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Nation-wide estimation of groundwater redox conditions and nitrate concentrations through machine learning 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (6)
作者:  Knoll, Lukas;  Breuer, Lutz;  Bach, Martin
收藏  |  浏览/下载:36/0  |  提交时间:2020/07/02
groundwater quality  nitrate pollution  redox conditions  random forest  uncertainty  large-scale  
Millennial-scale hydroclimate control of tropical soil carbon storage 期刊论文
NATURE, 2020, 581 (7806) : 63-+
作者:  Lam, Tommy Tsan-Yuk;  Jia, Na;  Zhang, Ya-Wei;  Shum, Marcus Ho-Hin;  Jiang, Jia-Fu;  Zhu, Hua-Chen;  Tong, Yi-Gang;  Shi, Yong-Xia;  Ni, Xue-Bing;  Liao, Yun-Shi;  Li, Wen-Juan;  Jiang, Bao-Gui;  Wei, Wei;  Yuan, Ting-Ting;  Zheng, Kui;  Cui, Xiao-Ming;  Li, Jie;  Pei, Guang-Qian
收藏  |  浏览/下载:72/0  |  提交时间:2020/05/13

Over the past 18,000 years, the residence time and amount of soil carbon stored in the Ganges-Brahmaputra basin have been controlled by the intensity of Indian Summer Monsoon rainfall, with greater carbon destabilization during wetter, warmer conditions.


The storage of organic carbon in the terrestrial biosphere directly affects atmospheric concentrations of carbon dioxide over a wide range of timescales. Within the terrestrial biosphere, the magnitude of carbon storage can vary in response to environmental perturbations such as changing temperature or hydroclimate(1), potentially generating feedback on the atmospheric inventory of carbon dioxide. Although temperature controls the storage of soil organic carbon at mid and high latitudes(2,3), hydroclimate may be the dominant driver of soil carbon persistence in the tropics(4,5)  however, the sensitivity of tropical soil carbon turnover to large-scale hydroclimate variability remains poorly understood. Here we show that changes in Indian Summer Monsoon rainfall have controlled the residence time of soil carbon in the Ganges-Brahmaputra basin over the past 18,000 years. Comparison of radiocarbon ages of bulk organic carbon and terrestrial higher-plant biomarkers with co-located palaeohydrological records(6) reveals a negative relationship between monsoon rainfall and soil organic carbon stocks on a millennial timescale. Across the deglaciation period, a depletion of basin-wide soil carbon stocks was triggered by increasing rainfall and associated enhanced soil respiration rates. Our results suggest that future hydroclimate changes in tropical regions are likely to accelerate soil carbon destabilization, further increasing atmospheric carbon dioxide concentrations.


  
Signatures of self-organized criticality in an ultracold atomic gas 期刊论文
NATURE, 2020, 577 (7791) : 481-+
作者:  MacPherson, Laura;  Anokye, Juliana;  Yeung, Miriam M.;  Lam, Enid Y. N.;  Chan, Yih-Chih;  Weng, Chen-Fang;  Yeh, Paul;  Knezevic, Kathy;  Butler, Miriam S.;  Hoegl, Annabelle;  Chan, Kah-Lok;  Burr, Marian L.;  Gearing, Linden J.;  Willson, Tracy;  Liu, Joy;  Choi, Jarny;  Yang, Yuqing;  Bilardi, Rebecca A.;  Falk, Hendrik;  Nghi Nguyen;  Stupple, Paul A.;  Peat, Thomas S.;  Zhang, Ming;  De Silva, Melanie;  Carrasco-Pozo, Catalina;  Avery, Vicky M.;  Khoo, Sim;  Dolezal, Olan;  Dennis, Matthew L.;  Nuttall, Stewart;  Surjadi, Regina;  Newman, Janet;  Ren, Bin;  Leaver, David J.;  Sun, Yuxin;  Baell, Jonathan B.;  Dovey, Oliver;  Vassiliou, George S.;  Grebien, Florian;  Dawson, Sarah-Jane;  Street, Ian P.;  Monahan, Brendon J.;  Burns, Christopher J.;  Choudhary, Chunaram;  Blewitt, Marnie E.;  Voss, Anne K.;  Thomas, Tim;  Dawson, Mark A.
收藏  |  浏览/下载:66/0  |  提交时间:2020/07/03

Self-organized criticality is an elegant explanation of how complex structures emerge and persist throughout nature(1), and why such structures often exhibit similar scale-invariant properties(2-9). Although self-organized criticality is sometimes captured by simple models that feature a critical point as an attractor for the dynamics(10-15), the connection to real-world systems is exceptionally hard to test quantitatively(16-21). Here we observe three key signatures of self-organized criticality in the dynamics of a driven-dissipative gas of ultracold potassium atoms: self-organization to a stationary state that is largely independent of the initial conditions  scale-invariance of the final density characterized by a unique scaling function  and large fluctuations of the number of excited atoms (avalanches) obeying a characteristic power-law distribution. This work establishes a well-controlled platform for investigating self-organization phenomena and non-equilibrium criticality, with experimental access to the underlying microscopic details of the system.


A driven-dissipative gas of ultracold potassium atoms is used to demonstrate three key signatures of self-organized criticality, and provides a system in which the phenomenon can be experimentally tested.


  
Is there a quiescent typhoon season over the western North Pacific following a strong El Nino event? 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2019, 39 (1) : 61-73
作者:  Wang, Chao;  Wu, Liguang;  Zhao, Haikun;  Cao, Jian;  Tian, Wei
收藏  |  浏览/下载:28/0  |  提交时间:2019/04/09
genesis frequency  large-scale conditions  strong El Nino ensuing TC season  
Duration, rarity, affected area, and weather types associated with extreme precipitation in the Ore Mountains (Erzgebirge) region, Central Europe 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2017, 37 (12)
作者:  Minarova, Jana;  Muller, Miloslav;  Clappier, Alain;  Hansel, Stephanie;  Hoy, Andreas;  Matschullat, Jorg;  Kaspar, Marek
收藏  |  浏览/下载:30/0  |  提交时间:2019/04/09
Krune hory  heavy rainfall  WEI  synoptic conditions  trend analysis  Grosswetterlagen (large-scale weather pattern)