植物生态学报 ›› 2017, Vol. 41 ›› Issue (3): 337-347.DOI: 10.17521/cjpe.2016.0182

所属专题: 遥感生态学

• 研究论文 • 上一篇    下一篇

遥感GPP模型在中国地区多站点的应用与比较

王克清, 王鹤松*(), 孙建新   

  1. 北京林业大学林学院, 北京 100083
  • 出版日期:2017-03-10 发布日期:2017-04-12
  • 通讯作者: 王鹤松
  • 作者简介:* 通信作者Author for correspondence (E-mail:sunzhiqiang1956@sina.com)
  • 基金资助:
    国家林业公益性行业科研专项(201404201)和中央高校基本科研业务费专项(BLX2015-16)

Application and comparison of remote sensing GPP models with multi-site data in China

Ke-Qing WANG, He-Song WANG*(), Osbert Jianxin SUN   

  1. College of Forestry, Beijing Forestry University, Beijing 100083, China
  • Online:2017-03-10 Published:2017-04-12
  • Contact: He-Song WANG
  • About author:KANG Jing-yao(1991-), E-mail: kangjingyao_nj@163.com

摘要:

在区域和全球尺度上估算植被总初级生产力(GPP)对理解陆地生态系统的碳循环具有重要意义。由于地表异质性的存在, 局限在站点尺度上的观测数据无法直接扩展到更大空间尺度的区域上。通过与地面观测数据相结合, 遥感成为实现植被GPP空间扩展的主要工具。但是现有模型对气象数据依赖较多, 且在不同气象数据集的驱动下, 模拟结果间会有差异, 进而产生不确定性。建立以遥感数据为主的GPP模型(简称遥感GPP模型), 使其易于在区域和全球尺度上应用, 是解决上述问题的一个可行方案。该研究使用TG (temperature and greenness model)和VI (vegetation index model)两个遥感GPP模型, 结合中国通量观测研究联盟(ChinaFLUX)的台站数据, 对中国典型植被类型的GPP进行了模拟、比较与评估, 旨在进一步提高遥感GPP模型在中国区域的适用性。结果表明: (1) TG和VI模型选用的遥感参数均与GPP观测值有较高的相关性, 都可以得到可信的光合转换系数ma。基于与夜间地表温度平均值的相关关系, ma在空间尺度上得到了扩展, 这使得TG和VI都可以应用到区域尺度上。(2) TG和VI模型的模拟值与实测值间的相关性大多较高, 决定系数(R2)多在0.67以上。但不同台站间的误差变动较大, TG模型的均方根误差为0.29-6.40 g·m-2·d-1, VI模型的均方根误差为0.31-7.09 g·m-2·d-1。(3)总体而言, TG模型的表现优于VI, 尤其在海拔或纬度较高、以温度限制为主的台站, TG模型的模拟效果较好。上述结果初步揭示遥感GPP模型具备了在区域尺度上应用的潜力。

关键词: 总初级生产力, 遥感, 增强植被指数, 地表温度, 涡度协相关

Abstract:

Aims Estimation of gross primary productivity (GPP) of vegetation at the global and regional scales is important for understanding the carbon cycle of terrestrial ecosystems. Due to the heterogeneous nature of land surface, measurements at the site level cannot be directly up-scaled to the regional scale. Remote sensing has been widely used as a tool for up-saling GPP by integrating the land surface observations with spatial vegetation patterns. Although there have been many models based on light use efficiency and remote sensing data for simulating terrestrial ecosystem GPP, those models depend much on meteorological data; use of different sources of meteorological datasets often results in divergent outputs, leading to uncertainties in the simulation results. In this study, we examines the feasibility of using two GPP models driven by remote sensing data for estimating regional GPP across different vegetation types. Methods Two GPP models were tested in this study, including the Temperature and Greenness Model (TG) and the Vegetation Index Model (VI), based on remote sensing data and flux data from the China flux network (ChinaFLUX) for different vegatation types for the period 2003-2005. The study sites consist of eight ecological stations located in Xilingol (grassland), Changbaishan (mixed broadleaf-conifer forest), Haibei (shrubland), Yucheng (cropland), Damxung (alpine meadow), Qianyanzhou (evergreen needle-leaved forest), Dinghushan (evergreen broad-leaved forest), and Xishuangbanna (evergreen broad-leaved forest), respectively. Important findings All the remote sensing parameters employed by the TG and VI models had good relationships with the observed GPP, with the values of coefficient of determination, R2, exceeding 0.67 for majority of the study sites. However, the root mean square errors (RMSEs) varied greatly among the study sites: the RMSE of TG ranged from 0.29 to 6.40 g·m-2·d-1, and that of VI ranged from 0.31 to 7.09 g·m-2·d-1, respectively. The photosynthetic conversion coefficients m and a can be up-scaled to a regional scale based on their relationships with the annual average nighttime land surface temperature (LST), with 79% variations in m and 58% of variations in a being explainable in the up-scaling. The correlations between the simulated outputs of both TG and VI and the measured values were mostly high, with the values of correlation coefficient, r, ranging from 0.06 in the TG model and 0.13 in the VI model at the Xishuangbanna site, to 0.94 in the TG model and 0.89 in the VI model at the Haibei site. In general, the TG model performed better than the VI model, especially at sites with high elevation and that are mainly limited by temperature. Both models had potential to be applied at a regional scale in China.

Key words: gross primary productivity, remote sensing, enhanced vegetation index, land surface temperature, eddy covariance