Daily PRA Nighttime Detection

Last updated on: 21 Apr 2026, 13:02 (Japan Local Time)

Recent Anomaly Summary (Last 5 Anomalies)

Observation range	Anomaly Time(s)	PRA Threshold	Anomalous PRA values	$S_Z$ during anomalies	$S_G$ during anomalies	Remarks	Plot
31/07/2025 20:00 - 01/08/2025 04:00	00:00–01:00	5.95	6.5	52.8859	8.1334	Anomaly due to drop in S_G
30/12/2025 20:00 - 31/12/2025 04:00	22:00–23:00	12.45	13.12	80.5387	6.1407	Anomaly due to increase in S_Z
30/10/2025 20:00 - 31/10/2025 04:00	21:00–22:00, 00:00–01:00	12.40	-	-	-	Anomaly due to increase in S_Z, Anomaly due to drop in S_G
29/12/2025 20:00 - 30/12/2025 04:00	23:00–00:00	5.32	5.69	243.9573	42.9096	Anomaly due to increase in S_Z
29/09/2025 20:00 - 30/09/2025 04:00	00:00–01:00	13.08	14.42	96.6674	6.7017	Anomaly due to increase in S_Z

---

About This Project

This repository provides automated daily analysis of nighttime geomagnetic field data from the Kakioka observatory (KAK) using the Polarization Ratio Analysis (PRA) method.

• Detection Time Window: 20:00–04:00 (Local Time)
• Frequency Band: 0.01–0.05 Hz
• Anomalies flagged when PRA > threshold
• Threshold calculated based on weighted mean of recent days
• Results stored in a cumulative .mat file for long-term monitoring
• README updated automatically each day via GitHub Actions

Author

• Nur Syaiful Afrizal