Global distribution of C3 and C4 vegetation:: Carbon cycle implications -: art. no. 1006
Global distribution of C3 and C4 vegetation:: Carbon cycle implications -: art. no. 1006
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DOI：
10.1029/2001gb001807
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发表时间：
2003-01-10
影响因子：
5.2
通讯作者：
DeFries, RS
中科院分区：
文献类型：
--
作者：
Still, CJ;Berry, JA;DeFries, RS
准确模拟陆地表面与大气之间的二氧化碳、水和能量交换需要了解C - 3和C - 4植物的全球分布。由于每种光合类型所表现出的明显分馏作用，了解C - 3/C - 4的分布对于模拟大气二氧化碳的碳同位素组成也很重要。陆地表面的大片区域是两种光合类型在空间和时间上的镶嵌体。我们通过结合遥感产品、生理模型、全球作物比例的空间分布以及主要作物类型的全国收获面积数据，开发了一种捕捉这种异质性的方法。我们的C - 3/C - 4分布预测C4植被的全球覆盖面积为1880万平方千米，而C - 3植被覆盖8740万平方千米。我们将我们的分布纳入SiB2模型，并模拟了每种光合类型的碳通量。C4植物的总初级生产力（GPP）为35.3拍克碳/年，约占总GPP的23%，而C - 3植物的总初级生产力为114.7拍克碳/年。对（二氧化碳）- C - 13的同化加权陆地判别值为千分之16.5。如果碳汇的陆地部分与GPP成正比，那么使用C - 13预算方法和20世纪90年代的平均碳循环参数值，这意味着陆地净吸收2.4拍克碳/年，海洋净吸收1.4拍克碳/年。我们还使用CASA模型模拟了每种光合类型的生物量。C - 3和C - 4植被的模拟生物量值分别为389.3拍克碳和18.6拍克碳。
The global distribution of C-3 and C-4 plants is required for accurately simulating exchanges of CO2, water, and energy between the land surface and atmosphere. It is also important to know the C-3/C-4 distribution for simulations of the carbon isotope composition of atmospheric CO2 owing to the distinct fractionations displayed by each photosynthetic type. Large areas of the land surface are spatial and temporal mosaics of both photosynthetic types. We developed an approach for capturing this heterogeneity by combining remote sensing products, physiological modeling, a spatial distribution of global crop fractions, and national harvest area data for major crop types. Our C-3/C-4 distribution predicts the global coverage of C4 vegetation to be 18.8 million km(2), while C-3 vegetation covers 87.4 million km(2). We incorporated our distribution into the SiB2 model and simulated carbon fluxes for each photosynthetic type. The gross primary production (GPP) of C4 plants is 35.3 Pg C yr(-1), or similar to23% of total GPP, while that of C-3 plants is 114.7 Pg C yr(-1). The assimilation-weighted terrestrial discrimination against (CO2)-C-13 is 16.5parts per thousand. If the terrestrial component of the carbon sink is proportional to GPP, this implies a net uptake of 2.4 Pg C yr(-1) on land and 1.4 Pg C yr(-1) in the ocean using a C-13 budgeting approach and average carbon cycle parameter values for the 1990s. We also simulated the biomass of each photosynthetic type using the CASA model. The simulated biomass values of C-3 and C-4 vegetation are 389.3 and 18.6 Pg C, respectively.