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Command Reference

This page groups the executables listed in src/Makefile. It is a user-level summary rather than a full API description.

AIRS Radiance And Footprint Tools

  • spec2tab: extract radiance spectra from a Level-1B granule. Usage: <airs_l1b_file> [index <track> <xtrack> | geo <lon> <lat>] <spec.tab>.
  • spec_qual: extract quality flags for one AIRS footprint. Usage: <airs_l1b_file> <track> <xtrack> <qual.tab>.
  • map_rad: extract radiance maps from one or two Level-1B granules. Usage: <ctl> <l1b_file1> <l1b_file2> <nu> <wave.tab>.
  • orbit: extract AIRS/Aqua orbit information. Usage: <orbit.tab> <airs_l1b_file> [<airs_l1b_file2> ...].
  • optimize_btd: optimize brightness-temperature differences.
  • volcano: detect volcanic ash and sulfur dioxide from Level-1B radiances. Usage: <out.tab> <l1b_file1> [<l1b_file2> ...].

Perturbation, Noise, And Wave Analysis

  • perturbation: create perturbation NetCDF products from Level-1B granules. Usage: <out.nc> <l1b_file1> [<l1b_file2> ...].
  • map_pert: extract perturbation maps. Usage: <ctl> <pert.nc> <map.tab>.
  • noise_pert: estimate noise from perturbation products. Usage: <ctl> <pert.nc> <noise.tab>.
  • variance: calculate brightness-temperature variances. Usage: <ctl> <var.tab> <pert1.nc> [<pert2.nc> ...].
  • events: identify gravity-wave events. Usage: <ctl> <events.tab> <pert1.nc> [<pert2.nc> ...].
  • spec_ana: run spectral analysis of gravity-wave perturbations. Usage: <ctl> <pert.nc> <spec.tab>.
  • spec_synth: run the same spectral analysis workflow on synthetic data. Usage: <ctl> <spec.tab>.
  • sampling: estimate AIRS sampling patterns. Usage: <ctl> <pert.nc>.
  • var1d: estimate horizontal wavelength sensitivity. Usage: <width> <n> <lxmin> <lxmax> <dlx> <fwhm> <dim>.
  • rayt: run the 2-D gravity-wave ray-tracing tool.

Retrieval Preparation And Post-Processing

  • extract: extract radiance data for retrieval inputs. Usage: <airs_l1_file> <airs_l2_file> <out.nc>.
  • retrieval: AIRS retrieval processor. Usage: <ctl> <filelist>.
  • nlte: retrieve non-LTE index. Usage: <ctl> <filelist>.
  • ret2tab: write retrieval data to ASCII. Usage: <airs_l2_file> <layer> <airs.tab>.
  • map_ret: extract retrieval maps. Usage: <ctl> <airs.nc> <map.tab>.
  • noise_ret: estimate noise from retrieval data. Usage: <ctl> <airs.nc> <noise.tab>.
  • diff_apr: compare retrieval and a priori data. Usage: <ctl> <airs.nc> <airs2.nc> <diff.tab>.
  • diff_ret: compare retrieval outputs. Usage: <ctl> <airs.nc> <airs2.nc> <diff.tab>.
  • select_ret: find retrieval results for a geographic selection. Usage: <ctl> [<airs1.nc> <airs2.nc> ...].
  • zm_ret: calculate zonal means for retrieval data. Usage: <ctl> <zm.tab> <airs1.nc> [<airs2.nc> ...].

Case-Specific Analysis Programs

  • hurricane: analyze gravity-wave data for tropical cyclones.
  • island: analyze gravity-wave data for remote islands.
  • overpass: find AIRS/Aqua overpasses for a target location. Usage: <ctl> <pert.nc> <lon0> <lat0> <overpass.tab>.
  • issifm: simulate AIRS observations from atmospheric model output.

Utility Programs

  • day2doy: convert calendar date to day-of-year.
  • doy2day: convert day-of-year to calendar date.
  • time2jsec: convert date and time to Julian seconds.
  • jsec2time: convert Julian seconds to date and time.
  • distance: calculate distance between two geolocations.
  • sza: calculate solar zenith angle.

Shared Libraries

  • libairs.c and libairs.h: AIRS-specific data structures and helper routines.
  • jurassic.c and jurassic.h: retrieval framework used by retrieval and nlte.

For implementation-level details, use the Doxygen output linked on the Links page.