Parameterizing agricultural fires inducing mineral dust emission

参数化引起矿物粉尘排放的农业火灾

• 批准号: 432456920
• 负责人: Professorin Dr. Kerstin Schepanski
• 金额: --
• 依托单位: Institut für Meteorologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/432456920?language=en
• 关键词: Parameterizing; agricultural; fires; inducing; mineral

Aerosol, tiny particles suspended in the atmosphere, is ubiquitous in atmosphere and takes part in many climate-relevant processes determining the Earth energy budget and ultimately the Earth thermostat. However, large uncertainties are still associated with aerosol source description, emission, and feedback processes limiting the accuracy of Earth system models and climate projections.Aerosol is divers regarding its sources, properties and impact. Natural aerosol is emitted from natural sources like deserts where bare soil is prone to wind erosion. Carbonaceous combustion aerosol is emitted from wild fires fueled by vegetation. Both mineral dust aerosol particle, entrained into the atmosphere by wind, and carbonaceous aerosol injected into the atmosphere by the fire's pyro-convective updraft, is a naturally occurring process, but can also be induced by human activity. E.g. agricultural land use can increase the land surface's susceptibility to wind erosion. Land management practices such as prescribed fires lit to burn-off vegetation residues significantly contribute to the local atmospheric burden of combustion aerosols. Furthermore, the burn-off of vegetation residues increases the wind erosion potential in two ways: First, the removal of vegetation increases the surface's susceptibility to wind erosion. Second, the pyro-convection enhances the ambient wind field and increases the atmospheric turbulence, which increases the wind-driven dust entrainment.In the light of the complexity of environmental conditions and processes controlling and driving natural aerosol emission, investigations on the emission process and its accurate representation in mathematical-physical models is inevitable. Although individual parameterizations for different aerosol emission processes exists, they are used mutually independent. The joint consideration is in particular relevant for prescribed fires in agricultural regions, where the vegetation otherwise inhibits wind erosion. To address this missing link, the project aims at developing a parameterization suite describing mineral dust emission induced by agricultural fires, which will be tested for south-east Australia. There, agricultural fires and wind erosion are common phenomena.

气溶胶是悬浮在大气中的微小颗粒物，在大气中普遍存在，并参与许多与气候相关的过程，决定着地球的能量收支，最终决定着地球的温度。然而，气溶胶的来源描述、排放和反馈过程仍然存在很大的不确定性，这限制了地球系统模式和气候预测的准确性。天然气溶胶是从沙漠等自然来源排放出来的，沙漠中裸露的土壤容易受到风蚀。含碳燃烧气溶胶是由植被燃烧的野火释放出来的。矿物粉尘气溶胶颗粒，夹带到大气中的风，和碳气溶胶注入到大气中的火灾的热对流上升气流，是一个自然发生的过程，但也可以由人类活动引起的。例如，农业用地会增加土地表面对风蚀的敏感性。土地管理做法，如规定的火点燃烧掉植被残留物，大大有助于当地大气燃烧气溶胶的负担。此外，植被残留物的燃烧在两个方面增加了风蚀的可能性：第一，植被的清除增加了地表对风蚀的敏感性。其次，热对流增强了环境风场，增加了大气湍流，从而增加了风沙的卷吸作用，由于控制和驱动气溶胶释放的环境条件和过程的复杂性，研究气溶胶释放过程及其在物理模式中的精确表达是必然的。虽然存在针对不同气溶胶排放过程的单独参数化，但它们是相互独立使用的。联合考虑特别适用于农业地区的规定火灾，因为那里的植被可以抑制风蚀。为了解决这一缺失环节，该项目旨在开发一套参数化程序，描述农业火灾引起的矿物粉尘排放，将在澳大利亚东南部进行测试。在那里，农业火灾和风蚀是常见的现象。