UARS PEM AXIS2: Daily X-Ray Particle Spectra from Earth's Upper Atmosphere

UARS Particle Environment Monitor (PEM) level 2 data provides high-resolution X-ray spectral measurements from the Atmosphere X-Ray Imaging Spectrometer unit 2 (AXIS2). The dataset contains daily files of charged particle intensity across an energy range of roughly 2 keV to 300 keV, recorded by eight directionally-staggered pixels. It covers a temporal range from October 1, 1991 to August 23, 2005, with spatial coverage between -80 and +80 degrees latitude.

Use Cases

• Analyzing solar energetic particle flux variations over a 14-year period based on the daily temporal resolution.
• Studying the spatial distribution of X-ray flux in the upper atmosphere using the eight directionally-viewing pixels.
• Correlating particle injection events with other solar and geomagnetic activity datasets based on the high-resolution spectral energy data (2-300 keV).
• Modeling the impact of charged particles on atmospheric chemistry based on the type and amount of particles measured.

Strengths

• Provides a long-term, consistent time series covering over 14 years of solar cycle activity.
• Offers directional particle flux data from eight distinct sensor pixels, allowing for spatial analysis.
• Contains high-resolution spectral data across a broad energy range (2 keV to 300 keV).

Limitations

• Data format is network binary, requiring specific tools or guides for interpretation, as column details are not provided.
• Metadata completeness is low; specific row counts, file sizes, and detailed column descriptions are unavailable.
• Conflicting last-update dates exist between sources (2005 vs. 2026), creating uncertainty about metadata freshness.

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Collected by the Particle Environment Monitor (PEM) instrument's AXIS2 unit on the Upper Atmosphere Research Satellite (UARS) spacecraft.

Time Range

1991-10-01 to 2005-08-23

Freshness

2026-04-09 21:25:28.961628

Geography

Global coverage between -80 and +80 degrees latitude.