Vegetation distribution and terrestrial carbon cycle in a carbon cycle configuration of JULES4.6 with new plant functional types
Vegetation distribution and terrestrial carbon cycle in a carbon cycle configuration of JULES4.6 with new plant functional types
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DOI：
10.5194/gmd-11-2857-2018
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发表时间：
2018-07-13
影响因子：
5.1
通讯作者：
Duran-Rojas, Carolina
中科院分区：
文献类型：
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作者：
Harper, Anna B.;Wiltshire, Andrew J.;Duran-Rojas, Carolina
动态全球植被模型（DGVM）用于研究植被和陆地碳循环的历史和未来变化。JULES（联合英国陆地环境模拟器）代表哈德利中心气候模型和英国地球系统模型中的陆地表面。最近，JULES中的植物功能类型（PFT）的数量从5个扩展到9个，以更好地代表全球生态系统的功能多样性。在这里，我们引入了一个更机械化的植被动态表示TRIFID，动态植被组件的JULES，它允许任何数量的PFT竞争完全基于他们的高度，因此，以前的硬连线的优势层次被删除。与前五个PFT版本相比，新的一组9个PFT，JULES能够更准确地再现全球植被分布。这些改善包括热带和北方森林的树木覆盖率以及灌木减少，后者在高纬度地区占主导地位。我们表明，JULES能够真实地代表全球碳（C）循环的几个方面。模拟的总初级生产力（GPP）在观测范围内，但模拟的净初级生产力（NPP）略高。从1982年到2011年，JULES的GPP为133 PgC yr（-1），而基于观测的估计（在同一时期）在123 +/- 8和150-175 PgC yr（-1）之间。2000年至2013年的NPP为72 Pg C yr（-1），而同期卫星得出的NPP为55 Pg Cyr（-1），独立估计值为56.2 +/- 14.3 Pg C yr（-1）。植被中储存的模拟碳为542 PgC，而基于观测的范围为400-600 PgC。土壤碳是远远低于（1422 Pg C）从测量（> 2400 Pg C）的估计，在热带和寒带forests.We土壤碳大大低估了历史陆地碳汇的一些方面，模拟JULES。在1900年代至2000年代，大气中二氧化碳含量的增加提高了植被的生产力，增加了土壤中的废弃物，而土地使用的变化则使植被消失，土壤碳减少。结果是模拟土壤碳增加57 Pg C，但植被碳减少98 Pg C。从1900年到2009年，由于土地利用变化造成的土壤和植被碳的模拟损失总量为138 PgC，而最近的观测约束估计为1901年至2012年的155 +/- 50 PgC。从2000年到2009年，模拟的陆地碳汇为2.0 +/- 1.0 PgC yr（-1），与IPCC和全球碳项目的估计非常一致。
Dynamic global vegetation models (DGVMs) are used for studying historical and future changes to vegetation and the terrestrial carbon cycle. JULES (the Joint UK Land Environment Simulator) represents the land surface in the Hadley Centre climate models and in the UK Earth System Model. Recently the number of plant functional types (PFTs) in JULES was expanded from five to nine to better represent functional diversity in global ecosystems. Here we introduce a more mechanistic representation of vegetation dynamics in TRIFFID, the dynamic vegetation component of JULES, which allows for any number of PFTs to compete based solely on their height; therefore, the previous hard-wired dominance hierarchy is removed.With the new set of nine PFTs, JULES is able to more accurately reproduce global vegetation distribution compared to the former five PFT version. Improvements include the coverage of trees within tropical and boreal forests and a reduction in shrubs, the latter of which dominated at high latitudes. We show that JULES is able to realistically represent several aspects of the global carbon (C) cycle. The simulated gross primary productivity (GPP) is within the range of observations, but simulated net primary productivity (NPP) is slightly too high. GPP in JULES from 1982 to 2011 is 133 PgC yr(-1), compared to observation-based estimates (over the same time period) between 123 +/- 8 and 150-175 PgC yr(-1). NPP from 2000 to 2013 is 72 Pg C yr(-1), compared to satellite-derived NPP of 55 Pg Cyr(-1) over the same period and independent estimates of 56.2 +/- 14.3 PgC yr(-1). The simulated carbon stored in vegetation is 542 PgC, compared to an observation-based range of 400-600 PgC. Soil carbon is much lower (1422 Pg C) than estimates from measurements ( > 2400 Pg C), with large underestimations of soil carbon in the tropical and boreal forests.We also examined some aspects of the historical terrestrial carbon sink as simulated by JULES. Between the 1900s and 2000s, increased atmospheric carbon dioxide levels enhanced vegetation productivity and litter inputs into the soils, while land use change removed vegetation and reduced soil carbon. The result is a simulated increase in soil carbon of 57 Pg C but a decrease in vegetation carbon of 98 Pg C. The total simulated loss of soil and vegetation carbon due to land use change is 138 PgC from 1900 to 2009, compared to a recent observationally constrained estimate of 155 +/- 50 PgC from 1901 to 2012. The simulated land carbon sink is 2.0 +/- 1.0 PgC yr(-1) from 2000 to 2009, in close agreement with estimates from the IPCC and Global Carbon Project.