地理学报 ›› 2014, Vol. 69 ›› Issue (1): 15-30.doi: 10.11821/dlxb201401002

• 土地利用与土地覆盖 • 上一篇    下一篇

1982-2010年中国草地覆盖度的时空动态及其对气候变化的响应

周伟1, 刚成诚1, 李建龙1, 章超斌1, 穆少杰1, 孙政国2   

  1. 1. 南京大学生命科学学院, 南京210093;
    2. 南京农业大学动物科技学院, 南京210095
  • 收稿日期:2013-09-10 修回日期:2013-10-20 出版日期:2014-01-20 发布日期:2014-01-20
  • 作者简介:周伟(1985-),女,山东泰安人,在读博士,主要从事遥感技术应用和全球变化陆地生态系统碳循环方面的研究。E-mail:zhouw866@163.com
  • 基金资助:
    国家重点基础研究发展计划(973 计划) 项目(2010CB950702);亚太全球变化研究网络(APN) 项目(ARCP2013-16NMY-Li);国家自然科学基金项目(40871012;J1103512;J1210026);国家863 计划专题项目(2007AA10Z231);澳大利亚国际发展机构(AusAID) 项目(64828)

Spatial-temporal dynamics of grassland coverage and its response to climate change in China during 1982-2010

ZHOU Wei1, GANG Chengcheng1, LI Jianlong1, ZHANG Chaobin1, MU Shaojie1, SUN Zhenguo2   

  1. 1. School of Life Science, Nanjing University, Nanjing 210093, China;
    2. College of Animal Sciences, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2013-09-10 Revised:2013-10-20 Online:2014-01-20 Published:2014-01-20
  • Contact: 李建龙(1962-),教授,E-mail:jlli2008@nju.edu.cn
  • Supported by:
    The National Basic Research Program of China, No.2010CB950702; APN Project ARCP 2013-16NMY-Li; National Natural Science Foundation of China, No.40871012; No.J1103512; No.J1210026; National High Technology Research and Development Program of China, No.2007AA10Z231; The Public Sector Linkages Program supported by Aus AID, No.64828

摘要: 基于1982-2006 年的GIMMS NDVI 数据和2001-2010 年的MODIS NDVI 数据反演中国草地覆盖度的空间格局和变化趋势,结合1982-2010 年中国气象站点气温和降水数据,分别从不同时空尺度和不同草地类型上分析中国草地覆盖度的年际和月际变化对气候变化的响应。结果表明:(1) 1982-2010 年间中国草地分布区气温呈上升趋势(0.04 ℃/年),降水量呈减少趋势(-0.39 mm/年),西北干旱区气候暖湿化趋势明显。(2) 中国草地覆盖度空间上呈现东南高西北低的特征,29 年间草地覆盖度平均值为34%,坡面草地覆盖度最高为61.4%,荒漠草地覆盖度最低为17.1%。(3) 29 年间中国草地覆盖度总体呈现上升趋势,平均为0.17%/年,西北干旱和青藏高原地区草地覆盖度增加趋势明显。坡面草地覆盖度增加趋势最明显,平均值为0.27%/年,平原草地和草甸增加趋势较小,平均值仅为0.11%/年和0.10%/年。总体上,中国草地覆盖度呈极显著增加(46.03%) 和显著增加的面积比例(11%)大于极显著减少(4.1%)和显著减少的面积比例(3.24%)。(4) 从年际变化上,草地覆盖度与气温和降水量均呈不显著正相关(R = 0.21;R = 0.1);从不同草地类型上,荒漠草地和平原草地覆盖度受降水量影响较大,而高山亚高山草甸、高山亚高山草地、坡面草地和草甸覆盖度与温度相关性较大。(5) 从月际变化上,草地覆盖度与当月气温、降水量具有显著的相关性(R = 0.80;R = 0.76),表明水热因子的季节波动对牧草生长的影响更大;并且所有类型植被覆盖度与前一月气温和降水量的相关系数最大,表现出明显的时滞效应。

关键词: 草地覆盖度, 气温, 降水, 时空动态, 相关性, 滞后效应

Abstract: Global climate warming has led to significant vegetation changes in the past half century. Grassland in China, most of which is sensitive to climatic change and ecologically fragile region, undergoes a process of prominent warming and drying. It is necessary to investigate the response of grassland to the climatic variations (temperature and precipitation) for a better understanding of the accumulated consequence of climate change. Vegetation coverage, as an important indicator for evaluating grassland ecosystem condition, is used to monitor grassland change. GIMMS NDVI from 1982 to 2006 and MODIS NDVI from 2001 to 2010 were adopted and integrated in this study to extract the time series of grassland coverage, and to analyze its spatial pattern and changes. The response of grassland coverage to climatic variations at annual and monthly time scales was analyzed using temperature and precipitation time series at Chinese meteorological stations from 1982 to 2010. During the 29 years, the national annual surface air temperature increased with an annual rate of 0.04℃, while national precipitation decreased with an annual rate of -0.39 mm with the exception of Northwest China. Grassland coverage distribution increased from northwest to southeast across China. During 1982-2010, the mean national grassland coverage was 34% but exhibited apparent spatial heterogeneity being highest (61.4%) in slope grasslands and lowest (17.1%) in desert areas. There was a slight increase of the grassland coverage over the study period with an annual rate of 0.17%. Regionally, the largest increase in the grassland area was observed in Northwest China and Tibetan Plateau. The increase in slope grassland areas was as high as 0.27% per year, while in the plain grassland and meadow, the grassland coverage increase was the lowest (being 0.11% per year and 0.1% per year, respectively). Across China, the grass coverage with extremely significant (P<0.01) and significant (P<0.05) area increases accounted for 46.03% and 11% of the total grassland area, respectively, while those with extremely significant and significant decrease were only 4.1% and 3.24% , respectively. At the annual time scale, there were no significant correlations between grassland coverage and annual temperature and precipitation for the total grassland area. However, the grass coverage was mainly affected by temperature in alpine and sub-alpine grassland, alpine and sub-alpine meadow, slope grassland and meadow, while grass coverage in desert grassland and plain grassland was mainly affected by precipitation. At the monthly time-scale, there are significant correlations between grass coverage with both temperature and precipitation, indicating that the grass coverage is mainly affected by seasonal fluctuations of the hydrothermal factors. Additionally, there is obvious time lag-effect between grass growth and climate factors for each grassland type: the highest correlations are observed between the grass coverage and temperature and precipitation of the preceding month.

Key words: grassland coverage, temperature, precipitation, spatial-temporal dynamics, correlation, time lag effect