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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Interannual variability in the global carbon cycle
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Interannual variability in the global carbon cycle

机译：全球碳循环的年际变化

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The annual growth rate of atmospheric CO2 has varied between 1 and 5 Pg C yr(-1) over the last decades. Most of this variation is associated with terrestrial and oceanic exchanges of carbon which seem to vary independently. Three processes contribute to the annual flux of carbon from terrestrial ecosystems: changes in land use, natural disturbances, and metabolic changes caused by variations in climate. Because rates of land-use change are often not available on an annual basis, estimates of the flux of carbon attributable to land use change may underestimate year-to-year variability. Limited data reviewed here suggest that the interannual variability of this flux: is generally small for two reasons. First. although rates of land use change may vary substantially from year to year at a local scale, variability is generally less at regional and global scales because high rates of deforestation in one area do not necessarily coincide with high rates in other areas. Second, less than 50% of the carbon lost to the atmosphere as a result of land use change is lost in the year of disturbance; the rest is released in subsequent years. The interannual variability of the flux of carbon from land use change is thus less variable than rates of land use change and probably accounts, globally, for less than 5-10% of the observed variation in the annual growth rate of CO2 in the atmosphere. Natural disturbances are estimated to account for a similar fraction of the variation. The most important contributor appears to be the effect of short-term changes in climate (temperature and precipitation) on terrestrial metabolism, Over the period 1980-1995, year-to-year differences in the flux of carbon from terrestrial metabolism have almost been as large as variations in the growth rate of atmospheric CO2. [References: 40]
机译：在过去的几十年中，大气中二氧化碳的年增长率在1-5 Pg C yr（-1）之间变化。这种变化大部分与陆地和海洋碳交换有关，而碳的交换似乎是独立变化的。陆地生态系统每年产生的碳通量有三个过程：土地利用的变化，自然干扰以及气候变化引起的代谢变化。由于通常无法每年获得土地使用变化的速率，因此对因土地使用变化而导致的碳通量的估算可能会低估逐年的可变性。此处审查的有限数据表明该通量的年际变化：通常有两个较小的原因。第一。尽管在地方范围内，土地使用变化的速率每年可能有很大的不同，但是在区域和全球范围内变化通常较小，因为一个地区的高森林砍伐率不一定与其他地区的高率一致。其次，在土地扰乱的年份中，由于土地用途的变化而损失到大气中的碳损失不到50％;其余的将在随后的几年中发布。因此，来自土地利用变化的碳通量的年际变化不如土地利用变化的变化多，并且可能在全球范围内占大气中二氧化碳年增长率观察到的变化的不到5-10％。估计自然干扰可解释变化的相似部分。最重要的因素似乎是气候（温度和降水）的短期变化对陆地代谢的影响。在1980-1995年期间，陆地代谢产生的碳通量的逐年差异几乎与随大气CO2增长率的变化而变大。 [参考：40]

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