Underestimation of Global Photosynthesis in Earth System Models Due to Representation of Vegetation Structure
Underestimation of Global Photosynthesis in Earth System Models Due to Representation of Vegetation Structure
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DOI：
10.1029/2018gb006135
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发表时间：
2019-11-08
影响因子：
5.2
通讯作者：
Chen, J. M.
中科院分区：
文献类型：
--
作者：
Braghiere, R. K.;Quaife, T.;Chen, J. M.
植被结构对地球系统模式（ESMs）短波辐射吸收的影响对于碳循环的精确模拟和气候预估具有潜在的重要意义。植物利用一部分入射的短波辐射进行光合作用，而冠层结构对吸收的短波辐射有直接影响。本文评估了当结合卫星数据得出的团块时，模拟的陆地生物圈碳同化是如何受到影响的。我们利用联合英国陆地环境模拟器（Joint UK Land Environment Simulator，英国地球系统模式的陆地表面方案）评估了丛集对光合作用的影响。在全球范围内，总初级生产力（GPP）增加了5.53 +/- 1.02 PgC/年，其中热带地区的绝对增加幅度最大。这与先前的研究相反，先前的研究表明，当使用类似的聚集数据集来修改模型中的光拦截时，光合作用会减少。在我们的研究中，光通过上层冠层的额外透射导致低层吸收增强，而低层的光合作用往往受到光的限制。结果表明，这一结果与所采用的冠层方案的复杂性有关。
The impact of vegetation structure on the absorption of shortwave radiation in Earth System Models (ESMs) is potentially important for accurate modeling of the carbon cycle and hence climate projections. A proportion of incident shortwave radiation is used by plants to photosynthesize and canopy structure has a direct impact on the fraction of this radiation which is absorbed. This paper evaluates how modeled carbon assimilation of the terrestrial biosphere is impacted when clumping derived from satellite data is incorporated. We evaluated impacts of clumping on photosynthesis using the Joint UK Land Environment Simulator, the land surface scheme of the UK Earth System Model. At the global level, Gross Primary Productivity (GPP) increased by 5.53 +/- 1.02 PgC/year with the strongest absolute increase in the tropics. This is contrary to previous studies that have shown a decrease in photosynthesis when similar clumping data sets have been used to modify light interception in models. In our study additional transmission of light through upper canopy layers leads to enhanced absorption in lower layers in which photosynthesis tends to be light limited. We show that this result is related to the complexity of canopy scheme being used.