Technical Note: The Simple Diagnostic Photosynthesis and Respiration Model (SDPRM)

[摘要] We present a Simple Diagnostic Photosynthesis and Respiration Model (SDPRM)that has been developed based on pre-existing formulations. Thephotosynthesis model is based on the light use efficiency logic forcalculating the gross primary production (GPP), while the ecosystemrespiration (R_eco) is a modified version of an Arrhenius-type equation.SDPRM is driven by satellite-derived fAPAR (fraction of AbsorbedPhotosynthetically Active Radiation) and climate data from the National Center for EnvironmentalPrediction/National Center for Atmospheric Research Reanalysis (NCEP/NCAR). Themodel estimates 3-hourly values of GPP for seven major biomes and dailyR_eco. The motivation is to provide a priori fields of surface CO₂fluxes with fine temporal and spatial scales for atmospheric CO₂inversions. The estimated fluxes from SDPRM showed that the model is capableof producing flux estimates consistent with the ones inferred fromatmospheric CO₂ inversion or simulated from process-based models. In thisTechnical Note, different analyses were carried out to test the sensitivityof the estimated fluxes of GPP and CO₂ to their driving forces. Thespatial patterns of the climatic controls (temperature, precipitation, water)on the interannual variability of GPP are consistent with previous studies,even though SDPRM has a very simple structure and few adjustable parametersand hence it is much easier to modify in an inversion than more sophisticatedprocess-based models. In SDPRM, temperature is a limiting factor for theinterannual variability of R_eco over cold boreal forest, whileprecipitation is the main limiting factor of R_eco over the tropics and thesouthern hemisphere, consistent with previous regional studies.

[学科分类] 地球化学与岩石