Ask the virtual scientist
Application Program Interface (API)
PSG allows to perform operations remotely by employing a versatile online Application Program Interface (API). The API operates by sending a configuration file to the PSG servers, that can modified on the local machine as needed. Upon reception of the configuration file, PSG will compute the spectra and send back the planetary spectra. The great value of the API is that the user does not need to install / update the radiative transfer modules and databases on his/her computer, and by simply performing a 'curl' command, the user will run the simulations on high-performance NASA servers.
The configuration file is a relaxed form of XML (eXtensible Markup Language), the now preferred file type across applications. The spectra is provided in standard ASCII columns. The resulting units for the columns can be defined with the configuration XML file, while which type of data to provide (e.g., radiance, transmittance, noise) is provided by a POST command.
The communication with the server is performed via HTTPS, and this can be implemented via the 'curl' terminal command. A single line of 'curl', in which the user inputs are provided via a psg_cfg.txt (example) will lead to spectra. The figure below better explains the inner workings of the PSG modules, and how the user can enable / disable the different modules, and request for different spectral outputs.
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| Application Program Interface: PSG can be called from a local machine via the 'curl' command that employs the HTTP protocol for establishing the communication between the local machine and the PSG servers. The user sends a XML configuration file, and receives different type of spectral results (str, tel, srf, trn, atm, rad, noi), all standarized as text ASCII tables. The API will call the required modules (geometry, atmosphere, continuum, pumas/cem, generator) in a sequencial order, yet the user can also enable / disable modules as needed. Examples are presented in the next section. |
Calling the API
In order to compute spectra, one first needs to create / modify a PSG configuration file. The user can choose to edit this file with any text editor or scripting language.
1) Obtain a template configuration file (e.g., psg_cfg.txt). The easiest way to obtain a configuration file is by parameterizing PSG via the web interface until a desired spectrum is obtained. On the main page of PSG, then click on "Download config-file", this will download the XML configuration file. A generic template can be also downloaded here.
2) Modify the psg_cfg.txt configuration file using a text-editor, or using any scripting / programming language. In order to better understand what each parameter means, please refer to the PSG documentation.
3) Open a terminal window and type the following command:
curl --data-urlencode file@psg_cfg.txt https://psg.gsfc.nasa.gov/api.php
4) By default, the API will run all PSG modules employing this configuration file, and will return the total radiance spectra (rad file). As shown in the figure above, one can run only certain modules and request for a different type of spectral output. This is achieved by providing several POST keywords (see table below). For instance:
To return planetary transmittances without the header information:
curl -d type=trn -d whdr=n --data-urlencode file@psg_cfg.txt https://psg.gsfc.nasa.gov/api.php
To return only stellar transmittances (the API will only run the module 'continuum'):
curl -d type=str --data-urlencode file@psg_cfg.txt https://psg.gsfc.nasa.gov/api.php
5) With the API, the user can also compute ephmerides and/or atmospheric parameters. For instance:
a) Create a text file psg_cfg.txt with this content:
<OBJECT-DATE>2017/01/15 14:30
<OBJECT-NAME>Mars
<GEOMETRY-REF>MRO[74]
b) Call the API with this command:
curl -d type=cfg -d wephm=y -d watm=y --data-urlencode file@psg_cfg.txt https://psg.gsfc.nasa.gov/api.php
Installing a personal version of PSG on your computer
The user can install and run a local version of PSG via a virtualization system. PSG is a complex suite of spectroscopic models and databases, coordinated by a general radiative-transfer scheme. Installing the whole suite on a personal system can be a daunting process and would entail a great deal of resources / memory / time. By employing a container virtualization system, the user can easily install a pre-configured Virtual Machine with PSG that provides web/API access as the normal PSG suite.
Fully free: PSG is installable employing the no-cost Docker Engine, which is an open source containerization technology for building and virtualizing applications. Docker engine is fully free and licensed under the open-source Apache license. To enable the Docker Engine on your machine, you can use the also free Rancher Desktop application, which is open-source and licensed under the public Apache license. Alternatively, Docker Desktop is free for personal use, yet users from large organizations (including government) require a paid license. We encourage users to employ the free and open-source Rancher Desktop and Docker Engine configuration when possible.
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PSG can be installed in any personal computer (Mac, Linux or Windows based) via the Docker Engine. Docker containers wrap up software and all its dependencies (including the operative system) into a standardized package that includes everything it needs to run: code, runtime, system tools and libraries. This guarantees that PSG will always run the same and Docker makes its installation as simple as pulling a container image. This also means that PSG can be easily deployed in cloud computing environments (e.g., Google Cloud, Amazon Web Services). On Linux machines, the Docker Engine can be easily added as a service, since it is native to this operative system, while you can run the Docker Engine on your Mac/Windows machine by installing the fully-free Rancher Desktop application. |
1) Install the free Docker Engine on your machine. If in Linux, this can by simply done by performing a 'yum install docker' in Centos/RHEL or with apt-get on Debian and others (more info):
yum install docker
sudo systemctl start docker
In Macs or in Windows, you would need to install the free Rancher Desktop application on your computer. This is relatively easy and it will establish a virtualization system in which PSG will run. When installing, make sure to select 'dockerd (moby)' for the container runtime, 'Automatic' for path configuration, disable 'Kubernetes'. To avoid requiring 'sudo access' or administrative access to the app, please consider installing in your home applications directory not (/Applications). The application is downloadable at rancherdesktop.io.
2) From the command line / terminal, enter the following commands to pull the PSG container from the publicly available Docker hub repository:
For computers with Apple M1/M2 ARM chips
docker logout
docker pull nasapsg/psg
docker tag nasapsg/psg psg
For all other computers
docker logout
docker pull nasapsg/psg-amd
docker tag nasapsg/psg-amd psg
3) To run PSG and enable its API interface (add the keyword '--restart always' to keep PSG always running, even after re-booting):
docker run -d --name psg -p 127.0.0.1:3000:80 psg
4) To visit the local site of PSG, open your browser and go to http://localhost:3000, while to run the local version of the Application-Program-Interface (API), enter the following command:
curl --data-urlencode file@psg_cfg.txt http://localhost:3000/api.php
5) The user can install, upgrade and remove packages by visiting http://localhost:3000. For performing this from the command line (e.g., inside a VM instance) follow these commands (where 'package' is the package name, all in lower case):
curl http://localhost:3000/index.php?install=package
curl http://localhost:3000/index.php?update=package
curl http://localhost:3000/index.php?remove=package
Some useful docker commands are (full list here):
| docker stop psg | Stops the current PSG container. |
| docker restart psg | Restarts the PSG service. |
| docker start psg | Starts the PSG service if stopped. |
| docker rm psg | Removes the current container of PSG from docker memory. This operation deletes all updates/installed packages since its initial run, and resets PSG. |
| docker ps -a | Lists the status (e.g., stopped, started, exited) of all currently available containers. Containers cannot be re-run if they have already been created and therefore appear in this list (independently of the status). Restart if necessary, while if the user wants to reset PSG to its original image, remove the container (docker rm) and re-run it (docker run). |
| docker image ls | Lists all the available docker images. The user can spawn multiple instances/containers from the same image. When the user pulls the PSG image from the docker hub, then this image will appear in this list. |
| docker image rm psg | Deletes the PSG image from memory. Any new PSG container/instance will require a re-pull of the image from the docker hub. |
| docker system prune -af | Deletes all images and containers/instances from docker memory, fully resetting docker. |
In order to provide flexibility, the PSG personal suite is organized in packages. By default, the personal suite of PSG comes with the PROGRAMS and BASE packages, yet the user can install many additional packages, expanding the capabilities of the local version. Specifically, the correlated-k tables for low/moderate spectral resolutions can be quite heavy, and should be installed only when strictly necessary. The local PSG site also keeps track of any updates of these packages with respect to the current PSG suite, and it will inform you if you are required to update the packages.
| Available packages for PSG Personal Suite |
 Package programsSize: 0.8 MB (uncompressed 1.6 MB) Latest version: 2024-04-23 Operational software and programs required by PSG for Apple M1/M2 chips computers. This package includes all the necessary binaries to perform the radiative transfer calculations and retrievals, together with the PHP server interpreter modules. This package cannot be removed (it is fundamental for the operation of PSG), and it should be constantly updated to reflect the upgrades performed to the suite. |
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Package programsamd Size: 0.8 MB (uncompressed 1.6 MB) Latest version: 2024-04-23 Operational software and programs required by PSG for Linux/Windows AMD chips computers. This package includes all the necessary binaries to perform the radiative transfer calculations and retrievals, together with the PHP server interpreter modules. This package cannot be removed (it is fundamental for the operation of PSG), and it should be constantly updated to reflect the upgrades performed to the suite. |
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Package base Size: 0.4 GB (uncompressed 1.8 GB) Latest version: 2024-04-23 This package includes the basic spectroscopic data for performing line-by-line calculations across a broad range of wavelengths and domains. It includes:
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Package surfaces Size: 0.3 GB (uncompressed 1.6 GB) Latest version: 2022-05-22 The surface spectroscopic package includes the complete repository of optical constants and reflectances from all databases handled by PSG (e.g., RELAB, USGS, JENA). |
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Package atmospheres Size: 3.6 GB (uncompressed 8.7 GB) Latest version: 2023-02-28 This package includes the climatological and atmospheric files needed by the 'atmosphere' module. Specifically, it includes:
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Package ephm Size: 0.8 GB (uncompressed 1.1 GB) Latest version: 2022-02-06 The ephemerides package includes orbital and geometric used by the 'geometry' module. Specifically, it includes:
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Package telluric Size: 0.9 GB (uncompressed 2.5 GB) Latest version: 2022-01-09 This package includes the database of telluric transmittances necessary when computing spectra as observed with ground-based observatories. It includes:
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Package xcross Size: 107 MB (uncompressed 446.5 MB) Latest version: 2021-12-10 This package contains hundreds of absorption cross-sections for complex volatiles as reported by the latest HITRAN release. |
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Package lines Size: 0.6 GB (uncompressed 2.5 GB) Latest version: 2022-02-21 This package contains line-by-line spectroscopic information from several databases.
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Package fluor Size: 4.6 GB (uncompressed 6.2 GB) Latest version: 2023-09-13 This package contains non-LTE fluorescence efficiencies for dozens of species, suitable when synthesizing cometary spectra in the UV/optical/IR range. |
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Package exo Size: 0.2 GB (uncompressed 1.1 GB) Latest version: 2021-12-10 This package contains molecular and atomic cross-sections applicable for exoplanetary modeling, and it is based on the database employed by the open source 'Exo-Transmit' code (Kempton et al. 2017). |
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Package grids Size: 4.5 GB (uncompressed 6.8 GB) Latest version: 2022-01-13 When running nested sampling retrievals with PSGnest, the user can choose from a pre-computed set of spectral grids. This packages provides access to the ATMO spectral grid for hot-Jupiters and the terrestrial grid applicable to direct imaging of terrestrial planets. |
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Package corrklowmain Size: 5 GB (uncompressed 8.2 GB) Latest version: 2023-02-06 This package contains correlated-k tables at low-resolution (for simulations with a resolving power lower/equal than 500) for the main molecular species (H2O, CO2, O3, N2O, CO, CH4, O2, SO2, NH3, N2, H2) in all available collisional regimes (e.g., air, CO2, H2, He). |
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Package corrklowtrace Size: 5.2 GB (uncompressed 9.3 GB) Latest version: 2023-02-06 This package contains correlated-k tables at low-resolution (for simulations with a resolving power lower/equal than 500) for trace molecular species (NO2, HCl, OCS, H2CO, HCN, C2H2, C2H6, PH3, H2S) in all available collisional regimes (e.g., air, CO2, H2, He). |
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Package corrklowhot Size: 1 GB (uncompressed 2.5 GB) Latest version: 2023-02-08 This package contains high-energy correlated-k tables at low-resolution computed with HITEMP for (H2O, CO, CH4) in available collisional regimes (e.g., air, CO2, H2, He). |
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Package corrkmedmain Size: 22.3 GB (uncompressed 39.3 GB) Latest version: 2022-09-11 This package contains correlated-k tables at medium-resolution (for simulations with a resolving powers up to 5000) for the main molecular species (H2O, CO2, O3, N2O, CO, CH4, O2, SO2, NH3, N2, H2) in an air collisional regime. |
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Package corrkmedtrace Size: 22.3 GB (uncompressed 35.7 GB) Latest version: 2022-09-11 This package contains correlated-k tables at medium-resolution (for simulations with a resolving powers up to 5000) for trace molecular species (NO2, HCl, OCS, H2CO, HCN, C2H2, C2H6, PH3, H2S, C2H4) in an air collisional regime. |
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Package corrkmedco2 Size: 22.3 GB (uncompressed 32.1 GB) Latest version: 2022-09-11 This package contains correlated-k tables at medium-resolution (for simulations with a resolving powers up to 5000) for all molecular species (H2O, CO2, CO, SO2, NH3, HCl, OCS, H2CO, C2H2) having CO2 collisional lineshape parameters. |
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Package corrkmedh2 Size: 22.3 GB (uncompressed 35.7 GB) Latest version: 2022-09-11 This package contains correlated-k tables at medium-resolution (for simulations with a resolving powers up to 5000) for all molecular species (CO, SO2, NH3, HCl, OCS, H2CO, HCN, C2H2, H2S, H2) having H2 collisional lineshape parameters. |
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Package corrkmedhe Size: 22.3 GB (uncompressed 32.1 GB) Latest version: 2022-09-11 This package contains correlated-k tables at medium-resolution (for simulations with a resolving powers up to 5000) for all molecular species (CO, SO2, NH3, HCl, OCS, H2CO, HCN, C2H2, H2S) having He collisional lineshape parameters. |
Types of planetary spectra and special keywords
| Requested spectra (type keyword) | |
| rad | Integrated fluxes, incorporating all planetary and stellar transmittances, and considering the specific instrument / observatory parameters. This file is computed by the module generator. This is the default output setting. |
| noi | Synthetic observational noise, including the noise introduced by the planet itself, its star (if present within the field), background sources (e.g., exozodii, local zodiacal dust, CMB), the terrestrial atmosphere (if observing from ground), and the instrument performance. This file is computed by the module generator. |
| trn | Integrated planetary transmittance spectra, including all geometry considerations and requested atmospheric parameters. This file is computed by the module PUMAS only. |
| atm | Integrated planetary fluxes as observed at the planet in units of [W m-2 sr-1 um-1]. This file is computed by the modules PUMAS and CEM. |
| str | Stellar transmittance spectrum. This file is computed by the module continuum. |
| tel | Terrestrial transmittance spectrum. This file is computed by the module continuum. |
| srf | Surface reflectance and emissivity spectra. This file is computed by the module continuum. |
| cfg | The API will return the updated configuration file. This file is computed by the modules geometry and atmosphere. |
| all | This keyword will return all the resulting spectra, and the configuration file. |
| Special keywords | |
| wgeo | The geometry module computes the observational angles (GEOMETRY-SOLAR-ANGLE, GEOMETRY-OBS-ANGLE) and the beam/planet ratio (GEOMETRY-PLANET-FRACTION) employing the geometry information provided by the user in the XML configuration file. For exoplanets, it also computes the planet transit factor (GEOMETRY-STAR-FRACTION), and the planet-star distance (GEOMETRY-STAR-DISTANCE). This information is then saved into the configuration file to be used by the other modules. The default is wgeo=y, yet one can disable this computation with wgeo=n. |
| wephm | This keyword enables the calculation of ephemeris parameters based on the object name and the provided date:
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| watm | This keyword enables / disables the atmosphere module - Default watm=n. |
| whdr | This keyword allows to disable outputing the header information - Default whdr=y. |
Full list of parameters accepted by PSG
| Type | Keyword | Range | Description | |
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OBJECT | S50 | Object type (e.g., Exoplanet, Planet, Asteroid, Moon, Comet, Object) | |
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OBJECT-NAME | S50 | Object name | |
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OBJECT-DATE | S20 | Date of the observation (yyyy/mm/dd hh:mm) in Universal time [UT] | |
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OBJECT-DIAMETER | 1e-2 | 1e8 | Diameter of the object [km] |
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OBJECT-GRAVITY | 0 | 1e35 | Gravity/density/mass of the object |
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OBJECT-GRAVITY-UNIT | S10 | Unit for the OBJECT-GRAVITY field, g:'Surface gravity [m/s2]', rho:'Mean density [g/cm3]', or kg:'Total mass [kg]' | |
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OBJECT-STAR-DISTANCE | 0 | 1e5 | Distance of the planet to the Sun [AU], and for exoplanets the semi-major axis [AU] |
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OBJECT-STAR-VELOCITY | -1e4 | 1e4 | Velocity of the planet to the Sun [km/s], and for exoplanets the RV amplitude [km/s] |
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OBJECT-SOLAR-LONGITUDE | -360 | 360 | Sub-solar east longitude [degrees] |
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OBJECT-SOLAR-LATITUDE | -90 | 90 | Sub-solar latitude [degrees] |
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OBJECT-SEASON | 0 | 360 | Angular parameter (season/phase) that defines the position of the planet moving along its Keplerian orbit. For exoplanets, 0:Secondary transit, 180:Primary transit, 90/270:Opposition. For solar-system bodies, 0:'N spring equinox', 90:'N summer solstice', 180:'N autumn equinox', 270:'N winter solstice' [degrees] |
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OBJECT-INCLINATION | 0 | 90 | Orbital inclination [degree], mainly relevant for exoplanets. Zero is phase on, 90 is a transiting orbit |
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OBJECT-POSITION-ANGLE | 0 | 360 | Position angle (counter-clockwise [east] with respect to the direction of the true-of-date reference-frame RA/DEC north-pole) of the planetary North-South axis |
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OBJECT-STAR-TYPE | S1 | Stellar type of the parent star [O/B/A/F/G/K/M] | |
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OBJECT-STAR-TEMPERATURE | 1 | 1e5 | Temperature of the parent star [K] |
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OBJECT-STAR-RADIUS | 1e-3 | 1e8 | Radius of the parent star [Rsun] |
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OBJECT-STAR-METALLICITY | -10.0 | 10.0 | Metallicity of the parent star and object with respect to the Sun in log [dex] |
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OBJECT-OBS-LONGITUDE | -360 | 360 | Sub-observer east longitude [degrees] |
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OBJECT-OBS-LATITUDE | -90 | 90 | Sub-observer latitude, for exoplanets inclination [degrees] |
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OBJECT-OBS-VELOCITY | -1e4 | 1e4 | Relative velocity between the observer and the object [km/s] |
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OBJECT-PERIOD | 0 | 1e8 | This field is computed by the geometry module - It is the apparent rotational period of the object as seen from the observer [days] |
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OBJECT-ORBIT | S100 | This field reports the orbital parameters for small bodies. It is only relevant for display purposes of the orbital diagram. | |
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GEOMETRY | S20 | Type of observing geometry | |
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GEOMETRY-REF | S50 | Reference geometry (e.g., ExoMars, Maunakea), default is user defined or 'User' | |
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GEOMETRY-OFFSET-NS | -1e6 | 1e6 | Vertical offset with respect to the sub-observer location |
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GEOMETRY-OFFSET-EW | -1e6 | 1e6 | Horizontal offset with respect to the sub-observer location |
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GEOMETRY-OFFSET-UNIT | S10 | Unit of the GEOMETRY-OFFSET field, arcsec / arcmin / degree / km / diameter | |
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GEOMETRY-OBS-ALTITUDE | 0 | 1e8 | Distance between the observer and the surface of the planet |
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GEOMETRY-ALTITUDE-UNIT | S10 | Unit of the GEOMETRY-OBS-ALTITUDE field, AU / km / diameter and pc:'parsec' | |
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GEOMETRY-AZIMUTH | 0 | 360 | The azimuth angle between the observational projected vector and the solar vector on the reference plane. |
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GEOMETRY-USER-PARAM | 0 | 1000 | Parameter for the selected geometry, for Nadir / Lookingup this field indicates the zenith angle [degrees], for limb / occultations this field indicates the atmospheric height [km] being sampled |
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GEOMETRY-STELLAR-TYPE | S1 | For stellar occultations, this field indicates the type of the occultation star [O/B/A/F/G/K/M] | |
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GEOMETRY-STELLAR-TEMPERATURE | 1 | 1e5 | For stellar occultations, this field indicates the temperature [K] of the occultation star |
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GEOMETRY-STELLAR-MAGNITUDE | -30 | 30 | For stellar occultations, this field indicates the brightness [magnitude] of the occultation star |
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GEOMETRY-OBS-ANGLE | S1000 | This field is computed by the geometry module - It indicates the angle between the observer and the planetary surface | |
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GEOMETRY-SOLAR-ANGLE | S1000 | This field is computed by the geometry module - It indicates the angle between the Sun and the planetary surface | |
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GEOMETRY-DISK-ANGLES | 1 | 10 | This field allows to divide the observable disk in finite rings so radiative-transfer calculations are performed with higher accuracy |
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GEOMETRY-PLANET-FRACTION | S1000 | This field is computed by the geometry module - It indicates how much the beam fills the planetary area (1:maximum) | |
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GEOMETRY-STAR-FRACTION | 0 | 1 | This field is computed by the geometry module - It indicates how much the beam fills the parent star (1:maximum) |
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GEOMETRY-STAR-DISTANCE | -1 | 1e8 | This field is computed by the geometry module - It indicates the projected distance between the beam and the parent star in arcsceconds |
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GEOMETRY-ROTATION | S15 | This field is computed by the geometry module - It indicates the rotational Doppler shift [km/s] affecting the spectra and the spread of rotational velocities [km/s] within the FOV | |
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GEOMETRY-BRDFSCALER | S1000 | This field is computed by the geometry module - It indicates the scaling factor between the integrated reflectance for the FOV with respect to the BRDF as computed using the geometry indidence/emission angles | |
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ATMOSPHERE-STRUCTURE | S100 | The structure of the atmosphere, None / Equilibrium:'Hydrostatic equilibrium' / Coma:'Cometary expanding coma' | |
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ATMOSPHERE-PRESSURE | 0 | 1e35 | For equilibrium atmospheres, this field defines the surface pressure; while for cometary coma, this field indicates the gas production rate |
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ATMOSPHERE-PUNIT | S20 | The unit of the ATMOSPHERE-PRESSURE field, Pa:Pascal / bar / kbar / mbar / ubar / at / atm / torr / psi / gas:'molecules / second' / gasau:'molecules / second at rh=1AU' | |
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ATMOSPHERE-TEMPERATURE | 1 | 1e4 | For atmospheres without a defined P/T profile, this field indicates the temperature across all altitudes |
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ATMOSPHERE-WEIGHT | 1 | 1e5 | Molecular weight of the atmosphere [g/mol] or expansion velocity [m/s] for expanding atmospheres |
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ATMOSPHERE-CONTINUUM | S300 | Continuum processes to be included in the calculation | |
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ATMOSPHERE-NGAS | 0 | 20 | Number of gases to include in the simulation |
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ATMOSPHERE-GAS | S300 | Name of the gases to include in the simulation, e.g 'H2O, CO2'. Only these will considered for the radiative transfer | |
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ATMOSPHERE-TYPE | S300 | Sub-type of the gases, e.g. 'HIT[1], HIT[2]' | |
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ATMOSPHERE-ABUN | S300 | Abundance of gases. The values can be assumed to be same across all altitudes/layers [%,ppmv,ppbv,pptv,m-2], or as a multiplier [scaler] to the provided vertical profile | |
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ATMOSPHERE-UNIT | S300 | Unit of the ATMOSPHERE-ABUN field, % / ppmv / ppbv / pptv / m2:'molecules/m2' / scl:'scaler of profile' | |
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ATMOSPHERE-TAU | S300 | For expanding cometary coma, this field indicates the photodissociation lifetime of the molecules [s] | |
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ATMOSPHERE-NAERO | 0 | 20 | Number of aerosols to include in the simulation |
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ATMOSPHERE-AEROS | S300 | Name of the aerosols to include in the simulation | |
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ATMOSPHERE-ATYPE | S300 | Sub-type of the aerosols | |
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ATMOSPHERE-AABUN | S300 | Abundance of aerosols. The values can be assumed to be same across all altitudes/layers [%,ppm,ppb,ppt,Kg/m2], or as a multiplier [scaler] to the provided vertical profile | |
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ATMOSPHERE-AUNIT | S300 | Unit of the ATMOSPHERE-AABUN field, % / ppmv / ppbv / pptv / m2:'molecules/m2' / scl:'scaler of profile' | |
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ATMOSPHERE-ASIZE | S300 | Effective radius of the aerosol particles. The values can be assumed to be same across all layers [um, m, log(um)], or as a multiplier [scaler] to the provided size vertical profile | |
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ATMOSPHERE-ASUNI | S300 | Unit of the size of the aerosol particles | |
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ATMOSPHERE-NMAX | 0 | 100 | When performing scattering aerosols calculations, this parameter indicates the number of n-stream pairs - Use 0 for extinction calculations only (e.g. transit, occultation) |
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ATMOSPHERE-LMAX | 0 | 100 | When performing scattering aerosols calculations, this parameter indicates the number of scattering Legendre polynomials used for describing the phase function - Use 0 for extinction calculations only (e.g. transit, occultation) |
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ATMOSPHERE-DESCRIPTION | S200 | Description establishing the source/reference for the vertical profile | |
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ATMOSPHERE-LAYERS | 0 | 1500 | Number of layers of the atmospheric vertical profile |
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ATMOSPHERE-LAYERS-MOLECULES | S500 | Molecules quantified by the vertical profile | |
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ATMOSPHERE-LAYER | S500 | Values for that specific layer: Pressure[bar], Temperature[K], gases[mol/mol], aerosols [kg/kg] - Optional fields: Altitude[km], X_size[m, aerosol X particle size] | |
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ATMOSPHERE-GCM-PARAMETERS | S500 | Parameters defining the 3D General Circulation Model grid: num_lons, num_lats, num_alts, lon0, lat0, delta_lon, delta_lat, variables (csv) | |
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ATMOSPHERE-JETS | S500 | Parameters (fraction,longitude,latitude,velocity[m/s],width[deg]) related to outgassing jets in exospheres | |
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SURFACE-MODEL | S300 | Type of scattering model describing the surface, and the model parameters (coma separated) | |
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SURFACE-PHASEMODEL | S300 | Phase function model and parameters (coma separated) | |
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SURFACE-MIXING | S50 | Type of mixing of surface components - Additional parameters added coma separated | |
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SURFACE-TEMPERATURE | 0 | 1e5 | Temperature of the surface [K] |
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SURFACE-ALBEDO | 0 | 1.0 | Albedo the surface [0:non-reflectance, 1:fully-reflective] |
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SURFACE-EMISSIVITY | 0 | 1.0 | Emissivity of the surface [0:non-emitting, 1:perfect-emitter] |
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SURFACE-GAS-RATIO | 0 | 1e6 | For expanding cometary coma, this value indicates an scaling value for the dust in the coma |
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SURFACE-GAS-UNIT | S50 | Unit of the dust abundance, [ratio] is dust/gas mass ratio, while [afrho] is the Afrho value and [lafrho] is log[Afrho/Q] | |
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SURFACE-NSURF | 0 | 20 | Number of components describing the surface properties [areal mixing] |
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SURFACE-SURF | S300 | Name of surface components to be included in the simulation | |
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SURFACE-TYPE | S300 | Sub-type of the surface components | |
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SURFACE-ABUN | S300 | Relative abundance of the surface components. For the remaining abundance, average surface albedo/emissivity will be considered | |
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SURFACE-UNIT | S300 | Unit of the SURFACE-ABUN field, % / ppm / ppv | |
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SURFACE-THICK | S300 | Thickness for each surface component [um] | |
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GENERATOR-RANGE1 | 1e-5 | 1e7 | Lower spectral range for the simulation |
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GENERATOR-RANGE2 | 1e-5 | 1e7 | Upper spectral range for the simulation |
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GENERATOR-RANGEUNIT | S10 | Unit of the GENERATOR-RANGE fields, um / nm / mm / An:'Angstrom' / cm:'Wavenumber [cm-1]' / MHz / GHz / kHz | |
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GENERATOR-RESOLUTION | 1e-6 | 1e8 | Spectral resolution for the simulation. PSG assumes that the sampling resolution is equal is to the instrumental resolution, yet radiative transfer resolutions are always performed at the necessary/higher resolutions in order to accurately describe the lineshapes |
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GENERATOR-RESOLUTIONUNIT | S10 | Unit of the GENERATOR-RESOLUTION field, RP:'Resolving power' / um / nm / mm / An:'Angstrom' / cm:'Wavenumber [cm-1]' / MHz / GHz / kHz | |
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GENERATOR-RESOLUTIONKERNEL | S1 | Convolution kernel applied to the spectra, default is 'N' | |
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GENERATOR-GAS-MODEL | S1 | Flag indicating whether to include molecular signatures as generated with PUMAS or CEM [Y/N] | |
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GENERATOR-CONT-MODEL | S1 | Flag indicating whether to include continuum signatures as generated by the surface, the star (when in the field) and dust/nucleus (when synthesizing comets) [Y/N] | |
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GENERATOR-CONT-STELLAR | S1 | Flag indicating whether to include stellar absorption signatures in the reflected sunlight / stellar spectra [Y/N] | |
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GENERATOR-TRANS-SHOW | S1 | Flag indicating whether we are synthesizing planetary spectra as observed with a ground-based telescope. This flag will ensure that the noise module properly includes telluric signatures | |
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GENERATOR-TRANS-APPLY | S1 | Flag indicating whether to show the spectra as observed and multiplied by the telluric transmittance [Y] | |
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GENERATOR-TRANS | S20 | Keyword [SS-WW] indicating the site [SS] and water abundance [WW]. Values of SS are 00:'0m (sea level)', 01:'2,600m (8,500 feet)', 02:'4,200m (14,000 feet)', 03:'14,000m (46,000 feet)', 04:'35,000m (120,000 feet)'. Values of WW are 00:'10% tropical', 01:'30% tropical', 02:'70% tropical', 03:'100% tropical' | |
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GENERATOR-RADUNITS | S20 | Radiation unit for the generated spectra, see full list of permitted keywords in the 'Modeling > Radiation Units' section | |
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GENERATOR-LOGRAD | S1 | Flag indicating whether to show the spectra employing a logarithmic scale | |
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GENERATOR-TELESCOPE | S10 | Type of telescope, SINGLE:'single dish telescope or instrument', ARRAY:'Interferometric array', CORONA:'Coronagraph', AOTF or LIDAR | |
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GENERATOR-BEAM | S30 | Full width half-maximum (FWHM) of the instrument's beam or field-of-view (FOV), also available is major axis, rotation and if square (S) | |
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GENERATOR-BEAM-UNIT | S20 | Unit of the GENERATOR-BEAM field, arcsec / arcmin / degree / km / diameter:'beamsize in terms of the planet's diameter' / diffrac:'defined by the telescope diameter and center wavelength' | |
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GENERATOR-DIAMTELE | 1e-5 | 1e5 | Diameter of the main reflecting surface of the telescope or instrument [m] |
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GENERATOR-TELESCOPE1 | S100 | For interferometers, the number of telescopes; for coronagraphs, the instrument's contrast | |
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GENERATOR-TELESCOPE2 | S100 | This field indicates the zodi-level (1.0:Ecliptic pole/minimum, 2.0:HST/JWST low values, 10.0:Normal values, 100.0:Close to ecliptic/Sun), or order number for the AOTF system. For coronagraphs, this field indicates allows two entries: the exozodi level and the local zodiacal dust level | |
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GENERATOR-TELESCOPE3 | S4000 | For coronagraphic observations, the inner working angle (IWA) in units of [L/D] | |
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GENERATOR-NOISE | S20 | Keyword identifying the noise model to consider, NO:'None', TRX:'Receiver temperature', RMS:'Constant noise in radiation units', BKG:'Constant noise with added background', NEP:'Power equivalent noise detector model', D*:'Detectability noise detector model', CCD:'Image sensor' | |
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GENERATOR-NOISETIME | 0.0 | 1e7 | Exposure time per frame [sec] |
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GENERATOR-NOISEFRAMES | 1 | 1e20 | Number of exposures |
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GENERATOR-NOISEPIXELS | S4000 | Total number of pixels that encompass the beam (GENERATOR-BEAM) and the spectral unit (GENERATOR-RESOLUTION) | |
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GENERATOR-NOISE1 | S4000 | First noise model parameter - For RMS, 1-sigma noise; for TRX, the receiver temperature; for BKG, the 1-sigma noise; for NEP, the sensitivity in W/sqrt(Hz); for DET, the sensitivity in cm.sqrt(Hz)/W; for CCD, the read noise [e-] | |
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GENERATOR-NOISE2 | S4000 | Second noise model parameter - For RMS, not used; for TRX, the sideband g-factor; for BKG, the not used; for NEP, not used; for DET, the pixel size [um]; for CCD, the dark rate [e-/s] | |
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GENERATOR-NOISEOEFF | 0.0 | 1.0 | Total throughput of the telescope+instrument, from photons arriving to the main mirror to photons being quantified by the detector [0:none to 1:perfect]. The user can provide wavelength dependent values as neff@wavelength[um] (e.g., '0.087@2.28,0.089@2.30,0.092@2.31,0.094@2.32,...') |
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GENERATOR-NOISEOEMIS | 0.0 | 1.0 | Emissivity of the telescope+instrument optics [0 to 1] |
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GENERATOR-NOISEOTEMP | 0.0 | 1e4 | Temperature of the telescope+instrument optics [K] |
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GENERATOR-INSTRUMENT | S500 | Text describing if an instrument template was used to define the GENERATOR parameters | |
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GENERATOR-NOISEWELL | 0 | 1E9 | Well depth [e-] of each pixel detector |
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GENERATOR-GCM-BINNING | 1 | 1e4 | Spatial binning applied to the GCM data when computing spectra. 1: Full resolution |
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RETRIEVAL-GAMMA | 0 | 1e3 | The parameter Gamma (or Levenberg-Marquart parameter) is the extra regularization parameter (e.g., 0:Classic LM, 1:classic Rodgers' formalism, 10:Heavily tailored to the a-priori) |
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RETRIEVAL-NEST | S100 | Parameters for the nested sampling retrieval method | |
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RETRIEVAL-RANGEUNIT | S10 | Spectral unit of the user-provided data for the retrieval, um / nm / mm / An:'Angstrom' / cm:'Wavenumber [cm-1]' / MHz / GHz / kHz | |
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RETRIEVAL-RESOLUTION | 1e-6 | 1e8 | Instrument's spectral resolution [FWHM] of the user-provided data. This value is independent of the sampling rate of the data, and refers to the actual spectral resolution of the instrument |
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RETRIEVAL-RESOLUTIONUNIT | S10 | Unit of the RETRIEVAL-RESOLUTION field, RP:'Resolving power' / um / nm / mm / An:'Angstrom' / cm:'Wavenumber [cm-1]' / MHz / GHz / kHz | |
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RETRIEVAL-FLUXSCALER | 0 | 1E30 | Scaling value to be applied to all fluxes of the user-provided data file |
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RETRIEVAL-FREQSHIFT | S50 | Frequency/wavelength corrections (0th, 1st and 2nd orders) to be applied to the data | |
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RETRIEVAL-FLUXLABELS | S100 | Labels for the columns of the data file | |
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RETRIEVAL-FITGAIN | -1 | 10 | Polynomical degree of the instrument's gain function, -1:None, 0:Constant, 1:Sloped, 2:Quadratic, etc |
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RETRIEVAL-FITGAIN-PHOTOMETRIC | S1 | Flag indicating whether to preserve the photometric information of the data (zeroth order of gain fitting) [Y:Disable 0th order / N:Enable] | |
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RETRIEVAL-REMOVEOFFSET | -1 | 10 | Polynomical degree of the residual offset, -1:None, 0:Constant, 1:Sloped, 2:Quadratic, etc |
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RETRIEVAL-REMOVEFRINGE | 0 | 9 | Maximum number of spectral fringes to be removed from the data |
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RETRIEVAL-FITSTELLAR | S1 | Flag indicating whether to fit the intensity of the solar/stellar features [Y/N] | |
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RETRIEVAL-FITFREQ | S1 | Flag indicating whether to refine the spectral calibration [Y/N] | |
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RETRIEVAL-FITRESOLUTION | S1 | Flag indicating whether to fit the spectral resolution [Y/N] | |
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RETRIEVAL-FITTELLURIC | S1 | Flag indicating whether to fit the telluric features [Y/N]. This is done by perturbing the selected telluric column/water abundances | |
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RETRIEVAL-NVARS | 0 | 1000 | Number of model variables to be retrieved |
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RETRIEVAL-VARIABLES | S30000 | Name of the variables of the retrieval (comma separated) | |
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RETRIEVAL-VALUES | S30000 | A-priori and resulting values of the retrieval parameters (comma separated) | |
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RETRIEVAL-SIGMAS | S30000 | Resulting 1-sigma uncertainties (corrected by chi-square) of the retrieval parameters (comma separated) | |
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RETRIEVAL-MIN | S30000 | Lower boundary permitted for each parameter (comma separated) | |
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RETRIEVAL-MAX | S30000 | Upper boundary permitted for each parameter (comma separated) | |
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RETRIEVAL-UNITS | S30000 | Magnitude unit of the a-priori and boundary entries (comma separated) | |
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RETRIEVAL-STATUS | S30 | Flag indicating the status of the retrieval suite (e.g., RUNNING, OK) | |