# API Reference¶

For convenience, we provide here for reference an automatically generated overview of gcpy’s core features and API. We encourage users to learn more about these features by exploring the examples and tutorials provided on this site.

## Top-level functions¶

 open_dataset(filename, **kwargs) Load and decode a dataset from an output file generated by GEOS-Chem open_mfdataset(filenames[, concat_dim, …]) Load and decode multiple GEOS-Chem output files as a single Dataset.

## Atmospheric Sciences¶

General methods and tools for work in the atmospheric sciences.

### Thermodynamics¶

Thermodynamics and equation of state calculations

 airdens(pressure[, temperature]) Compute air mass density for a given temperature and pressure. e_h2o(temperature[, ice_ref, minval]) Calculate water vapor pressure for a given temperature. ussa_alt(pressure) Compute altitude in km for a given pressure corresponding to the US ussa_temp(altitude) Compute reference temperature for a given altitude corresponding to the US Standard Atmosphere.

## Grids¶

Routines for working with GEOS-Chem Classic (rectilinear) and High Performance (cubed-sphere) grids.

## Observations¶

Helper functions for working in conjunction with common observational datasets.

## Plotting¶

Convenience plotting tools and wrappers.

## Units¶

Utility for working with common unit conversions.lr b