Models estimating carbon budget at land surface are mainly interested in vertical flux of carbon. On the
other hand, studies on horizontal flux are obviously lacked to confirm that relationship between the hydrological flux
of organic carbon discharged from catchment and terrestrial carbon production, a relation between Total Organic
Carbon(TOC) and Gross Primary Production(GPP) tried analysis through cross correlation. The best correlation
structure is correlation between GPP and TOC of flow-weighted mean concentration from watershed without delay.
Furthermore, cross correlation analysis was performed by consider periodicity. The correlation between TOC and
GPP in summer was similar to correlation without periodicity. Therefore, correlation between GPP and TOC was
most regulated by the correlation between GPP and TOC at summer. As a result, the vegetation carbon and organic
carbon from watershed is recognized a close relationship on the seasonal. Therefore, future research is correlation
analyzing between vegetation variables according season, GPP and TOC, we are expected to use quantitative
understanding that horizontal flux flow of carbon from the surface.