PALADYN v1.0, a comprehensive land surface–vegetation–carbon cycle model of intermediate complexity
PALADYN v1.0, a comprehensive land surface–vegetation–carbon cycle model of intermediate complexity
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DOI：
10.5194/gmd-9-3817-2016
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发表时间：
2016-04
影响因子：
5.1
通讯作者：
M. Willeit;A. Ganopolski
中科院分区：
文献类型：
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作者：
M. Willeit;A. Ganopolski
摘要。PALADYN呈现；它是一种新的综合的、计算效率高的陆地表面-植被-碳循环模型，旨在用于长期模拟和古气候研究的中等复杂地球系统模型。该模式以一致的方式处理大气、陆地植被和土壤之间通过能量、水和碳通量的相互作用。能源、水和碳被保存下来。PALADYN明确地将永久冻土视为物理过程和重要的碳库。它区分了九种表面类型：五种不同的植被类型、裸露的土壤、陆地冰、湖泊和海洋大陆架。包括海洋大陆架可以处理与冰期旋回有关的海平面和大陆架面积的连续变化。在每一种地表类型上，该模式求解地表能量平衡，计算感热、潜热和地热以及向上的短波和长波辐射通量。该模型包括一个单一的雪层。植被和裸露的土壤共用一个土壤柱。土壤被垂直地离散成五层，在那里温度、水和碳的预测方程被一致地解决了。明确考虑了土壤中水分的相变。地表水文模块计算植被、地表径流和土壤入渗对降水的截留。土壤水分方程基于达西定律。给定土壤含水量，根据地形指数计算湿地比例。还计算了冰盖上部和海陆架土壤的温度剖面。光合作用是用光利用效率模型计算的。植被的碳同化作用与水分通过气孔导度的蒸腾作用相耦合。PALADYN包括一个动态植被模块，其中包含五种植物功能类型，它们以各自的净初级生产力竞争网格单元份额。PALADYN区分矿物土壤碳，泥炭碳，埋藏碳和陆架碳。每种土壤碳类型都有自己的土壤碳库，一般以凋落物、快碳库和慢碳库为代表。碳可以通过垂直扩散和平流在各层之间重新分布。对于植被宏观地表类型，分解是土壤温度和土壤湿度的函数。永久冻结层中的碳被赋予了很长的周转时间，这有效地将碳锁在永久冻土中。埋在冰原下和被淹没的大陆架上的碳被不同地对待。该模型还包括一个动态泥炭模块。PALADYN包括碳同位素13C和14C，它们通过所有碳库进行跟踪。同位素区分只在光合作用过程中进行模拟。实现了一个简单的甲烷模块来表示湿地（包括泥炭地）和淹水大陆架厌氧碳分解产生的甲烷排放。在模型描述的同时，对当前和历史时期的模型进行了全面的离线模式评估。
Abstract. PALADYN is presented; it is a new comprehensive and computationally efficient land surface–vegetation–carbon cycle model designed to be used in Earth system models of intermediate complexity for long-term simulations and paleoclimate studies. The model treats in a consistent manner the interaction between atmosphere, terrestrial vegetation and soil through the fluxes of energy, water and carbon. Energy, water and carbon are conserved. PALADYN explicitly treats permafrost, both in physical processes and as an important carbon pool. It distinguishes nine surface types: five different vegetation types, bare soil, land ice, lake and ocean shelf. Including the ocean shelf allows the treatment of continuous changes in sea level and shelf area associated with glacial cycles. Over each surface type, the model solves the surface energy balance and computes the fluxes of sensible, latent and ground heat and upward shortwave and longwave radiation. The model includes a single snow layer. Vegetation and bare soil share a single soil column. The soil is vertically discretized into five layers where prognostic equations for temperature, water and carbon are consistently solved. Phase changes of water in the soil are explicitly considered. A surface hydrology module computes precipitation interception by vegetation, surface runoff and soil infiltration. The soil water equation is based on Darcy's law. Given soil water content, the wetland fraction is computed based on a topographic index. The temperature profile is also computed in the upper part of ice sheets and in the ocean shelf soil. Photosynthesis is computed using a light use efficiency model. Carbon assimilation by vegetation is coupled to the transpiration of water through stomatal conductance. PALADYN includes a dynamic vegetation module with five plant functional types competing for the grid cell share with their respective net primary productivity. PALADYN distinguishes between mineral soil carbon, peat carbon, buried carbon and shelf carbon. Each soil carbon type has its own soil carbon pools generally represented by a litter, a fast and a slow carbon pool in each soil layer. Carbon can be redistributed between the layers by vertical diffusion and advection. For the vegetated macro surface type, decomposition is a function of soil temperature and soil moisture. Carbon in permanently frozen layers is assigned a long turnover time which effectively locks carbon in permafrost. Carbon buried below ice sheets and on flooded ocean shelves is treated differently. The model also includes a dynamic peat module. PALADYN includes carbon isotopes 13C and 14C, which are tracked through all carbon pools. Isotopic discrimination is modelled only during photosynthesis. A simple methane module is implemented to represent methane emissions from anaerobic carbon decomposition in wetlands (including peatlands) and flooded ocean shelf. The model description is accompanied by a thorough model evaluation in offline mode for the present day and the historical period.