近 30 年东北三省作物物候期特征提取及其对气温变化的响应

Crop phenophases,i.e.the stages of seeding, heading and harvesting, length of growth period, are important features in agro-ecosystems and the pivotal basis for agricultural production, farm management and planning. In addition, crop phenophase is also a critical topic in global climate change research and ecosystem analysis. In this study, the temporal trends and spatial patterns of the major crop phenophases in Northeast China will be illustrated and analyzed over the past 30 years, by using Normalized Difference Vegetation Index (NDVI) ten day composed time-series data, statistical crop records and observed climate station data collected from 1980 to 2010. Firstly, to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination, the software TIMESAT will be used to generate smooth time series of NDVI based on an asymmetric Gaussian function; secondly, the seasonality parameters, such as the start date, the end date and the peak date of the growing season, length of the growing season, is to be defined and extracted from the smoothed NVDI time-series dataset; Thirdly, each of the extracted parameters and the observed agricultural phenophases will be compared and validated by using a scatter plot, respectively. On this basis, the impact mechanism on crop phenophases from both climate change and human activities will be conducted from a comprehensive manner. The gridded results of crop phenophases could be further applied to the spatial evaluation of cropland productivity, the simulation of biogeochemical cycles and the monitoring of agro-ecosystems on a national scale. Meanwhile, the response mechanisms of crop phenophases to thermal conditions may also be applied in the development of adaptive agriculture strategies in the context of future climate changes.

作物物候期作为重要的农业生态系统特征，不仅是农业生产管理与计划决策的重要依据，也是全球变化研究和生态系统分析的重要内容。本研究选择我国粮食主产区的东北三省为研究区，以主要粮食作物（玉米和水稻）的典型物候期（出苗期、抽穗期与成熟期）为研究对象，利用近 30 年的逐旬遥感时序数据、农业气象资料与作物物候观测资料，完善基于时序遥感数据提取作物物候期特征的技术方法，重建作物物候期特征的时空变化过程；综合分析气候因子与人类活动因子对作物物候期特征的影响机制；重点探讨近 30 年东北三省作物典型物候期对农业热量资源特征变化的时空响应。研究结果将提供作物物候期特征的时空分布信息，可应用于大尺度农田生产力估算、生物地球化学循环模拟和农业生态系统监测；对气温变化的响应机制研究结果还可应用于未来气候条件下农业生态系统优化与适应策略拟定。

申请人围绕农业景观格局与过程方向，重点系统开展了农作物空间格局、时空过程和变化机理研究。主要研究工作如下：（1）在像元尺度上建立了全国主要作物时空分布重构数据集，明确了过去30年我国农作物空间格局的变化过程和规律。（2）科学证实了我国水稻空间分布变迁对气候变化的空间响应机理，揭示了不同自然和社会经济因素对水稻空间变化影响的空间差异性与规律性。未来工作将继续围绕农作物空间格局与全球变化的关键科学问题，针对我国东北水稻种植分布北界，深入探讨基于多要素关联的水稻空间适应力综合评价理论与方法。