Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD), 1998-2021, V5.GL.03

The Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD), 1998-2021, V5.GL.03 consists of annual concentrations (micrograms per cubic meter) of all composition ground-level fine particulate matter (PM2.5). This data set combines AOD retrievals from multiple satellite algorithms including the NASA MODerate resolution Imaging Spectroradiometer Collection 6.1 (MODIS C6.1), Multi-angle Imaging SpectroRadiometer Version 23 (MISRv23), MODIS Multi-Angle Implementation of Atmospheric Correction Collection 6 (MAIAC C6), and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) Deep Blue Version 4. The GEOS-Chem chemical transport model is used to relate this total column measure of aerosol to near-surface PM2.5 concentration. Geographically Weighted Regression (GWR) is used with global ground-based measurements from government agencies, literature-based observations, the World Health Organization Global Ambient Air Quality Database, and OpenAQ to predict and adjust for the residual PM2.5 bias per grid cell in the initial satellite-derived values. These estimates are primarily intended to aid in large-scale studies. Gridded data sets are provided at a resolution of 0.01 degrees to allow users to agglomerate data as best meets their particular needs. Data sets are gridded at the finest resolution of the information sources that were incorporated, but do not fully resolve PM2.5 gradients at the gridded resolution due to influence by information sources at coarser resolution. The data are distributed as GeoTIFF and netCDF formats and are in WGS84 projection.1998-2021年V5.GL.03版MODIS、MISR与SeaWiFS气溶胶光学厚度(Aerosol Optical Depth, AOD)全球年度PM2.5格点数据集，包含所有组分的近地面细颗粒物（PM2.5）年度浓度（单位：微克/立方米）。本数据集整合了多卫星算法反演得到的AOD数据，涵盖美国国家航空航天局(NASA)中分辨率成像光谱仪Collection 6.1版本（MODIS C6.1）、多角度成像光谱辐射计Version 23版本（MISRv23）、MODIS大气校正多角度实现方案Collection 6版本（MAIAC C6）以及海洋宽视场传感器（SeaWiFS）深蓝算法Version 4版本的反演结果。本研究采用GEOS-Chem化学传输模型，将气溶胶整柱含量的观测值关联至近地面PM2.5浓度；同时结合政府机构的全球地面观测数据、文献报道的观测结果、世界卫生组织全球空气质量数据库以及OpenAQ平台数据，通过地理加权回归(Geographically Weighted Regression, GWR)对初始卫星反演得到的各格点剩余PM2.5偏差进行预测与校正。该数据集主要用于支撑大规模相关研究。数据集采用0.01度的格点分辨率，以便用户根据自身研究需求灵活聚合数据。本数据集以纳入的所有数据源中的最高分辨率进行格点化，但由于受较低分辨率数据源的影响，无法完全在当前格点分辨率下解析PM2.5的浓度梯度。数据集以GeoTIFF与netCDF格式分发，投影坐标系为WGS84。