Modeling sensitivity of biogenic VOC emissions to environmental factors

Abstract : Global inventory of biogenic VOC emissions MEGAN-MACC (REF) has been created using the model MEGANv2.1 (Guenther et al., 2012). Emissions of the main chemical species emitted by vegetation were estimated on monthly basis for the period of 1980 – 2010. The global BVOC emission total is dominated by isoprene (69% of global total). Further, we present three sensitivity isoprene emission inventories. Dataset SM accounts for impact of soil moisture deficiency on isoprene emission. In dataset titled SW a simplified calculation of PAR (Photosynthetically Active Radiation) input variable has been used assuming that PAR equals to ½ of incoming shortwave radiation. In dataset CRU, we replaced the MERRA meteorological fields (used for the reference as well as for SM and SW datasets) by the meteorological inputs from the CRU-NCEP reanalysis. These variations in driving environmental factors resulted in substantial changes of isoprene global total which decreased by 50% in SM, increased by 16% in SW and decreased by 27% in CRU sensitivity model runs when compared to the reference.