How does land use impact on global air quality and climate: a combined satellite and model study

背景和动因粮食安全和人口增长带来的未来压力导致了人为土地利用的变化。土地利用的变化通过改变气体和气溶胶物种的自然排放来影响空气质量，并通过辐射强迫来影响气候。这是因为土地利用的变化改变了大气-生物圈的相互作用，从而影响了辐射、水分和碳的收支。植被还排放生物来源的挥发性有机化合物(BVOCs)，形成二次有机气溶胶(SOA)，改变主要空气污染物、颗粒物(PM2.5)和臭氧的水平，并影响丰富的短期气候作用力(SLCFs)。此外，土地利用的变化往往是由火灾和生物质燃烧引起的，这也会导致空气质量变差，并影响气候。了解当前和未来的土地利用变化，如大规模砍伐森林，如何影响大气成分和辐射，对于解决空气质量差和减缓气候变化的全球努力至关重要。一个关键的不确定性是我们对土地利用变化如何通过BVOC排放和SOA形成的变化影响空气质量和气候的了解有限-这将在本项目中解决。目的和目标本项目将使用卫星测量结合新的和现有的多模型模拟来量化土地利用变化对空气质量和气候的关键过程和影响。我们的目标是：研究主要森林砍伐地区的排放和大气组成；评估土地利用变化对空气质量影响的多模式模拟，并用更详细的过程表示改进模型模拟；以及量化未来土地利用、气候和人为排放的变化将如何进一步影响空气质量和气候。

Background and MotivationFuture pressures driven by food security and population growth result in anthropogenic land use change. Land use change impacts air quality by changing natural emissions both of gaseous and aerosol species, and impacts climate through radiative forcing. This occurs because land-use change alters atmosphere-biosphere interactions that influence radiation, moisture and carbon budgets. Vegetation also emits biogenic volatile organic compounds (BVOCs) that form secondary organic aerosols (SOA) that modify levels of major air pollutants particulate matter (PM2.5) and ozone and influence the abundance short-lived climate forcers (SLCFs). In addition, land use change is often brought about by fires and biomass burning that too cause poor air quality and impact climate. Understanding how current and future land-use change, such as large-scale deforestation, impacts atmospheric composition and radiation is important for global efforts to tackle poor air quality and mitigate climate change. A key uncertainty is our limited understanding of how land-use change influences air quality and climate through changes in BVOC emissions and SOA formation -this will be addressed in this project.Aim and ObjectivesThis project will use satellite measurements combined with new and existing multi-model simulations to quantify the key processes and impacts of land use change on air quality and on climate. Our objectives are: to study emissions and atmospheric composition over major areas of deforestation; to assess multi-model simulations of land-use change impacts on air quality and improvements in model simulations with more detailed process representation; and to quantify how the combination of future changes in land use, climate and anthropogenic emissions will further impact air quality and climate.