期较增温显著期出现小幅度南移现象,受潜在播种面积10年的滞后影响,减缓期暴露性增加;因而减缓期冷害风险较显著期要高出0.06～0.09,减产率增加0.04～0.05,且RCP8.5排放路径下风险增加更为明显;曲面拟合结果显示界限-风险北移趋势显著,高纬度地区成为冷害风险增加显著区,拟合效果良好。本研究弥补了气候变化影响作物种植布局及灾害风险评估研究基础的不足,针对东北地区玉米种植界限变迁影响及冷害风险研究,以期为区域作物布局及保障粮食安全提供理论基础。更多还原

【Abstract】 As one of the main corn-producing areas in China,northeast China is located in the fragile climate zone of middle and high latitudes and faces the severe challenge of climate change.In recent years,global climate warming has increased the heat in the middle and high latitudes,and some regions have blindly moved north to plant medium and late maturing maize varieties in pursuit of high yield.However,the increase in climate volatility has led to the aggravation of the potential threat of meteorological disasters.Affected by global warming,extreme meteorological disasters may occur frequently and recur in the future,among which chilling injury has shown an increasing frequency in local areas since the 21 st century,which will bring great risks to regional food security.Therefore,paying attention to the change of maize planting boundary in northeast China and the law of chilling risk under the background of climate change can provide theoretical reference for the distribution of food security.In this research,the chilling injury of maize in northeast China was taken as the research object,based on the accumulated temperature index to represent the planting limits of different varieties,meteorological observation data,and statistical data were used reveal the changing rules of planting boundaries and the chilling effects.Firstly,mathematical-statistical methods such as the mann-kendall test and climate trend rate were used to analyze the characteristics of maize planting boundary change;The risk assessment model of chilling injury was constructed from the hazard and vulnerability of risk forming factors,and the influence scope of the chilling risk was defined by buffer zone;Finally,the boundary change and chilling injury risk were estimated under the emission scenarios of RCP4.5 and RCP8.5,and the variation of planting boundarychilling injury risk was simulated by using surface fitting.The main results are as follows:(1)In the past 60 years,the temperature in northeast China has increased significantly,and the planting boundaries of different varieties of corn have shifted from north to east.Among them,the boundary changes of middle and late varieties have affected the most extensive areas,and the actual planting area change rate of corn in this region has shown a significant trend of increase.The potential maize planting area calculated based on the threshold index ≥10℃ was significantly correlated with the actual planting area,showing a lag period of 10 years.(2)The characteristics of corn chilling injury risk in the historical period are as follows: the corn chilling injury risk in northeast China shows a decreasing trend in time and gradually decreases from north to south in space;meanwhile,the potential planting area and the actual planting area are increasing,the regional exposure is enhanced,and the adaptability of the northern region is also improving.According to the comprehensive analysis,from 1980 to 2017,the middle and high value areas of cold damage risk gradually extended from the central and western regions to the northern regions,which coincided with the northward trend of maize planting limit,and the cold damage risk was relatively high within 20-40 km of the geometric centerline of the limit change.(3)Comparison of the boundary change and the cold damage risk estimation under different emission paths: the late variety boundary showed a small southward shift in the warming slowing period compared with the significant warming period,and the exposure of maize in the warming slowing period was increased due to the 10-year lag of the potential planting area;Therefore,the risk of chilling injury in the warming slowing period is 0.06～0.09 higher than that in the significant warming period,which will lead to an increase in the reduction rate by 0.04～0.05,and a more significant increase in the risk in the RCP8.5 emission path;The simulation of surface fitting shows that the trend of boundary-risk shifting to the north is significant,and the high latitude area becomes the area with the significant increase of chilling injury risk,and the fitting effect is good.This study makes up for the lack of research foundations for the impact of climate change on crop distribution and disaster risk assessment,and reveals the impact of changes in corn planting boundaries and cold damage risk in Northeast China,to provide a theoretical basis for regional crop distribution and ensuring food security.更多还原