陕北黄土高原植被动态变化及其对气候因子的响应

(1.西安科技大学 测绘科学与技术学院,陕西 西安 710054; 2.东莞市城建规划设计院,广东 东莞 523001)

退耕还林还草; 植被覆盖度; 动态变化; 气候响应; 陕北黄土高原

Dynamic changes of vegetation and its responses to climate factors in northern Shaanxi loess plateau region
GUO Li-yu1,GUO Zhao1,2,WANG Tao1,ZHANG Yue1,LI Yu-si1,LIU Ying1

(1.College of Geomatics,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Dongguan Urban Planning and Design Institute,Dongguan 523001,China)

grain for green project; fractional vegetation coverage; dynamic change; impact on climate factors; northern Shaanxi loess plateau

DOI: 10.13800/j.cnki.xakjdxxb.2019.0219

备注

为了研究退耕还林还草工程实施后期,陕北黄土高原地区地表植被变化特征及气候因子对植被变化的影响,采用MODIS NDVI数据,通过像元二分法计算植被覆盖度,结合相关气象站点监测数据,利用线性回归分析、相关系数及显著性检验法,分析了陕北黄土高原植被覆盖度时空变化趋势及其对气温、降水因子的响应。结果 表明:研究区植被覆盖度空间分布差异显著,由北向南植被覆盖度由低向高过渡明显,2009—2016年植被覆盖等级的空间转移变化主要发生在北部和中部地区,表现出由中低植被覆盖向中等植被覆盖转移、中等植被覆盖向中高植被覆盖转移的态势。2009—2016年研究区植被覆盖度年际变化速率较小,整体呈平缓增加趋势,中部和南部部分地区有减少趋势但变化趋势不显著。研究区内年植被覆盖度与年降水量、年平均气温的相关系数、偏相关系数均较小,相关性不显著。不同区域的植被覆盖度对气候因子的响应结果不同,在空间上正负相关性共存,研究区北部受年降水量影响较大,而中部受年平均气温影响较大。研究区植被覆盖度对气候因子的响应存在滞后性,生长季的植被生长受同月降水量和前一月平均气温的影响较大,且绝大部分地区均表现为正向相关。

For the research of the features of surface vegetation change in Northern Shaanxi Loess Plateau and the effect of climate factors on vegetation change during the later stage of the Grain for Green Project(GGP),this paper calculates vegetation coverage by using the MODIS NDVI data and pixel dichotomy method,and comprehensively analyzes the trends of spatio-temporal change for vegetation coverage on the northern Plateau in Shaanxi and its response to temperature and precipitation,based on the meteorology data and related approaches: linear regression analysis,coefficient and significance test.The results indicate that:There is a prominent difference in the spatial distribution of the vegetation coverage in study areas.From North regions to South regions,the vegetation coverage presents an apparent transition from low to high.The spatial shift of vegetation coverage levels between 2009—2016 mainly occurred in the northern and central regions.There is a tendency that the medium-to-low vegetation coverage shifts to medium vegetation coverage,and medium vegetation coverage shifts to medium-to-high vegetation coverage.The annual change rate of vegetation coverage in the study area from 2009 to 2016 was relatively small,displaying an overall trend of gradual increase,while the central and southern parts had a decreasing trend but the trend was insignificant.The correlation coefficient and partial correlation coefficient between the annual vegetation coverage level and annual precipitation and annual average temperature in the study area are small and insignificant.The vegetation coverage of different regions have different responses to climatic factors,and positive and negative correlation coexist in space.The northern part of the study area is greatly influenced by the annual precipitation,while the central part is affected by the average annual temperature.The response of vegetation coverage to climatic factors in the study area was lagging.The growth of vegetation in the growing season was greatly affected by the same month's precipitation and the average temperature in the previous month,and most of the regions presented positive correlation.