Module Overview

The weather package is organised into focused, single-responsibility modules. Each step of the pipeline is a separate file that can be imported and used independently.

File	Purpose	Key function(s)
`config.py`	Centralised configuration from environment variables (`COSMO_*`). Attribute definitions, URL builders, path resolution.	`get_config()`, `ATTRIBUTES`
`download.py`	Fetch `.grb.bz2` files from DWD OpenData via HTTPS (with resume) or FTP fallback. Skips already-downloaded files.	`download_all()`, `download_attribute_month()`
`decompress.py`	Parallel bz2 decompression using `lbzip2`, `pbzip2`, or Python `bz2` fallback. Atomic writes prevent half-written files.	`decompress_all()`, `decompress_file()`
`transform.py`	Read GRIB with xarray + cfgrib, convert units (K → °C), compute derived fields (GHI, DHI, WS_10M). Chunked via dask (threaded scheduler).	`build_annual_dataset()`, `open_grib_month()`
`export.py`	Write a compressed NetCDF-4 file with zlib encoding. Sequential per-variable compute to limit memory.	`export_netcdf()`
`pipeline.py`	End-to-end orchestrator chaining all four steps. Optional cleanup of intermediate files.	`run_pipeline()`, `validate_environment()`
`from_csv.py`	Load pre-extracted single-point CSV weather files (T, GHI, DNI, DHI). Reconstructs physically-consistent DNI via pvlib DISC decomposition.	`CsvWeatherData`
`__main__.py`	Standalone CLI entry point (`python -m buem.weather`). Mirrors the `buem weather` CLI for server use.	`main()`
`__init__.py`	Package docstring and public API surface.

Standalone Usage

The weather package does not depend on the rest of BuEM. It can run on a remote server where only the src/buem/weather/ directory and src/buem/__init__.py are present:

# Copy to server
scp -r src/buem ssahoo@server:~/buem/src/buem/

# Run directly (no pip install needed — PYTHONPATH only)
export PYTHONPATH=~/buem/src
python -m buem.weather info
python -m buem.weather run --months 1

When installed via pip install -e ., the same functionality is available through the unified CLI:

buem weather info
buem weather run --months 1