Research into carbon sequestration service has increased in an effort to explore policy regimes for tackling climate change risks. However, questions concerning the carbon sequestration service transmission over the spatial units are too often unexploited while mainstreaming it into policy-making. On the basis of the CA model and laws of thermodynamics, the research depicted the spatial flow of carbon sequestration service via a grid matching method with a focus on the trans-boundary watershed of China, Russia, and DPRK. We simulated flow directions (N = 9) and potential fluxes (0 < F < 87.68 g) of carbon sequestration service flow in the watershed, and analyzed the spatial distribution of it. Our results illustrated that 15.28% of the trans-boundary watershed was recognized as non-flow regions, which possessed 136.71 Tg of total carbon sequestration. We highlighted how, depending on the spatial flow being simulated, the non-flow regions limit the service transmission, thereby influencing the local value of actual carbon sequestration service supply.

Keywords: ecosystem service flow, carbon sequestration service, grid matching, trans-boundary watershed