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Showing posts from July, 2018

From watershed to global

Ever since I finished my 3D ecosystem simulation using the ECO3D model, I started to think about applying this model to a larger spatial domain such as global.

While there are several technical difficulties in doing so, there are also different combinations of solutions to resolve these issues. In this post I will list out major issues we will address:

First, on a global scale, we need much more massive input data preparation. What's more, some traditional algorithm/method may not even work. For example, the watershed lineation process on global scale will not be used anymore. Instead, another river routing algorithm or dataset should be used.File I/O will becomes an issue. Global scale simulation will use parallel computing, which mean the file I/O must support parallel reading/writing. Whether file system will be ideal or other options remains unclear. For example, can we use database or Hadoop?Parallel computing with/without MPI/OpenMP. I am not sure of other options but running…

Some review on the fate of dissolved organic carbon in terrestrial ecosystem

My recent modeling work involves some rewind of the process happened near the land surface, which causes some issue to the estimate of dissolved organic carbon (DOC) dynamics in terrestrial ecosystem.

I will skip the importance of DOC because you can find plenty of literatures online but instead I will focus on the challenge from a modeler's perspective.

First, we need to understand the source of DOC. Generally we think DOC is produced due to decomposition process and water flux. As we know, microbial decomposition occurs within nearly all places within the ecosystem: litter, soil and aquatic systems, etc. But water may not be present all the times in some ecosystem components.

In litter, decomposition is a continuous process through which fresh vegetation is transferred into organic carbon and enter into soil. However, a portion of the organic carbon may be transported through water flux in form of DOC during snowmelt, runoff and surface leaching. In this case, it is almost certa…