Swarm4Anom provides continuation of studies initialized with in-situ measurements of electron density obtained by the Langmuir Probe on-borad the CNES satellite DEMETER. Methodology for detection of WSA-like phenomena was introduced in the paper:

Seasonal trends of nighttime plasma density enhancements in the topside ionosphere

Detection of WSA-like phenomena is based on the introduced dimensionless index I_NDD (Normalized Density Difference Index)

Some trial image

I_NDD - indicator of an anomaly

About the index:

  1. It is assumed that I_NDD defined as a differential measure of in-situ electron density obtained in measurements separated by 12 hours (analogy to day/night).
  2. Under regular condition, negative values represent typical ionospheric behavior following diurnal cycle, while positive values should indicate possible nighttime enhancements.
  3. INDD is additionally normalized, therefore obtains values within the limits from, -1 to 1, making it easily adaptable parameter for comparison with other data sources.
  4. Applicability of the index for the detection of NPDEs depends on local times selection and effective separation of daytime and nighttime measurements.
  5. Nominal nighttime measurements are defined for local times (LT) in the range 20:00 - 07:00 ( LT derived for equatorial passing in the descending node) - For this type of registrations index is flagged with value '1'
  6. If for ascending node LT is beyond the range 20:00 - 07:00 - '-1' flag is used for interpretation.
The Swarm4Anom project is funded by the European Space Agency under contract: ESA Contract No. 4000112769/14/NL/FF/gp Project was led by Space Research Centre PAS in cooperation with a start-up OBSEE