Biomass combustion produces ice-active minerals in biomass-burning aerosol and bottom ash
Biomass combustion produces ice-active minerals in biomass-burning aerosol and bottom ash
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DOI：
10.1073/pnas.1922128117
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发表时间：
2020-09-08
影响因子：
11.1
通讯作者：
Sullivan, Ryan C.
中科院分区：
文献类型：
--
作者：
Jahn, Leif G.;Polen, Michael J.;Sullivan, Ryan C.
冰成核及其导致的云冰川作用是影响云的演化及其辐射强迫和降水等性质的重要大气过程，但大气冰成核剂的来源和性质却没有得到很好的限制。由冰成核粒子（INPs）引起的非均匀冰成核使云在温度高于开始于-35摄氏度附近的均匀冻结制度时能够结冰。生物质燃烧是大气颗粒物的一个重要全球来源，也是一个高度可变且知之甚少的INPs来源。这些INPs的性质以及它们与燃料成分及其燃烧的关系是我们理解生物质燃烧对环境和气候影响的关键差距。在这里，我们表明，燃烧过程中转化的无机元素自然存在于生物质（不是土壤或灰尘），形成潜在的冰活性矿物在底灰和排放的气溶胶颗粒。这些粒子具有足够高的冰成核活性，与混合相云相关，并且在很宽的温度范围内都是活跃的，在高达-13摄氏度的温度下成核冰。因此，某些无机元素可以作为预测燃料中冰核生成的指标。除了蓬松的原生土壤和尘埃颗粒之外，燃烧衍生的矿物是天然生物质燃烧气溶胶排放中INPs的一个重要但未得到充分研究的来源。这些发现和见解应该推动将生物质燃烧的INPs实际纳入大气云和气候模型。还应研究生物质燃烧气溶胶中产生的这些矿物成分与其他大气化学过程的关系，例如促进多相化学反应和养分供应。
Ice nucleation and the resulting cloud glaciation are significant atmospheric processes that affect the evolution of clouds and their properties including radiative forcing and precipitation, yet the sources and properties of atmospheric ice nucleants are poorly constrained. Heterogeneous ice nucleation caused by ice-nucleating particles (INPs) enables cloud glaciation at temperatures above the homogeneous freezing regime that starts near -35 degrees C. Biomass burning is a significant global source of atmospheric particles and a highly variable and poorly understood source of INPs. The nature of these INPs and how they relate to the fuel composition and its combustion are critical gaps in our understanding of the effects of biomass burning on the environment and climate. Here we show that the combustion process transforms inorganic elements naturally present in the biomass (not soil or dust) to form potentially ice-active minerals in both the bottom ash and emitted aerosol particles. These particles possess ice-nucleation activities high enough to be relevant to mixed-phase clouds and are active over a wide temperature range, nucleating ice at up to -13 degrees C. Certain inorganic elements can thus serve as indicators to predict the production of ice nucleants from the fuel. Combustion-derived minerals are an important but understudied source of INPs in natural biomass-burning aerosol emissions in addition to lofted primary soil and dust particles. These discoveries and insights should advance the realistic incorporation of biomass-burning INPs into atmospheric cloud and climate models. These mineral components produced in biomass-burning aerosol should also be studied in relation to other atmospheric chemistry processes, such as facilitating multiphase chemical reactions and nutrient availability.