## 3 Results
### Spatial Distributions of Carbon Fluxes for the Selected Major Land Uses
#### 3.3.1 Spatial Distributions of GPP  
All climate zones showed low GPP in December 2015 and 2018. UC and ET climate zones showed higher GPP during May-September in 2015 and May-August in 2018 than other months. In comparison, the observed monthly GPP from May to September in 2015 was lower than in 2018. For example, UC and ET climate zones showed GPP \(>\) 401 g C m\({}^{-2}\) in August 2018 and \(<\)400 g C m\({}^{-2}\) in August 2015. Forest and pasturelands of ET climate zone showed GPP increased from April to June in 2015, and April to May in 2018, but decreased from May to June in 2018. On the other hand, cropland of UC climate zone had higher GPP than the HP climate zone during the study period, which shows these two locations had a different climate (Figure 7).  
Foresitland of ET and TP climate zones had different GPP distributions during the study period. The observed GPP in ET climate zone was low to high (51-100 g C m\({}^{-2}\) mo\({}^{-1}\) (December to \(>\)400 g C m\({}^{-2}\) mo\({}^{-1}\) (August)), whereas it was low (\(<\)50 g C m\({}^{-2}\) mo\({}^{-1}\) (December)) to average (101-150 g C m\({}^{-2}\) mo\({}^{-1}\) (August)) in the TP climate zone during the study period. On the other hand, GPP decreased from August to September in 2015 and 2018 at both climate zones. The pasture-dominated region of ET and NC climate zones showed an increasing trend from April to June and decreasing trend from August to December. However, ET climate zone had higher GPP than NC climate zone (Figure 7).  
The eastern portions of TP and EP zones were dominated by shrubland. Shrubland in TP climate zone showed low GPP throughout the study period except in August 2018, whereas EP climate zone showed an average GPP, but an increasing trend from April to June in 2015 and an increasing trend from April to May, but a decreasing trend from May to June in 2018. However, EP zone showed a decreasing trend of GPP from August to December. In August 2018, shrubland-dominated areas of TP and EP climate zones showed the average and high GPP, respectively. The developed land of ET climate zone showed higher GPP than the SC climate zone each month during the study period, except in December when both zones showed low GPP (Figure 7).  
During April to June, and December, the area with low GPP (\(<\)50 g C m\({}^{-2}\) mo\({}^{-1}\)) increased by 16 to 26% in 2018 from 2015, whereas during August and September, it decreased by 5 to 8% (Table 2). While there were no consistent changes in spatial coverage observed for the particular GPP ranges in any month, some of the months had higher changes in spatial coverage for low to average (0 to 300 g C m\({}^{-2}\) mo\({}^{-1}\)) GPP range, whereas other months had higher changes in spatial coverage for high GPP range (\(>\)301 g C m\({}^{-2}\) mo\({}^{-1}\)). For example, May and August 2018 had, respectively, 0.04% and 8.49% more area than 2015, having GPP greater than 400 g C m\({}^{-2}\) mo\({}^{-1}\). The changes in spatial coverage analysis showed 16.47% more area in December 2015 had GPP from 51 to 150 g C m\({}^{-2}\) mo\({}^{-1}\) than in December 2018. In addition, 32.45% more area in April 2015 had GPP from 51 to 200 g C m\({}^{-2}\) mo\({}^{-1}\) than in April 2018. In May, 1.04% more area had GPP from 301 to 400 g C m\({}^{-2}\) mo\({}^{-1}\) in 2018 than in 2015 whereas, in September, 0.21% more area had GPP from 301 to 400 g C m\({}^{-2}\) mo\({}^{-1}\) in 2015 than in 2018. However, in June, 0.66% more, and 0.18% less area had GPP from 301 to 400 g C m\({}^{-2}\) mo\({}^{-1}\) in 2018 than in 2015 (Table 2).  
The analysis showed warmer and wetter climate zones, and months had higher GPP than the cooler and dryer zones and months during the study period. Moreover, some croplands and forestland showed higher GPP than shrub and pasturelands.