UARS PEM VMAG AC: Upper Atmosphere Magnetic Field Fluctuations

From October 1, 1991 to August 23, 2005, the Particle Environment Monitor (PEM) on the UARS spacecraft measured high-frequency magnetic field fluctuations in Earth's upper atmosphere. The Vector Magnetometer (VMAG) AC product provides the peak amplitude of the AC component filtered between 2.5 and 50 Hz, with one daily file covering latitudes between -57 and +57 degrees. Data is stored in network binary format, representing digitized peak detector outputs from the instrument.

Use Cases

• Analyzing high-frequency magnetic field disturbances in the thermosphere, mesosphere, and stratosphere based on the 2.5-50 Hz filtered AC component.
• Studying the spatial distribution of magnetic field fluctuations based on the latitude coverage from -57 to +57 degrees.
• Investigating temporal trends in upper-atmosphere magnetic activity based on the daily data files spanning over 13 years.
• Correlating magnetic field AC signals with other particle measurements from the PEM instrument suite.
• Validating models of charged particle injection into the atmosphere based on the measured peak amplitudes from the X, Y, and Z vector components.

Strengths

• Provides a long-term, continuous record from October 1991 to August 2005.
• Offers specific technical details on measurement methodology, including filter ranges (2.5-50 Hz), time constants (4.7 s), and full-scale values (100 nT for X/Z, 10 nT for Y).
• Data is hosted on multiple authoritative platforms (NASA Earthdata and Data.gov), indicating established provenance.

Limitations

• Column names and data structure are unknown, requiring consultation of a separate format guide.
• No in-flight calibration is provided for the AC peak detection electronics.
• The dataset's last updated metadata shows conflicting dates (2005-08-23 and 2026-04-09), suggesting potential metadata freshness issues.

Provenance

Source

GES_DISC (NASA Goddard Earth Sciences Data and Information Services Center)

Collection Method

Measured by the Vector Magnetometer (VMAG) instrument on the Upper Atmosphere Research Satellite (UARS) Particle Environment Monitor (PEM).

Time Range

1991-10-01 to 2005-08-23

Freshness

2026-04-09 21:25:09.047320

Geography

Latitude range: -57 to +57 degrees.