The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the inter...The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the interplay of climate,soil and vegetation type.Here,we synthesized currently available soil carbon data to show that mean organic carbon density in the topsoil(0-10 cm)in TP grassland(3.12±0.52 kg C m^(-2))is less than half of that in Arctic tundra(6.70±1.94 kg C m^(-2)).Such difference is primarily attributed to their difference in radiocarbon-inferred soil carbon turnover times(547 years for TP grassland versus 1609 years for Arctic tundra)rather than to their marginal difference in topsoil carbon inputs.Our findings highlight the importance of improving regional-specific soil carbon turnover and its controlling mechanisms across permafrost affected zones in ecosystem models to fully represent carbon-climate feedback.展开更多
提出了一种用于网络测量的动态时间驱动分组采样技术,根据网络流量的变化动态调整采样次数,从而能将最后的测量误差率控制在一个给定的范围内,在保证精度的同时极大地降低了测量的代价。并且该方法的实现复杂度与“1out of N”采样技术...提出了一种用于网络测量的动态时间驱动分组采样技术,根据网络流量的变化动态调整采样次数,从而能将最后的测量误差率控制在一个给定的范围内,在保证精度的同时极大地降低了测量的代价。并且该方法的实现复杂度与“1out of N”采样技术近似,文章中给出了有关的理论分析和实验研究。实验结果表明该方法达到了设计的目标。根据网络运行状态动态调整网络测量方案的思想可以广泛用于网络测量当中。展开更多
基金This work was supported by Preliminary Research on Three Poles Environment and Climate Change(2019YFC1509103)the National Natural Science Foundation of China(41861134036 and 41922004)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0606)the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA19070303 and XDA20050101).
文摘The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the interplay of climate,soil and vegetation type.Here,we synthesized currently available soil carbon data to show that mean organic carbon density in the topsoil(0-10 cm)in TP grassland(3.12±0.52 kg C m^(-2))is less than half of that in Arctic tundra(6.70±1.94 kg C m^(-2)).Such difference is primarily attributed to their difference in radiocarbon-inferred soil carbon turnover times(547 years for TP grassland versus 1609 years for Arctic tundra)rather than to their marginal difference in topsoil carbon inputs.Our findings highlight the importance of improving regional-specific soil carbon turnover and its controlling mechanisms across permafrost affected zones in ecosystem models to fully represent carbon-climate feedback.
文摘提出了一种用于网络测量的动态时间驱动分组采样技术,根据网络流量的变化动态调整采样次数,从而能将最后的测量误差率控制在一个给定的范围内,在保证精度的同时极大地降低了测量的代价。并且该方法的实现复杂度与“1out of N”采样技术近似,文章中给出了有关的理论分析和实验研究。实验结果表明该方法达到了设计的目标。根据网络运行状态动态调整网络测量方案的思想可以广泛用于网络测量当中。
