Anomaly Detection System

Cutoff Point method

Number of Outliers

Number of outliers (over 99.9% quantile) for each station from 1998 to 2020

Malfunction and Delay

Notation

  • -9995 and X: malfunction
  • -9996: delayed return
  • HR: Hourly Rainfall
  • PHR: Previous Hourly Rainfall

Table of Outliers due to Malfunction (descending order in HR)

Table of Delayed Outliers (descending order in HR)

Map for Malfunction and Delay

Map for Outliers due to Malfunction

Map for Outliers due to Delay

PCA

Notation(OBS=Observations)

  • B1: OBS at some hours were higher than that of nearby stations
  • B2: Observed trace; nearby stations, rainfalls
  • B3: Did not observe OBS due to malfunctions
  • B4: Did not observe OBS due to delays
  • B5: Observed rainfalls; nearby stations, trace
  • B6: Observed rainfalls; nearby stations did not due to malfunctions
  • B7: Observed rainfalls; nearby stations did not due to delays
  • B8: Delayed return of accumulated rainfall records
  • B9: Rainfall trend was different from that of nearby stations