Quantifying pyro-convective injection heights via obervation of fire energy emissions, and assessing the impact on forward and inversion modelling

通过观察火能排放来量化热对流注入高度，并评估对正演和反演建模的影响

• 批准号: NE/E016863/1
• 负责人: Martin Wooster
• 金额: $ 32.42万
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FE016863%2F1
• 关键词: Quantifying; pyro; convective; injection; heights

Biomass burning is a major dynamic of the Earth system, and the wildfires involved emit copious quantities of smoke made up of trace gases such as carbon monoxide and particulates such as black carbon. For some species, the total emissions from biomass burning represent amongst the largest single emissions source, but the spatial location of the individual fires and the exact amounts of species emitted are highly variable in both space and time. Use of satellite Earth Observation (EO) data are generally considered to be critical in providing the temporal coverage and spatial sampling necessary for an understanding of these highly variable emissions sources. Once aloft, air currents transport the smoke emissions, affecting their longevity, chemical conversion and fate. Chemical transport models (CTMs) are used to quantify these processes, but unlike all other emissions (except those from aircraft) fires may inject their smoke plumes into various heights in the troposphere and occasionally even lower stratosphere by virtue of the intense heat and convection produced by the burning fuel. Emissions remnants from certain tropical fires have been observed at 15 km altitude, and smoke plumes of individual Canadian stand-replacing forest fires can approach such heights. CTMs require an estimate of emissions injection height in order to correctly prescribe the interaction between the BB plumes and the global atmosphere, but at present there is very little information on this parameter since the 'standard' satellite-EO data on burned area and active fire 'hotspot' detections provides little relevant information. Because of this, CTM runs often assume a single fixed altitude for all BB emissions, usually presuming that all pollutants are contained solely within the lower troposphere or perhaps even the planetary boundary layer. This is clearly unrealistic since many wildfires can be seen capped by a large convective smoke plume rising to many km altitude, but because of a lack of satellite data and methods with which to better parameterise the actual injection height the topic has received far less attention than has estimation of the magnitude and variability of the emissions sources themselves. However, a number of recent key studies have determined the very serious implications that incorrectly prescribed emissions injection heights have for the ability of CTMs to correctly represent emissions transport and fate. Similar problems, causing a currently unknown degree of error, will affect 'top-down' emission estimates based on the inversion of observed atmospheric concentrations of BB species. Experiments have indicated that it is the energy released by a fire that drives the convective updraft responsible for the elevated injection of the smoke emissions. New satellite observations of the energy released by fires therefore offer an excellent opportunity to develop a testable model for pyrogenic injection heights that can be used to supplement current BB datasets on emissions source strength and location, by allowing information on injection altitude to also be derived and used in CTM runs and inversion studies. The aim of this proposal is therefore to develop and test a methodology for using satellite EO to greatly improve the current prescriptions of plume injection heights that are a mandatory field required to model biomass burning emissions in CTMs, and are necessary when inverting the chemistry and transport associated with BB trace gases to infer the magnitude and variability of emissions sources. A new model relating injection height and the vertical distribution of smoke constituents will be a key output from this research, along with a injection height 'climatology' database describing the frequency of elevated injections heights and their spatio-temporal variation across BB affected regions.

生物质燃烧是地球系统的一个主要动力，所涉及的野火会释放出大量的烟雾，这些烟雾由一氧化碳等微量气体和黑碳等微粒组成。对某些物种来说，生物质燃烧的总排放量是最大的单一排放源之一，但个别火灾的空间位置和所排放物种的确切数量在空间和时间上变化很大。一般认为，使用卫星地球观测数据对于提供了解这些高度可变的排放源所需的时间覆盖面和空间取样至关重要。一旦上升，气流就会输送烟雾排放物，影响它们的寿命、化学转化和命运。化学传输模型（CTM）被用来量化这些过程，但与所有其他排放物（除了来自飞机的排放物）不同的是，火灾可能会将其烟雾羽流注入对流层的不同高度，有时甚至会由于燃烧燃料产生的强烈热量和对流而进入平流层下部。在15公里的高度观测到某些热带火灾的排放残留物，加拿大个别取代林分的森林火灾的烟羽可以达到这样的高度。CTM需要对排放物注入高度进行估计，以便正确地说明BB羽流与全球大气之间的相互作用，但目前关于这一参数的信息很少，因为“标准”卫星-EO关于燃烧面积和活跃火灾“热点”探测的数据提供的相关信息很少。正因为如此，CTM运行通常假设所有BB排放都在一个固定的高度，通常假设所有污染物都只包含在对流层低层甚至行星边界层中。这显然是不现实的，因为许多野火可以被上升到许多公里高度的大对流烟羽所覆盖，但由于缺乏卫星数据和方法来更好地参数化实际喷射高度，该主题受到的关注远远低于对排放源本身的大小和可变性的估计。然而，最近的一些关键研究已经确定了非常严重的影响，不正确规定的排放注入高度的能力的CTM正确地代表排放传输和命运。类似的问题，造成目前未知程度的错误，将影响'自上而下'的排放量估计的基础上反演观测大气中的BB物种的浓度。实验表明，正是火灾释放的能量驱动了对流上升气流，导致烟雾排放量增加。因此，新的卫星观测火灾释放的能量提供了一个很好的机会，开发一个可测试的模型，可用于补充目前的BB数据集的排放源强度和位置，通过允许注入高度的信息也可以派生和用于CTM运行和反演研究。因此，本建议的目的是开发和测试一种方法，利用卫星EO大大改善目前的规定羽流喷射高度，这是一个强制性的领域，需要模拟生物质燃烧排放量的CTM，是必要的，当反转的化学和运输与BB痕量气体，以推断排放源的大小和可变性。一个新的模型相关的注入高度和烟雾成分的垂直分布将是一个关键的输出，从这项研究，沿着注入高度的“气候学”数据库描述的频率升高的注入高度和他们的时空变化在BB受影响的地区。

项目成果

Fire evolution in the radioactive forests of Ukraine and Belarus: future risks for the population and the environment

• DOI: 10.1890/14-1227.1
• 发表时间: 2015-02-01
• 期刊: ECOLOGICAL MONOGRAPHS
• 影响因子: 6.1
• 作者: Evangeliou, N.;Balkanski, Y.;Moller, A. P.
• 通讯作者: Moller, A. P.

Quantifying pyroconvective injection heights using observations of fire energy: sensitivity of spaceborne observations of carbon monoxide

• DOI: 10.5194/acp-15-4339-2015
• 发表时间: 2015-01-01
• 期刊: ATMOSPHERIC CHEMISTRY AND PHYSICS
• 影响因子: 6.3
• 作者: Gonzi, S.;Palmer, P. I.;Deeter, M. N.
• 通讯作者: Deeter, M. N.