T2.3: Residual pattern analysis

[w2naf]

Description

Investigate systematic patterns in the validation residuals (HamSCI virtual height minus Digisonde virtual height) to understand the instrument's error characteristics.

Analysis Required

• Do residuals correlate with time of day? (Plot residual vs. local time)
• Do residuals correlate with virtual height itself? (e.g., larger errors at higher virtual heights)
• Are there systematic biases? (HamSCI consistently reading higher or lower)
• Are there outlier events? If so, what was happening ionospherically?
• Is there a dependence on geomagnetic activity (Kp index)?
  • Retrieve Kp from NOAA or GFZ for the analysis period
• Consider whether the distance between HamSCI (Spring Brook Twp, PA) and the reference Digisonde contributes to residuals

Figures

• Residual vs. time-of-day plot
• Residual vs. virtual height plot
• Residual vs. Kp (if sufficient geomagnetically active days exist in the dataset)

Acceptance Criteria

• Residual vs. time-of-day plot generated
• Residual vs. virtual height plot generated
• Assessment of whether systematic biases exist
• Outlier events identified and discussed
• Written interpretation

Timeline

• Start: Apr 10, 2026
• Due: Apr 17, 2026
• Milestone: Dayton Hamvention 2026
• Depends on: T2.1: Extend validation dataset to 2-3 months #7

Context

Phase 2 of Track 1. Understanding residual patterns helps characterize measurement uncertainty and identify potential instrument issues. See plans/track1-workplan.md.