SWAAMI (South West Asian Aerosol Monsoon Interactions)

来自印度次大陆污染源的气溶胶颗粒在印度和孟加拉湾形成了密集而广泛的烟雾，在季风到来之前，烟雾的范围和强度都有所增加。由于气溶胶，其中很大一部分来自木材和木炭燃烧的炉灶，吸收太阳辐射以及散射它，它们可以影响低层大气的热平衡。据推测，这种气溶胶可以通过其在季风前的整个区域的热量重新分配的作用来影响季风，模型研究表明，这种影响可能是重要的。然而，目前的比较显示，模型模型的变异性和预测不足相比，观测，一个强有力的迹象表明，详细的气溶胶特性是在目前的模式代表性差。在这些模型中，缺乏准确的气溶胶表示，由于缺乏足够的精度和灵敏度的测量来阐明基本特性，如组分质量，混合状态和光学特性，需要很好地表征，以提高模型性能。这限制了目前的预测能力，因此阻止了印度季风气溶胶的影响被量化。除了再现气溶胶的详细特性外，模型还需要能够准确地表示不同气溶胶的水平和垂直分布，以预测其影响。随着季风的发展，污染气溶胶被降水带走，但也被对流带走。沙尘平流从沙漠到西部以上的潮湿季风流成为显着的整个季节。重要的是，这些气溶胶层在模型中得到准确的表示，并提供可靠的测量，以严格挑战模型的预测，SWAAMI将通过使用英国和印度的研究飞机详细确定印度季风之前和期间印度各地气溶胶的物理和化学特性，为NERC-MoES联合方案“亚洲季风的可变性驱动因素”作出贡献。这些测量将提供比以往任何测量都详细得多的气溶胶的化学和物理特性，并将能够评估气溶胶的组成和混合状态，提供源特性，并提供气溶胶光学特性的量化，如消光、吸收和单次散射。这种详细的表征将使我们能够在区域和全球气候模式中测试气溶胶特性的表示。我们计划的飞机测量将与来自整个大陆的长期数据和以前的实地研究的综合相结合，以提供一个数据集，可以挑战模型在该地区代表气溶胶的能力。改进模型表示的气溶胶属性和测试的程度，这提高了模型的性能对数据将提供一个框架，以确保模型气溶胶方案改善，这样做将使我们能够更可靠的预测气溶胶对该地区的热收支的影响，从而提高我们的知识气溶胶如何可能影响印度季风。

Aerosol particles from pollution sources across the Indian subcontinent form a dense and extensive haze across India and the Bay of Bengal that increases in extent and magnitude in advance of the monsoon. As the aerosols, a large fraction of which arises from wood and charcoal fired cookstoves, absorb solar radiation as well as scatter it they can affect the heat balance of the lower atmosphere. It has been hypothesised that this aerosol can influence the monsoon through its role in redistribution of heat across the region in the pre-monsoon, and model studies have demonstrated that such effects can be important. However, current comparisons show model to model variability and under-prediction compared to observations, a strong indication that detailed aerosol properties are poorly represented in current models. The lack of accurate representation of aerosol in these models is compounded by a lack of measurements of sufficient accuracy and sensitivity to elucidate fundamental properties such as component mass, mixing state and optical properties, which need to be well characterised to improve model performance. This is limiting predictive capability at the present time and hence preventing the influence of aerosol in the Indian monsoon to be quantified. In addition to reproducing detailed properties of aerosol, models need to be able to accurately represent the horizontal and vertical distribution of different aerosols to predict their effects. As the monsoon progresses, pollution aerosol are removed by precipitation, but also lofted by convection. Dust advected from deserts to the west above the moist monsoonal flow become significant through the season. It is important that these aerosol layers are accurately represented in models and that robust measurements are available to rigorously challenge model predictions.SWAAMI will contribute to the joint NERC-MoES programme "Drivers of Variability in the Asian Monsoon" through a detailed determination of aerosol physical and chemical properties across India in the advance of, and during, the Indian monsoon using UK and Indian research aircraft. The measurements will deliver a chemical and physical characterisation of the aerosol that is considerably more detailed than any previous and will enable assessment of aerosol composition and mixing state, provide source characterisation and deliver quantification of aerosol optical properties such as extinction, absorption and single scattering albedo. Such detailed characterisation will allow us to test representations of aerosol properties in regional and global climate models. Our planned aircraft measurements will be combined with syntheses of long term data from across the continent and previous field studies to provide a data set that can challenge how well models represent aerosol across the region. Improving model representations of aerosol properties and testing the extent to which this improves model performance against data will provide a framework for ensuring model aerosol schemes improve and in doing so will allow us to make more reliable predictions of aerosols effects on the heat budget of the region and hence improve our knowledge of how aerosols may influence the Indian monsoon.