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草业学报 ›› 2013, Vol. 22 ›› Issue (5): 1-10.DOI: 10.11686/cyxb20130501

• 研究论文 •    下一篇

2002-2010年青藏高原植被含水量微波遥感动态监测

陈思宇,于惠,冯琦胜,梁天刚*   

  1. 草地农业生态系统国家重点实验室 兰州大学草地农业科技学院,甘肃 兰州 730020
  • 出版日期:2013-10-20 发布日期:2013-10-20
  • 通讯作者: E-mail:tgliang@lzu.edu.cn
  • 作者简介:陈思宇(1987-),女,甘肃定西人,在读硕士。
  • 基金资助:
    国家自然科学基金项目(30972135,41071342),教育部高等学校科技创新工程重大项目培育资金项目(708089)和国家科技支撑计划项目(2009BAC53B01)资助。

Dynamic monitoring of vegetation water content based on microwave remote sensing in the Qinghai-Tibetan Plateau region from 2002 to 2010

CHEN Si-yu, YU Hui, FENG Qi-sheng, LIANG Tian-gang   

  1. State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science
    and Technology, Lanzhou University, Lanzhou 730020, China
  • Online:2013-10-20 Published:2013-10-20

摘要: 水分是衡量植被生理状态和形态结构的重要参数。青藏高原在区域生态环境和全球气候变化等方面扮演重要角色,但对其在植被含水量时空变化动态及其与气候的关系方面缺乏系统研究。基于236个地面样方实测数据和AMSR-E每日亮温数据,利用留一法交叉验证方法确立了青藏高原植被含水量的遥感反演模型。同时,估算了青藏高原植被含水量空间分布,分析了2002-2010年植被含水量的时间动态及其与气候变化的关系,结果表明,1)微波极化指数(MPI)优于微波植被指数(MVI),18 GHz的MPI乘幂模型AWC=128.93×MPI-0.67可以很好地反映植被绝对含水量(AWC)空间变化动态;2)青藏高原7月份日植被含水量由西北向东南呈带状递增的趋势。其中,西北部至中部的大部分地区植被含水量主要集中在800 kg/hm2以下,东南部植被含水量较西北地区明显增加,主要集中在800~4 000 kg/hm2之间;3)多年平均月际间的植被含水量存在明显的空间异质性,其变差系数具有由西向东逐渐增加的趋势;4)温度和降水与植被含水量之间具有一定的相关关系,其中降水对植被含水量的影响存在明显的滞后性。

Abstract: Water is an important parameter governing vegetation physiological status and formation structure. The Qinghai-Tibetan Plateau plays an important role in the regional ecological environment and global climate changes, but there is a lack of research on spatial temporal variation of vegetation water content and the relationship between water content and climatic factors. Using the “Leave One Out Cross Validation” (LOOCV) method, an inversion model of vegetation water content was established in the Qinghai-Tibetan Plateau region based on 236 observed data with corresponding AMSR-E daily brightness temperature data. By simulating the distribution of water content in the Qinghai-Tibetan Plateau, the dynamic variations of vegetation water content and the relationship between water content and climatic factor were analyzed from 2001 to 2010. The Microwave Polarization Index (MPI) is superior to the microwave vegetation index in this region, and the power model based on 18 GHz MPI AWC=128.93×MPI-0.67 has the highest accuracy, and better reflects the condition of the Absolute Vegetation Water Content (AWC). Daily vegetation water content of the Qinghai-Tibetan Plateau in July shows a belt with an increasing trend from northwest to southeast, in which the vegetation water content is mainly below 800 kg/ha in the western and central regions. Compared with the northwest, the southeast vegetation water content has an increased trend, mainly between 800 and 4 000 kg/ha. The inter-monthly variability of vegetation water content has obvious spatial differences in recent years which increases from west to east on the Qinghai-Tibetan plateau. Some relationships between temperature, precipitation and the vegetation water content, show a hysteresis response to rainfall.

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