CAFE

CAFE is a data-assimilative thermospheric density driver-estimation approach designed to improve MSIS-based neutral density calculations for satellite-drag applications. The approach produces Neutral Density Equivalent Proxy inputs, or NDEPs, which are effective solar and geomagnetic driver values inferred from satellite-drag observations rather than taken directly from standard observed or issued space-weather indices.

CAFE uses an MSIS 2.1 ensemble as the background model system and assimilates orbit-averaged drag information from approximately 70 calibration objects derived from ground-based observations. Through data assimilation, CAFE estimates model-effective solar and geomagnetic forcing values that make MSIS reproduce observed drag/density behavior more accurately. These NDEP inputs can then be used to run MSIS in a drag-optimized, reanalysis-style mode. The CAFE NDEP dataset currently spans roughly 2014–2025.

• NDEP’s incorporate a chain of processes and parametrizations into a single value. It is useful for diagnostic and re-analysis but also model specific.
• Model limitations: At seasonal timescales, data-assimilate diverges from HASDM at lower altitudes (<300 km).
• Only two driver estimates are included. Need to advance towards more complete driver estimate but to accomplish it needs for more data.

date, UT, geodetic altitude, latitude, longitude

• Total mass density
• Helium number density
• Oxygen(O) number density
• Oxygen (O2) number density
• Nitrogen (N) number density
• Nitrogen (N2) number density
• Argon number density
• H Hydrogen number density
• Anomalous oxygen number density
• Exospheric temperature
• temperature at altitude
• Nitric Oxide (NO) number density