Space-based observations offer a unique opportunity to investigate the atmosphere and its changes over decadal time scales, particularly in regions lacking in situ and/or ground based observations. In this study, we investigate temporal and spatial variability of atmospheric particulate matter (aerosol) over the urban area of Córdoba (central Argentina) using over ten years (2003–2015) of high-resolution (1 km) satellite-based retrievals of aerosol optical depth (AOD). This fine resolution is achieved exploiting the capabilities of a recently developed inversion algorithm (Multiangle implementation of atmospheric correction, MAIAC) applied to the MODIS sensor datasets of the NASA-Terra and -Aqua platforms. Results of this investigation show a clear seasonality of AOD over the investigated area. This is found to be shaped by an intricate superposition of aerosol sources, acting over different spatial scales and affecting the region with different yearly cycles. During late winter and spring (August-October), local as well as near- and long-range transported biomass burning (BB) aerosols enhance the Córdoba aerosol load, and AOD levels reach their maximum values (>0.35 at 0.47 µm). The fine AOD spatial resolution allowed to disclose that, in this period, AOD maxima are found in the rural/agricultural area around the city, reaching up to the city boundaries pinpointing that fires of local and near-range origin play a major role in the AOD enhancement. A reverse spatial AOD gradient is found from December to March, the urban area showing AODs 40–80% higher than in the city surroundings. In fact, during summer, the columnar aerosol load over the Córdoba region is dominated by local (urban and industrial) sources, likely coupled to secondary processes driven by enhanced radiation and mixing effects within a deeper planetary boundary layer (PBL). With the support of modelled AOD data from the Modern-Era Retrospective Analysis for Research and Application (MERRA), we further investigated into the chemical nature of AOD. The results suggest that mineral dust is also an important aerosol component in Córdoba, with maximum impact from November to February. The use of a long-term dataset finally allowed a preliminary assessment of AOD trends over the Córdoba region. For those months in which local sources and secondary processes were found to dominate the AOD (December to March), we found a positive AOD trend in the Córdoba outskirts, mainly in the areas with maximum urbanization/population growth over the investigated decade. Conversely, a negative AOD trend (up to −0.1 per decade) is observed all over the rural area of Córdoba during the BB season, this being attributed to a decrease of fires both at the local and the continental scale.

天基观测提供了一个独特的机会来研究大气及其在十年时间尺度上的变化，特别是在缺乏实地和/或地面观测的地区。在这项研究中，我们利用十年（2003-2015）基于卫星的高分辨率（1公里）气溶胶反演研究了科尔多瓦（阿根廷中部）城区大气颗粒物（气溶胶）的时间和空间变化。光学深度（AOD）。这种精细分辨率是利用最近开发的反演算法（大气校正的多角度实现，MAIAC）的功能实现的，该算法应用于 NASA-Terra 和 -Aqua 平台的 MODIS 传感器数据集。本次调查结果表明，调查区域的 AOD 具有明显的季节性。人们发现，这是由气溶胶源的复杂叠加形成的，作用于不同的空间尺度，并以不同的年周期影响该地区。在冬末和春季（8 月至 10 月），本地以及近程和远程输送的生物质燃烧 (BB) 气溶胶增强了科尔多瓦气溶胶负荷，AOD 水平达到最大值（0.47 µm 处 >0.35）。精细的 AOD 空间分辨率揭示了这一时期，AOD 最大值出现在城市周围的农村/农业地区，一直延伸到城市边界，这表明局部和近距离火灾在火灾中发挥了重要作用。 AOD增强。12月至3月存在反向空间AOD梯度，城区AOD比城市周边地区高40%~80%。事实上，在夏季，科尔多瓦地区的柱状气溶胶负荷主要由当地（城市和工业）来源主导，可能与更深的行星边界层（PBL）内增强的辐射和混合效应驱动的二次过程相耦合。在现代研究与应用回顾分析 (MERRA) 的 AOD 模型数据的支持下，我们进一步研究了 AOD 的化学性质。结果表明，矿物尘也是科尔多瓦的重要气溶胶成分，十一月至二月影响最大。长期数据集的使用最终可以对科尔多瓦地区的 AOD 趋势进行初步评估。在发现当地来源和二次过程主导 AOD 的那些月份（12 月至 3 月），我们发现科尔多瓦郊区出现积极的 AOD 趋势，主要是在调查的十年中城市化/人口增长最大的地区。相反，在 BB 季节期间，科尔多瓦整个农村地区都观察到 AOD 呈负趋势（每十年高达 -0.1），这归因于当地和大陆范围内火灾的减少。