Estimating gross primary productivity by using satellite - derived daily Boreal Ecosystem Productivity Simulator over Europe region

Theme 3. Meteorological Cooperation
Session Name 3.1 Opportunities and challenges of remote sensing techniques to meet current and future needs for monitoring the Arctic
Datetime Sep 07, 2018 01:55 PM - 02:10 PM (UTC +3)
Location Room 15
Presentation Type Oral
Presenter Jiahua Zhang
Author(s) Jiahua Zhang (Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences, China), Fengmei Yao (College of Earth and Planetary Sciences, University of Chinese Academy of Sciences (UCAS), China), Sha Zhang (Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences, China), Huadong Guo (Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences, China)
Abstract text

Vegetation gross primary productivity (GPP) is an important component in the global carbon cycle, In recently , the remote sensing technique has been widely used to detect GPP. Previous studies show that ecosystem models usually overestimate GPP under drought and during spring, late fall and winter. In this study, these issues are addressed in the satellite-derived daily boreal ecosystem productivity simulator (BEPSd) by introducing a new water stress factor (fw) to replace the old one and a designed fraction in term of remote sensing -normalized difference vegetation index (NDVI) (fndvi) to indicate the effect of chlorophyll on photosynthesis. GPP simulations are conducted at 41 flux sites across Europe (3 sites are located in Arctic region) to test BEPSd with the new fw and fndvi.  The new fw captures drought conditions well and fndvi expresses the chlorophyll constraint on photosynthesis. And, the BEPSd incorporating both the new fw and fndvi gives better simulations than the old version, particularly for evergreen broadleaf forest, deciduous broadleaf forest and closed shrub with R (RMSE) value increasing (decreasing) from 0.69 to 0.74 , 0.72 to 0.82 , 0.54 to 0.75 , respectively. Furthermore, the new fw effectively mitigates GPP overestimates under drought, and fndvi counteracts GPP overestimates during spring, late fall and winter. Overall, the improved BEPSd indicates a satisfactory performance at flux sites over Europe, and shows a potential to detect vegetation GPP in the Arctic region.

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