呼伦贝尔草原植被物候对积雪物候的响应机制研究

In this research, in light of the scientific issue that how snow phenology changes affect the vegetation phenology, this project considers the Hulunbuir grassland as the research object to build remote sensing inversion models of snow phenology and vegetation phenology parameters under different scales and to carry out the cross validation by combining the ground experiment, remote sensing inversion and model simulation, realizing the the extraction of snow phenology and vegetation phenology parameters of high, medium and low resolutions. It comprehensively evaluates the temporal and spatial variations of the snow phenology and vegetation phenology as well as their responses to regional and global climate changes in the past thirty years by using the methods of comparative analysis, trend detection, spatial statistics, regression analysis, correlation analysis and principal component analysis, and conducts a multi-angle quantitative analysis of the influence mechanism of the snow phenology on the vegetation phenology. The project is expected to reveal the response mechanisms of the site scale, pixel scale and regional scale grassland phenology to the snow phenology, and clarify the quantitative relationship between the snow phenology and the vegetation phenology, revealing the influence law of the short-, medium- and long-term snow phenology on the vegetation phenology due to future climate changes. The research results of the project have important scientific reference value and theoretical reference significance to understand the regional and global climate changes. It is also of great importance to evaluate and forecast the impact of future climate changes on the grassland vegetation phenology, providing a scientific basis to the pasture management, sustainable development, disaster prevention and mitigation of grasslands.

针对积雪物候如何影响植被物候的科学问题，本项目拟以呼伦贝尔草原为研究对象，采用地面实验、遥感反演和模型模拟相结合的研究方法，建立不同尺度积雪物候和植被物候遥感反演模型并进行交叉验证，实现高、中、低分辨率积雪物候和植被物候参数反演。采用对比分析、趋势检测、空间统计、回归分析、相关分析和主成分分析等方法，综合评估过去30年来积雪物候和植被物候的时空变化规律以及对区域和全球气候变化的响应特征，多角度定量化研究植被物候对积雪物候的响应机理。项目预期揭示站点尺度、像元尺度和区域尺度草原植被物候对积雪物候的响应机制，阐明积雪物候与植被物候之间的定量关系，揭示未来气候变化情景下短、中、长期积雪物候对植被物候的影响规律。项目的研究成果对理解区域和全球气候变化具有重要科学参考价值和理论借鉴意义，为评估和应对未来气候变化对草原植被物候的影响提供理论依据，为草原的牧业管理、可持续发展和防灾减灾等提供科学依据。

全球气候变化已经带来积雪物候的变化，积雪物候的变化对植被物候变化会产生一定影响。东北地区处于中国的最北端，被季节性积雪覆盖，是中国三大积雪区之一，在气候变化的背景下，积雪物候是怎么影响植被物候变化的科学问题还不明晰。为了评估正在进行的气候变化对草原生态系统的影响，有必要将植被物候对积雪物候的响应机制展开研究。在此背景下，本项目主要探索了积雪物候和植被物候参数遥感反演模型和方法；研究了呼伦贝尔草原不同尺度积雪物候和植被物候时空变化特征；研究了积雪物候和植被物候对区域气候和全球气候变化的响应特征；研究了积雪物候与植被物候的作用关系；研究了积雪物候和植被物候对气候参数的敏感性特征；量化了积雪物候对草原植被物候影响的相对贡献；研究了未来气候变化情景下积雪物候对植被物候的影响。取得了一些列重要结果，主要体现在通过多源遥感和多模型以及多提取方法想结合的思路，结合地面观测数据获得了呼伦贝尔地区高时空分辨率遥感反演结果，减少了尺度效应。量化了呼伦贝尔地区积雪物候和植被时候的时空特征；明晰了呼伦贝尔草原植被物候和积雪物候对气候的响应规律；掌握了积雪物候对植被物候的作用规律；探索出呼伦贝尔草原物候对温度参数敏感性阈值；模拟预测出了未来100年里研究区植被物候和积雪物候特征。通过四年的研究，在物候遥感反演、积雪物候参数反演、地面观测实验等方面积累了大量数据和相关经验模型，为其他相关研究提供借鉴。研究结果对理解区域和全球气候变化具有重要科学参考价值和理论借鉴意义，对评估和预测未来气候变化对草原植被物候的影响具有重要意义，还可为进一步制定应对气候变化政策提供科学基础。