Improved representation of plant functional types and physiology in the Joint UK Land Environment Simulator (JULES v4.2) using plant trait information
Improved representation of plant functional types and physiology in the Joint UK Land Environment Simulator (JULES v4.2) using plant trait information
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DOI：
10.5194/gmd-9-2415-2016
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发表时间：
2016-01-01
影响因子：
5.1
通讯作者：
van Bodegom, Peter
中科院分区：
文献类型：
--
作者：
Harper, Anna B.;Cox, Peter M.;van Bodegom, Peter
动态全球植被模型用于预测植被对气候变化的响应。它们对于规划生态系统管理、理解碳循环-气候反馈以及评估气候变化对全球生态系统的潜在影响至关重要。JULES（联合王国陆地环境模拟器）代表了英国哈德利中心系列模型和第一代英国地球系统模型中的陆地过程。以前，JULES代表五种植物功能类型（PFT）：阔叶树，针叶树，C-3和C-4草和灌木。本研究涉及三个发展朱尔斯。首先，树木和灌木被分为落叶和万年青PFT，以更好地代表自然界中存在的叶寿命和代谢能力的范围。其次，我们区分温带和热带万年青树。这前两个变化导致了一组新的9个PFT：热带和温带阔叶万年青树，阔叶落叶树，针叶万年青和落叶树，C-3和C-4草，万年青和落叶灌木。第三，利用TRY数据库中的数据，我们更新了叶片氮与Rubisco最大羧化速率之间的关系（V-cmax /），并更新了叶周转率和生长速率，以包括叶寿命和每单位面积叶质量之间的权衡。与FLUXNET站点、基于FLUXNET的全球GPP数据集和MODIS NPP相比，与标准的五种PFT相比，新的九种PFT模拟了更高的GPP和NPP，除了寒冷环境中的C-3草和以前生产力过剩的C-4草。在生物群系尺度上，评估的所有8个生物群系的全球初级生产力都得到了提高，大多数生物群系的净初级生产力都得到了提高，但热带森林、稀树草原和热带外混交林除外，因为模拟的净初级生产力太高。采用新的PFT，全球目前的GPP和NPP分别为128和62 Pg C年（-1）。我们的结论是，包括基于性状的数据和万年青/落叶的区别，大大提高了生产力通量在JULES，特别是代表性的GPP。这些发展提高了JULES的真实性，使植被动态和碳储存模拟的置信度更高。
Dynamic global vegetation models are used to predict the response of vegetation to climate change. They are essential for planning ecosystem management, understanding carbon cycle-climate feedbacks, and evaluating the potential impacts of climate change on global ecosystems. JULES ( the Joint UK Land Environment Simulator) represents terrestrial processes in the UK Hadley Centre family of models and in the first generation UK Earth System Model. Previously, JULES represented five plant functional types ( PFTs): broadleaf trees, needle-leaf trees, C-3 and C-4 grasses, and shrubs. This study addresses three developments in JULES. First, trees and shrubs were split into deciduous and evergreen PFTs to better represent the range of leaf life spans and metabolic capacities that exists in nature. Second, we distinguished between temperate and tropical broadleaf evergreen trees. These first two changes result in a new set of nine PFTs: tropical and temperate broadleaf evergreen trees, broadleaf deciduous trees, needle-leaf evergreen and deciduous trees, C-3 and C-4 grasses, and evergreen and deciduous shrubs. Third, using data from the TRY database, we updated the relationship between leaf nitrogen and the maximum rate of carboxylation of Rubisco ( V-cmax /, and updated the leaf turnover and growth rates to include a trade-off between leaf life span and leaf mass per unit area.Overall, the simulation of gross and net primary productivity ( GPP and NPP, respectively) is improved with the nine PFTs when compared to FLUXNET sites, a global GPP data set based on FLUXNET, and MODIS NPP. Compared to the standard five PFTs, the new nine PFTs simulate a higher GPP and NPP, with the exception of C-3 grasses in cold environments and C-4 grasses that were previously over-productive. On a biome scale, GPP is improved for all eight biomes evaluated and NPP is improved for most biomes - the exceptions being the tropical forests, savannahs, and extratropical mixed forests where simulated NPP is too high. With the new PFTs, the global present-day GPP and NPP are 128 and 62 Pg C year(-1), respectively. We conclude that the inclusion of trait-based data and the evergreen/deciduous distinction has substantially improved productivity fluxes in JULES, in particular the representation of GPP. These developments increase the realism of JULES, enabling higher confidence in simulations of vegetation dynamics and carbon storage.