CrIS Code Collection
CrIS Code Collection

The CrIS Code Collection is a C-based toolkit for processing and analyzing remote sensing observations from the Cross-track Infrared Sounder (CrIS) instruments.

This Doxygen manual is the API-oriented reference for the CrIS source tree. It documents the shared data structures, helper routines, and file-level interfaces used by the command-line tools in src/.

Overview

The documented codebase includes routines for:

  • reading CrIS Level-1B radiance granules
  • representing radiance, perturbation, retrieval, and wave-analysis data
  • extracting spectra and geolocated radiance maps
  • generating perturbation products in netCDF format
  • estimating perturbation noise and local variance
  • deriving volcanic ash and SO2 indicator tables

Getting Started

The main CrIS-specific declarations are defined in libcris.h, with the corresponding implementations in libcris.c.

Useful entry points in this manual are:

  • libcris.h for shared structs, macros, and function declarations
  • cris_l1_t for the in-memory representation of CrIS Level-1 data
  • pert_t for perturbation products
  • retr_t for retrieval output tables
  • wave_t for wave-analysis grids and derived fields

Functional Areas

Core I/O routines include read_cris_l1 for Level-1B radiance granules and read_pert for perturbation products.

Shared numerical routines include background_poly, background_smooth, create_wave, fft, noise_pert, and variance.

The executable programs in src/ build on these shared routines. The most prominent tools are spec2tab, map_rad, perturbation, map_pert, noise_pert, variance, and volcano.

Repository Layout

  • src/: C sources, headers, and executable programs
  • tests/: regression tests and reference outputs
  • docs/: MkDocs and Doxygen sources
  • libs/: bundled third-party library sources and local build helper

Related Documentation

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