Zhang Yue, Li Lin, Wang Hongbin, Zhang Yao, Wang Naijia, Chen Junpeng
College of Resources and Environment, Jilin Agricultural University, Changchun, 130118, China.
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases, Jilin Agricultural University, Changchun, 130118, China.
Environ Monit Assess. 2017 Oct 1;189(11):531. doi: 10.1007/s10661-017-6247-1.
As an important crop growing area, Northeast China (NEC) plays a vital role in China's food security, which has been severely affected by climate change in recent years. Vegetation phenology in this region is sensitive to climate change, and currently, the relationship between the phenology of NEC and climate change remains unclear. In this study, we used a satellite-derived normalized difference vegetation index (NDVI) to obtain the temporal patterns of the land surface phenology in NEC from 2000 to 2015 and validated the results using ground phenology observations. We then explored the relationships among land surface phenology, temperature, precipitation, and sunshine hours for relevant periods. Our results showed that the NEC experienced great phenological changes in terms of spatial heterogeneity during 2000-2015. The spatial patterns of land surface phenology mainly changed with altitude and land cover type. In most regions of NEC, the start date of land surface phenology had advanced by approximately 1.0 days year, and the length of land surface phenology had been prolonged by approximately 1.0 days year except for the needle-leaf and cropland areas, due to the warm conditions. We found that a distinct inter-annual variation in land surface phenology related to climate variables, even if some areas presented non-significant trends. Land surface phenology was coupled with climate variables and distinct responses at different combinations of temperature, precipitation, sunshine hours, altitude, and anthropogenic influence. These findings suggest that remote sensing and our phenology extracting methods hold great potential for helping to understand how land surface phenology is sensitive to global climate change.
作为重要的农作物种植区，中国东北地区对中国的粮食安全起着至关重要的作用，近年来该地区受到气候变化的严重影响。该地区的植被物候对气候变化敏感，目前，东北地区物候与气候变化之间的关系仍不明确。在本研究中，我们利用卫星衍生的归一化植被指数（NDVI）获取了2000年至2015年东北地区陆地表面物候的时间模式，并用地表物候观测数据对结果进行了验证。然后，我们探讨了相关时期陆地表面物候、温度、降水和日照时数之间的关系。我们的结果表明，2000 - 2015年期间，东北地区在物候变化方面存在很大的空间异质性。陆地表面物候的空间格局主要随海拔和土地覆盖类型而变化。在东北地区的大部分地区，由于气候变暖，陆地表面物候的开始日期每年提前约1.0天，陆地表面物候期每年延长约1.0天，但针叶林和农田地区除外。我们发现，即使某些地区呈现不显著的趋势，陆地表面物候与气候变量之间仍存在明显的年际变化。陆地表面物候与气候变量相互关联，在温度、降水、日照时数、海拔和人为影响的不同组合下有不同的响应。这些发现表明，遥感技术和我们的物候提取方法在帮助理解陆地表面物候如何对全球气候变化敏感方面具有巨大潜力。
