Tropical extreme droughts drive long-term increase in atmospheric CO(2) growth rate variability.
Tropical extreme droughts drive long-term increase in atmospheric CO(2) growth rate variability.
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DOI：
10.1038/s41467-022-28824-5
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发表时间：
2022-03-07
影响因子：
16.6
通讯作者：
Keenan TF
中科院分区：
文献类型：
--
作者：
Luo X;Keenan TF
陆地碳汇吸收了大约 30% 的人为二氧化碳排放量，减缓了大气中二氧化碳 (CO2) 的积累，但每年的变化很大。由此产生的大气二氧化碳增长率（CGR）的变化与热带温度和水资源供应有关。 CGR 对热带温度 () 的明显敏感性在过去六十年中发生了显着变化，然而，迄今为止观测的驱动因素仍不清楚。在这里，我们利用大气观测、多种全球植被模型和机器学习产品来分析敏感性变化的原因。我们发现，由于 CGR 变异幅度（即以 CGR 的一个标准差；STDCGR 表示）的长期变化，出现了三倍的增长，从 1960-1979 年到 1985-2004 年增加了 34.7%，随后在 1997-2016 年下降了 14.4%。我们发现 STDCGR 与受极端干旱影响的热带植被区域（23°S – 23°N）之间存在密切关系（r2 = 0.75，p < 0.01），极端干旱影响了 6-9% 的热带植被表面。受极端干旱影响的热带地区每增加 1%，STDCGR 就会增加约 0.14 Pg C yr−1。 STDCGR的历史变化主要以非洲和亚洲热带极端干旱地区以及半干旱生态系统为主。极端干旱对一小部分植被表面的巨大影响放大了 CGR 的年际变化，并解释了观察到的长期动态。在过去的六十年中，大气二氧化碳增长率的表观温度敏感性显着增加，但这种增加仍然无法解释。在这里，我们表明热带极端干旱放大了大气二氧化碳增长率的年际变化并驱动了敏感性变化。
The terrestrial carbon sink slows the accumulation of carbon dioxide (CO2) in the atmosphere by absorbing roughly 30% of anthropogenic CO2 emissions, but varies greatly from year to year. The resulting variations in the atmospheric CO2 growth rate (CGR) have been related to tropical temperature and water availability. The apparent sensitivity of CGR to tropical temperature () has changed markedly over the past six decades, however, the drivers of the observation to date remains unidentified. Here, we use atmospheric observations, multiple global vegetation models and machine learning products to analyze the cause of the sensitivity change. We found that a threefold increase in emerged due to the long-term changes in the magnitude of CGR variability (i.e., indicated by one standard deviation of CGR; STDCGR), which increased 34.7% from 1960-1979 to 1985-2004 and subsequently decreased 14.4% in 1997-2016. We found a close relationship (r2 = 0.75, p < 0.01) between STDCGR and the tropical vegetated area (23°S – 23°N) affected by extreme droughts, which influenced 6-9% of the tropical vegetated surface. A 1% increase in the tropical area affected by extreme droughts led to about 0.14 Pg C yr−1 increase in STDCGR. The historical changes in STDCGR were dominated by extreme drought-affected areas in tropical Africa and Asia, and semi-arid ecosystems. The outsized influence of extreme droughts over a small fraction of vegetated surface amplified the interannual variability in CGR and explained the observed long-term dynamics of . The apparent temperature sensitivity of atmospheric CO2 growth rate has increased markedly over the past six decades, however, the increase remains unexplained. Here we show that tropical extreme droughts amplified the interannual variability in atmospheric CO2 growth rate and drove the sensitivity change.
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影响因子：
64.8
作者：
Green, Julia K.;Seneviratne, Sonia I.;Gentine, Pierre
通讯作者：
Gentine, Pierre
DOI：
10.1073/pnas.0935903100
发表时间：
2003-05-13
影响因子：
11.1
作者：
Clark, DA;Piper, SC;Clark, DB
通讯作者：
Clark, DB
影响因子：
56.9
作者：
Bousquet, P;Peylin, P;Tans, PP
通讯作者：
Tans, PP
DOI：
10.1073/pnas.1521479112
发表时间：
2015-12-22
影响因子：
11.1
作者：
Anderegg, William R. L.;Ballantyne, Ashley P.;Pacala, Stephen W.
通讯作者：
Pacala, Stephen W.
DOI：
10.1002/joc.3711
发表时间：
2014-03-15
期刊：
INTERNATIONAL JOURNAL OF CLIMATOLOGY
影响因子：
--
作者：
Harris, I.;Jones, P. D.;Lister, D. H.
通讯作者：
Lister, D. H.