Aerosol particles over the Bay of Bengal – characteristic, variability and sources – a comprehensive measurement and analysis approach during the BIOCAT-IIOE2 (Aerosol-BIOCAT)

气溶胶粒子是重要的气候驱动力，因为它们散射和吸收太阳辐射，并影响云的形成和特征。为了更好地了解气溶胶颗粒的各种气候影响，需要对气溶胶的来源和处理有一个适当的了解，这在很大程度上仍然是未知的。迄今为止，关于气溶胶化学性质在时间和空间分辨率方面的可变性以及关于其混合状态的信息很少。一般情况下，海洋，特别是印度洋北部上空气溶胶颗粒的大陆排放和人为排放强度知之甚少，量化也很差，这给估计海洋气溶胶的气候影响造成了很大的不确定性。在气溶胶-BIOCAT项目中，我们的目标是通过应用详细的现场测量和统计分析，填补在孟加拉湾(BOB)上空气溶胶颗粒的可变性、来源和环境驱动因素方面存在的巨大知识空白。我们将与R/V SONE(SO305/BIOCAT)一起参加BIOCAT-IIOE2研究巡航，并与气溶胶-BIOCAT一起执行这次巡航中的主要大气研究部分。为此，我们将综合使用与气溶胶和海洋表面微层(SML)的综合化学特征相关的在线气溶胶物理化学测量。将获得一个独特的气溶胶特征数据集，并将对该数据集进行先进的接收器模型，从而能够对BOB的两个横断面(南-北和北-南)东北季风期间不同的气溶胶来源进行定量归属。具有高时间分辨率的物理测量将允许观察气溶胶动力学(例如，新粒子的形成)或气溶胶类型之间的转变。对海水的化学分析，特别是对SML的化学分析，将首次提供一个数据集，为有机物质从海洋向大气的转移、BOB地区黑碳向海洋表面的沉积以及SML对冰核粒子(INP)的作用提供新的见解。这些调查将使人们能够适当了解海洋来源，并为TROPOS现有的增强型SML数据集增加有价值的信息。总体而言，在本项目范围内，将获得关于东北季风期间海洋和非海洋来源的新的定量信息，以及大气气溶胶粒子在BOB中的进一步处理。研究结果将有助于缩小对受污染海洋区域的自然(海洋、粉尘)和人为来源重要性的认识差距。预期的结果将对更好地模拟海洋上的粒子传输和改善对其气候影响的预测具有极其重要的价值。

Aerosol particles are important climate drivers as they scatter and absorb solar radiation and impact the formation and characteristics of clouds. To better understand the diverse climatic effects of aerosol particles, a proper understanding of the aerosol sources and processing is required that is to date still largely missing. Few information on the variability of aerosol chemical properties regarding their temporal and spatial resolution as well as information on their mixing state exist to date. The strength of continental and anthropogenic emissions on the aerosol particles over the ocean in general, and over northern part of the Indian Ocean in particular, is little understood and poorly-quantified, causing strong uncertainties in the estimation of the climate effect of marine aerosols. Within the project Aerosol-BIOCAT we aim to fill the big gaps of knowledge that exist concerning the variability, sources, and environmental drivers on the aerosol particles over the Bay of Bengal (BoB) by applying elaborated field measurements and statistical analysis. We will participate in the BIOCAT-IIOE2 research cruise with R/V Sonne (SO305/BIOCAT) and with Aerosol-BIOCAT we will perform the main atmospheric research component in this cruise. To this end, we will use a combination of online aerosol physico-chemical measurements associated to a comprehensive chemical characterization of the aerosols and the marine sea surface microlayer (SML). A unique data set of aerosol characteristics will be obtained, and advance receptor models will be performed on the dataset allowing a quantitative attribution of different aerosol sources during the North-East monsoon over two transects of the BoB (South-North and North-South). The physical measurements with the high temporal resolution will allow to observe aerosol dynamics (e.g. the formation of new particles) or transitions between aerosol types. The chemical analysis of seawater and especially of the SML will deliver a first-time dataset that will provide new insights into the transfer of organic matter from the ocean to the atmosphere as well as the deposition of black carbon to the ocean surface in the BoB region and the role of SML on Ice nucleating particles (INP). These investigations will allow a proper understanding of marine sources and add valuable information to the enhanced SML dataset existent at TROPOS. Overall, within the presented project new, quantitative information about the marine and non-marine origin and further processing of atmospheric aerosol particles in the BoB during the North-East monsoon will be obtained. The results will help to reduce the gaps of knowledge regarding the importance of natural (oceanic, dust) and anthropogenic sources in polluted marine regions. The expected results will be extremely valuable for better modeling particle transport over the ocean and improve the prediction on their climate effects.