## 4 Discussion
Although CO\({}_{2}\) emissions attributable to agricultural biomass waste burning were counted in the anthropogenic emission data [129; 130] that we used, photosynthetic CO\({}_{2}\) uptake and crop-soil CO\({}_{2}\) emissions in agricultural systems distributed in our study area were not included and could potentially be calculable based on a model described by [PERSON] et al. [157]. According to our hourly integrated biogenic CO\({}_{2}\) emission, photosynthetic CO\({}_{2}\) uptake and net biogenic CO\({}_{2}\) flux results discussed in Section 3.6, the range of integrated hourly biogenic to anthropogenic CO\({}_{2}\) emissions ratio in winter (2.27 \(\pm\) 0.11%-4.97 \(\pm\) 1.17%) was similar to the value (4-5%) estimated in earlier urban CO\({}_{2}\) flux studies [24; 42; 158]. However, the modeled ratio range in summer (13.71 \(\pm\) 2.44%-23.62 \(\pm\) 3.13%) was much higher than reference values, probably because our study area included much more vegetated land than Los Angeles [24], or a higher vegetation fraction than the neighborhood-scale studies in Singapore and Mexico City [42; 158]. In terms of CO\({}_{2}\) removal, the range of integrated hourly photosynthetic uptake to anthropogenic CO\({}_{2}\) emission ratio in winter (up to 19.07 \(\pm\) 5.33%) was comparable to the series of 1.4% in [PERSON] et al. [158], 8% in [PERSON] et al. [42], 10% in [PERSON] et al. [24], 14% in [PERSON] et al. [49], and 20-24% in [PERSON] et al. [159]. In summer, the ratio of photosynthetic uptake to anthropogenic emissions (79.04 \(\pm\) 12.31%) was higher than the estimate (69%) for a July afternoon in Boston [29]. The summer daytime integrated hourly net biogenic to anthropogenic CO\({}_{2}\) flux ratio (up to 55.42 \(\pm\) 10.39%) was higher than the 20% offset by daytime \(NEE\) in Paris [33] and up to 31% estimated by [PERSON] et al. [41] while our winter daytime estimates was only up to 14.15 \(\pm\) 4.24%. Forests, grasslands, and urban greenspaces in the Greater Tokyo Area showed potential to offset Tokyo's anthropogenic CO\({}_{2}\) emissions, especially during the growing season. According to Table 3, our model estimated 5.14 \(\pm\) 0.47 \(\times\) 10\({}^{6}\) tonCO\({}_{2}\) year\({}^{-1}\) of photosynthetic uptake and 1.98 \(\pm\) 0.19 \(\times\) 10\({}^{6}\) tonCO\({}_{2}\) year\({}^{-1}\) of biogenic emission in the partially vegetated urban land (1374.62 \(\pm\) 134.05 km\({}^{2}\)) in the Greater Tokyo Area. Another 1665.31 km\({}^{2}\) of urban land in the study area was also identified as having partial vegetation cover by the MODIS vegetation continuous fields product (MOD4B), but was without valid \(LAI\) data to proceed any simulation. Additionally, if the rest of the urban land (about 7065.07 km\({}^{2}\)) in our study area was fully covered by DBF, EBF, ENF or GRS instead, 3.25 \(\pm\) 0.18 \(\times\) 10\({}^{7}\), 3.84 \(\pm\) 0.06 \(\times\) 10\({}^{7}\), 4.75 \(\pm\) 0.10 \(\times\) 10\({}^{7}\) or 3.64 \(\pm\) 0.49 \(\times\) 10\({}^{7}\) ton year\({}^{-1}\) more CO\({}_{2}\) would be captured by photosynthesis, while 1.73 \(\pm\) 0.19 \(\times\) 10\({}^{7}\), 2.08 \(\pm\) 0.21 \(\times\) 10\({}^{7}\), 2.68 \(\pm\) 0.27 \(\times\) 10\({}^{7}\) or 3.37 \(\pm\) 0.71 \(\times\) 10\({}^{7}\) ton year\({}^{-1}\) more CO\({}_{2}\) would be emitted via biogenic respiration and SOC decomposition. Nonetheless, one must bear in mind that once the spatial range of hourly integrated calculation changed, so would the results [49; 160]. These values were the total of \(GPP\), \(R_{e}\), and \(NEE\) in ecosystems of different types under various environmental conditions. It is too complicated to make an interpretation without discussing factors such as near-ground CO\({}_{2}\) storage [161; 162; 163], which affect the actual biogenic offset of anthropogenic CO\({}_{2}\) emissions. For that reason, the gridded estimates of sub-daily biogenic CO\({}_{2}\) flux are supplied to the transport model AIST-MM for inversion analysis of anthropogenic CO\({}_{2}\) emissions in cities such as Tokyo.