Abstract
Abstract. We describe an implementation of the Ecosystem Demography (ED) concept in the Community Land Model. The structure of CLM(ED) and the physiological and structural modifications applied to the CLM are presented. A major motivation of this development is to allow the prediction of biome boundaries directly from plant physiological traits via their competitive interactions. Here we investigate the performance of the model for an example biome boundary in eastern North America. We explore the sensitivity of the predicted biome boundaries and ecosystem properties to the variation of leaf properties using the parameter space defined by the GLOPNET global leaf trait database. Furthermore, we investigate the impact of four sequential alterations to the structural assumptions in the model governing the relative carbon economy of deciduous and evergreen plants. The default assumption is that the costs and benefits of deciduous vs. evergreen leaf strategies, in terms of carbon assimilation and expenditure, can reproduce the geographical structure of biome boundaries and ecosystem functioning. We find some support for this assumption, but only under particular combinations of model traits and structural assumptions. Many questions remain regarding the preferred methods for deployment of plant trait information in land surface models. In some cases, plant traits might best be closely linked to each other, but we also find support for direct linkages to environmental conditions. We advocate intensified study of the costs and benefits of plant life history strategies in different environments and the increased use of parametric and structural ensembles in the development and analysis of complex vegetation models.
Highlights
The storage of carbon on the land surface, and how the land surface interacts with the atmosphere, are both determined to some extent by the distribution of plant types, or ecosystem composition, across the globe
Particular features of this model structure include (1) the flexible representation of plant functional type parameterization, (2) the representation of plant demography and succession derived from the Ecosystem Demography (ED) concept, (3) the representation of self-organization of plants into distinct canopy layers derived from the PPA model, (4) the solution of canopy processes at relatively high temporal and vertical resolutions, and (5) the ability to represent multiple different plant types within the same vertical light profile
We introduce a new methodology for the simulation of vegetation dynamics into the Community Land Model (v4.5)
Summary
The storage of carbon on the land surface, and how the land surface interacts with the atmosphere, are both determined to some extent by the distribution of plant types, or ecosystem composition, across the globe. Given projected changes in climate, the composition of ecosystems may well be expected to change in the coming decades and centuries (Cox et al, 2000; Sitch et al, 2003), and the carbon stored on the land is potentially subject to large deviations from the current state. Biome shifts such as woody encroachment in the Arctic with a warmer climate (Levis et al, 2000; Swann et al, 2010) and greening of the Sahara with a wetter climate (Levis et al, 2004) significantly alter climate by changing surface albedo and evapotranspiration (Rogers et al, 2013). The representation of biome distribution has emerged as a key new feature of Earth system models (ESMs) in recent years (Cox et al, 2000; Levis et al, 2004; Krinner et al, 2005; Sato et al, 2007).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
