MERRA2AODANAProcessor ===================== Overview -------- The `MERRA2AODANAProcessor` module is designed to extract and convert aerosol optical depth data (`AODANA`) from NASA’s MERRA-2 atmospheric reanalysis dataset. Specifically, it focuses on transforming `.nc4` files (NetCDF format) into structured `.csv` outputs for downstream dust storm fusion analysis and visualization. Unlike `DUSMASS`, which measures surface-level dust mass concentration, `AODANA` represents the **total column aerosol optical depth**—a key variable for estimating aerosol load in the atmosphere. Including this variable provides a second dimension to storm confidence assessments, especially in dusty but optically active regions. Functionality ------------- This module performs the following tasks: - Iterates through a directory of `.nc4` files containing daily MERRA-2 `AODANA` data. - Extracts metadata such as: - Time (hourly UTC timestamps) - Latitude and longitude grid - `AODANA` values for each grid point - Filters out invalid or missing values (e.g., fill values) - Writes the processed data into `.csv` files, one per day, preserving temporal and spatial resolution. Scientific Motivation --------------------- `AODANA` is a critical metric in remote sensing and atmospheric science as it: - Provides insight into how optically thick the atmosphere is due to aerosols - Helps distinguish between fine particulate pollution, sea salt, and dust - Complements `DUSMASS` by adding a **vertical optical measurement** over surface-based mass estimation This dual perspective is particularly useful when fusing datasets in modules like `FusionStormDetector`, which require strong evidence from both mass and optical profiles to confirm a dust storm. Integration with Other Modules ------------------------------ - Used in conjunction with `MERRA2DUSMASSProcessor` for fusion-based blob detection in `FusionStormDetector`. - May also be compared with satellite instruments or METARs for cross-validation. - CSVs generated here are expected in the same format as DUSMASS files to allow seamless pairing and temporal matching. File Structure -------------- Each generated `.csv` file contains the following fields: - `latitude`: Grid latitude in degrees - `longitude`: Grid longitude in degrees - `datetime`: UTC time (with hourly resolution) - `AODANA`: Aerosol Optical Depth at 550 nm The filename format is standardized as:YYYYMMDD.csv where `YYYYMMDD` corresponds to the date of the original `.nc4` file. Usage Considerations -------------------- - This processor assumes a consistent grid and variable name (`AODANA`) in the MERRA-2 files. - Missing data (e.g., due to quality filtering or oceanic regions) are excluded from the CSV output. - The output folder is automatically created if it doesn't exist. Dependencies ------------ - `netCDF4` - `pandas` - `numpy` - `os` and `glob` for file handling - `tqdm` for progress bars Author ------ Developed by Muhammad Aqeel Abdulla as part of the Dusty pipeline for enhanced storm tracking and verification.