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| 应用Morlet评估不同生育时期干旱对小麦单产的影响 |
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王鹏新1,2,冯明悦2,3,梅树立1,2,张树誉4,李红梅4
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1.中国农业大学信息与电气工程学院，北京100083;2.农业农村部农业灾害遥感重点实验室，北京100083;3.中科三清科技有限公司，北京100083;4.陕西省气象局，西安710014
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| 摘要: |
| 目的 干旱是关中平原主要的农业灾害之一，分析关中平原作物不同生育时期干旱的演变规律及其对产量的影响程度可为抗旱减灾及作物稳产提供参考依据。方法 基于关中平原2008—2013年的小麦单产数据和条件植被温度指数（VTCI）的干旱监测结果，采用小波功率谱和交叉小波功率谱作为特征时间尺度的度量指标，确定冬小麦各生育时期干旱对单产的影响程度，并构建小麦主要生育期的加权VTCI与单产间的线性回归模型。结果 冬小麦单产与主要生育期VTCI的共振周期与各生育时期VTCI的主振荡周期类似；基于共振周期和主振荡周期确定的特征时间尺度，通过小波互相关度赋予的权重均能够反映冬小麦各生育时期干旱对其单产影响的相对重要程度，得到的加权VTCI与单产间的线性回归方程均达到极显著水平，对应单产模型的估测单产与实测单产的均方根误差分别为328.3 kg · hm-2和344.8 kg · hm-2。结论 小波功率谱可用于分析作物不同生育时期干旱对其产量的影响，且拔节期干旱对小麦产量的影响最大，抽穗—灌浆期次之，乳熟期和返青期依次递减。 |
| 关键词: 条件植被温度指数 干旱影响评估 小波互相关度 功率谱 Morlet |
| DOI：10.12105/j.issn.1672-0423.20180301 |
| 分类号: |
| 基金项目:国家自然科学基金项目41371390，41871336;中国农业大学基本科研业务费专项资金项目2018XD002国家自然科学基金项目（41371390，41871336）；中国农业大学基本科研业务费专项资金项目（2018XD002） |
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| Assessment of droughts at different growth stages on winter wheat yield using the Morlet |
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Wang Pengxin1,2,Feng Mingyue2,3,Mei Shuli1,2,Zhang Shuyu4,Li Hongmei4
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1.College of Information and Electrical Engineering，China Agricultural University，Beijing 100083，China;2.Key Laboratory of Remote Sensing for Agri-Hazards，Ministry of Agriculture and Rural Affairs，Beijing 100083，China;3.Clear Technology Co. ，Ltd. ，Beijing 100083，China;4.Shaanxi Provincial Meteorological Bureau，Xi’an 710014，China
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| Abstract: |
| Purpose Drought is one of the most important agricultural disasters in the Guanzhong Plain，therefore，analyzing occurrence characteristics of droughts and their relative importance at the main growth stages on wheat yields can provide reference for drought mitigation and maintaining stable yield.Method Based on collected winter wheat yields in the years of 2008—2013 in the Plain and remotely sensed vegetation temperature condition index （VTCI），the wavelet and cross-wavelet were applied as multi-scale analysis tools for calculating the wavelet power spectra and cross wavelet power spectra at different time scales，and oscillation energy power distribution of a single time series and the correlations between the VTCIs at the main growth stages of winter wheat and wheat yields were analyzed in the time-frequency domain. Drought impact degrees at different growth stages to wheat yield，denoted as the wavelet cross-correlation degree （WCCD），were determined by using the correlations in the time-frequency domain，and linear regression models between the weights of VTCI at the main growth stages and wheat yields were established.Result The results showed that the resonance periods between VTCIs at the 4 growth stages and yields were similar to the main oscillation periods of the time series VTCIs at the four growth stages. The WCCD，which was determined by the wavelet cross-correlation coefficients of main oscillation periods and resonance periods，could reflect relative importance of droughts at the main growth stages on wheat yields. Based on the resonance periods and main oscillation periods，the liner regression equations between the wheat yields were all at the extremely significant level （P<0.001），and the root mean square error between the estimated and measured yields were 328.3 kg · hm-2 and 344.8 kg · hm-2.Conclusion The wavelet power spectrum method can be used to analyze the importance degrees of droughts at different growth stages to wheat yields. The droughts at the jointing stage of wheat had the largest impact on wheat yields，followed by the droughts at the heading-filling stage，and the droughts at the dough stage and the reviving stage had less impact on the wheat yields. |
| Key words: vegetation temperature condition index impact assessment of drought wavelet cross-correlation degree power spectrum Morlet |