SET has teamed with Leidos, Computational Physics, Inc. (CPI), the University of Florida (UFL), Utah State University (USU), and Vesperix Corp. (VI), to develop an innovative and comprehensive approach to the DARPA AtmoSense program. Our team's program is called Sensing Tropospheric Events Remotely using Electromagnetics Optimally (STEREO) and focuses on advancing the state of the art to detect modifications of the total electron content (TEC) of the ionosphere. The STEREO program is demonstrating Very Low Frequency (VLF) holography of the D-region of the ionosphere to observe ionospheric events at long distances (well over the horizon) with high spatial (< 100km) and temporal (< 10s) resolution. This is being coupled with improvements in atmospheric characterization and propagation modeling to reduce uncertainty in the association between an ionospheric event with a tropospheric or near surface event. SET's role in this work is to provide the climatological uncertainties in neutral atmosphere and ionosphere states, whether they be solar minimum/maximum, geomagnetic storms, seasonal, or altitudinal. This page links to that uncertainty as determined from SET's High Accuracy Satellite Drag Model (HASDM) density database for neutral thermosphere densities as well as from USU's Global Assimilation of Ionosphere Measurements (GAIM) database for ionosphere parameters.

Thermosphere and ionosphere density uncertainty plots

Thermosphere densities: from the SET HASDM density database



Ionosphere densities: from the USU GAIM database




Neutral atmosphere density summary

Through the STEREO AtmoSense project SET has been able to place the HASDM, MSISV2, MSIS-UQ, EXTEMPLAR, J71, and USU LIDAR data on a common plot for the first time. The data is for neutral density over Logan Utah (41N/248E) on October 29, 2003 at 03UT, i.e., at the start of the 2003 Halloween storm period. Uncertainties for each of the measurements and modeled data are shown on the plot, including those from CHAMP satellite. Publication references for each of the datasets is shown in the figure legend. One notes that the uncertainties are small below the lower thermosphere. Above the turbo pause at 12o–125 km the uncertainties begin to grow larger and, during the October 2003 Halloween storm period, the variability of the density in the upper thermosphere becomes quite large.

A publication quality jpeg of this image can be obtained here. For use in publications, please use the acknowledgement: “Provided courtesy of Space Environment Technologies, 2023.”

SET Subcontract Partners

Utah State University provides the historical GAIM ionosphere densities from which uncertainties are derived