摘要
为了分析中国农牧交错带植被典型物候期(生长开始日期,生长结束日期和生长季长度)的变化趋势,利用2001-2010年SPOT-VGT NDVI(SPOT-VEGETATION normalized differential vegetation index)数据,基于Savitzky—Golay滤波和动态阈值法,提取了中国北方农牧交错带植被物候期,探讨研究区植被物候期的空间差异和时间变化。研究表明,农牧交错带植被的生长季一般从4月中旬到5月下旬开始,9月下旬至10月下旬结束;从西南部到东北部,植被物候表现出明显的空间差异;农田植被物候期与自然植被略有不同;对研究区10a物候期线性拟合,得出研究区大部分植被覆盖区域生长季开始日期呈现提前趋势,提前日期大约为1～10d左右;除部分地区外,2001-2010年农牧交错带植被生长季结束日期没有明显变化趋势;10a间研究区大部分草地生长季延长,也有一部分地区的生长季出现缩短趋势。研究提取结果与已有的相关研究结果较为一致,可为农牧交错带生态环境评价和保护提供一定的参考。
Vegetation phenology dynamics reflect the response of biosphere to global climate change and terrestrial hydrological cycle mechanism changes. It is connected well to ecosystem primary productivity of terrestrial and carbon cycle. As the best indicator in monitoring the influence of climate on vegetation, plant phenology has become the key point of global change research. The transition zone between cropping area and nomadic area is sensitive to climate change, thus the changes of vegetation phenology in this area has become an essential issue. Based on the Savitzky-Golay filtering and dynamic threshold method, the spatial-temporal pattern of vegetation phenology in farming-pastoral zone in Northern China was analyzed using SPOT-VGT NDVI data from 2001 to 2010. The results showed that vegetation phenology in the study area generally started from mid-April to late May, and ended in late September to late October. The spatial patterns of vegetation phenology were significantly different in study region. Growth stages of vegetation phenology in the southwest started earlier than the northeast, while ended later. Therefore, length of vegetation growth season in the southwest was longer than those in the northeast. However, greenup dates of vegetation in the Yellow River coast were earlier than vegetation in the same latitudinal zone because of the effect of water. Compared with natural vegetation, growth stages of crops were slightly different due to management. To study the trends of inter-annual variations of the SOS and EOS over the study area, linear regressions are fitted to the start of greening and end of season dates for each pixel of the study area from 2001 to 2010. The results showed that start dates of growth stages were advanced approximately 1-10 days in most study areas for all years. However, the end dates of vegetation growing seasons had no significant changes from 2001 to 2010, except for partial areas. In some regions, the length of seasons （LOS） extended, while decreased in other areas. The phenology of vegetation extracted using SPOT-VGT NDVI datasets in this paper was generally concordant with many reported researches. This paper can provide a reference for the evaluation and protection of ecological environment in farming-pastoral zone.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2013年第1期142-150,I0003,共10页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点基础研究发展规划项目(2013CB733405
2010CB950603)
公益性行业(气象)科研专项经费(GYHY201006042)
国家自然科学基金(41201345)
