ICON Public Data

ICON Rules of the Road (PDF 395KB)

ICON data products summary

The ICON data products are available online. The retrieved quantities are all provided with appropriate uncertainties, and all variables are described in detail in the associated var_notes attribute for each variable. Attention should be paid to the data quality flags associated with each product. The version of the retrieval is reported in the filename, followed by a revision number indicating the number of times the data have been processed in the ICON SDC.

2.1 Neutral Wind profiles, Line of Sight

This data product contains the retrieved neutral wind velocity along the line of sight (LOS) of one of the two MIGHTI instruments —Ahead (A) and Behind (B)— retrieved from observations of the Doppler shift of 557.7 and 630.0 nm atomic oxygen emissions. Daytime observations of the red line (630.0 nm) emission span the altitude range of ~180 to 300 km while observations of the green line (557.7 nm) emission span the altitude range of 90 to ~190 km. Nighttime observations of the red line emission span the altitude range of ~210 to 300 km while those of the green line span 90 to ~109 km. Daytime observations are provided at a 30-s cadence while nighttime observations are provided at a 60-s cadence.

Documentation for 2.1 (PDF)

2.2 Neutral Wind profiles, zonal and meridional

This data product combines the line of sight winds from both MIGHTI-A and MIGHTI-B contained in the Level 2.1 data product to provide neutral wind vectors referenced to geographic and geomagnetic coordinate systems. It combines the winds from the two most closely-associated LOS retrievals.

Documentation for 2.2 (PDF)

2.3 Neutral Temperatures

This data product contains the retrieved temperature of the thermospheric temperature determined from the shape of the O2 762 nm band emission. The observations are continuous during the orbit in the 90-105 km altitude range with temperatures available at higher altitudes in daytime. The product is obtained every 30 s in daytime and 60 s at night.

Documentation for 2.3 (PDF)

2.4 Daytime thermospheric O/N2 ratio

This data product contains the retrieved column density ratio of thermospheric atomic oxygen to molecular nitrogen.  These two constituents are the primary factors in considering the production and loss of ionospheric densities, so much so that the simple ratio of the two is highly informative. As well, the ratio is a sensitive indicator of storm-time compositional changes resulting from heating and dynamics. The retrievals are informed by the observations of the two wavelength channels of the ICON FUV instrument that measure photo-electron produced emissions of the two constituents in daytime at 135.6 nm and 155 nm, at tangent altitudes both above and below the horizon. The field of view of the instrument is split up and 6 neighboring profiles are all collected every 12 seconds. The instruments 24º vertical field of view provide data to inform both a limb retrieval, where densities of atmospheric O and N2 are each retrieved, and a disk product where the line of sight intensities are used to retrieve a column integrated O/N­2 product. The disk product is available in the 2.4 NetCDFs now, with limb products coming later in 2020.

Documentation for 2.4 (PDF)

2.5 Nighttime ionospheric O+ profiles

This data product contains the retrieved O+ density profiles of the nighttime ionosphere over a 24-hour period of the ICON mission as well as all other data necessary to use the product such as retrieval locations and measurement times. These retrievals are informed by observations from the ICON FUV instrument, as it provides 6 neighboring limb profiles of the atomic oxygen emission at a wavelength of 135.6 nm with 12-s integrations, available in the Level 1 FUV data.These are obtained continuously by the shortwave FUV channel (with its passband centered at 135.6 nm) except in the high radiation region of the South Atlantic anomaly, and that are useful for O+ density retrievals in night time when photoelectron-produced emissions are not present (See 2.4 Daytime thermospheric composition product). Nominally 6 stripes are used, and each stripe samples a 3-degree wide field of view. O+ density profiles are estimated separately for each stripe.

Documentation for 2.5 (PDF)

2.6 Daytime ionospheric O+ profiles

This product contains height density profiles of ionospheric O+ in the daytime, and from these retrievals the corresponding height and peak density of the F2-layer. It is informed by measurements made by the ICON EUV instrument of O+ emission features at 83.4 and 61.7 nm. The former is a bright emission that is produced in the lower thermosphere and resonantly scattered by O+ ions that dominate the composition of the ionospheric F-layer. The latter provides a measurement of the source of the 83.4 emission, as it is produced in a similar manner but does not undergo scattering. These retrievals are calculated for every 12-s measurement of the EUV instrument obtained at local times starting mid-morning through to the dusk terminator.

Documentation for 2.6 (PDF)

2.7 Ionospheric plasma velocity and density

This product contains the density and velocity of the plasma measured at the location of the ICON satellite. It is retrieved from the two velocity measurements by the IVM instrument, a ram velocity from the RPA and a cross-track velocity from the IDM. The velocity is calculated in reference to both geographic and magnetic coordinate systems. It provides other quantities as well, including a measure of the relative abundance of O+ and H+ and the plasma temperature.

Documentation for 2.7 (PDF)

ICON skin is based on Greytness by Adammer
Background image, courtesy of NASA, is a derivitave of photograph taken by D. Pettit from the ISS, used under Creative Commons license