Modeling gross primary production in semi-arid Inner Mongolia using MODIS imagery and eddy covariance data

Ranjeet John, University of Toledo, ranjeet.john@utoledo.edu (Presenter)
Jiquan Chen, The University of Toledo, jiquan.chen@utoledo.edu
Asko Noormets, North Carolina State University, anoorme@ncsu.edu
Xiangming Xiao, University of Oklahoma, xiangming.xiao@ou.edu
Jianye Xu, The University of Toledo, jianye.xu@utoledo.edu
Shiping Chen, Insitute of Botany, Chinese Academy of Sciences, spchen@ibcas.ac.cn

Semi-arid Inner Mongolia is experiencing climate change with associated land cover/use change that includes an increase in irrigated agriculture and population growth. We evaluate temporal scaling up of carbon fluxes from eddy covariance (EC) tower observations in different water-limited land cover/use and biome types. The Vegetation Photosynthesis model (VPM) and modified VPM (MVPM), driven by Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI) for 2006-2007 that were derived from MODIS surface reflectance product (MOD09A1) was used to scale up and validate temporal changes in GPP from the EC towers during 2006 & 2007 growing seasons. The VPM model predicted the annual GPP (GPP_VPM) reasonably well at the Duolun cropland (R² = 0.67 & 0.71) and Xilinhaote typical steppe (R² = 0.80 & 0.73). The predictive power of VPM varied in the desert steppe, at an irrigated poplar stand (R² = 0.74 & 0.68) and nearby shrubland in Kubuqi (R² = 0.31 & 0.49). The comparison between GPP_tower and GPP_MVPM predicted GPP showed good agreement for the Xilinhaote typical steppe (R² = 0.84 & 0.70) in 2006-2007, Duolun typical steppe (R² = 0.63), and cropland (R² = 0.63) in 2007. The predictive power of MVPM decreased slightly in the desert steppe, at the irrigated poplar stand (R² = 0.55 & .47) and the shrubland (R² = 0.20 & 0.41). The results of this study demonstrate the feasibility of scaling up GPP from EC towers to the regional scale.

Presentation Type:  Poster

Session:  Coupled Processes at Land-Atmosphere-Ocean Interfaces   (Mon 4:00 PM)

Associated Project(s): 

• Chen, Jiquan: Interactive Changes of Ecosystems and Societies on the Mongolian Plateau: From Coupled Regulations of Land Use and Changing Climate to Adaptation ...details

Poster Location ID: 40