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Aurora Integrating Nephelometer

The Aurora is an integrating nephelometer used for measuring light scattering properties of aerosols at multiple wavelengths.

Data Format

  • File format: CSV file
  • Sampling frequency: 1 minute
  • File naming pattern: *.csv
  • Timestamp column: Date / time local
  • Column naming conventions:
    • UV BCc, Blue BCc, Green BCc, Red BCc, IR BCc
    • Biomass BCc, Fossil fuel BCc
    • Delta-C, AAE, BB (%)

Measurement Parameters

The Aurora provides measurements at multiple wavelengths and source apportionment:

  • B, G, R: Total scattering coefficients at blue, green, and red wavelengths (Mm⁻¹)
  • BB, BG, BR: Backscattering coefficients at blue, green, and red wavelengths (Mm⁻¹)
  • BB mass: Biomass burning BC mass concentration (ng/m³)
  • FF mass: Fossil fuel BC mass concentration (ng/m³)
  • Delta-C: Difference between UV and IR channels (ng/m³)
  • AAE: Absorption Ångström Exponent
  • BB: Biomass burning percentage (%)

Data Processing

Data Reading

  • Parses timestamps from 'Date / time local' column
  • Standardizes column names for consistent output
  • Converts all measurement values to numeric format
  • Handles different column naming conventions
  • Maps wavelength-specific BC concentrations to standardized names

Quality Control

  • Removes physically impossible values (negative or > 2000 Mm⁻¹)
  • Ensures physical consistency:
    • Backscattering must be less than total scattering
    • Blue > Green > Red (Rayleigh scattering principle)
  • Applies time-aware IQR filtering with 1-hour windows
  • Ensures data completeness across all channels

Output Data

The processed data contains the following columns:

  • Time index: Data acquisition time
  • B, G, R: Total scattering coefficients (Mm⁻¹)
  • BB, BG, BR: Backscattering coefficients (Mm⁻¹)
  • BB mass: Biomass burning BC (ng/m³)
  • FF mass: Fossil fuel BC (ng/m³)
  • Delta-C: UV-IR difference (ng/m³)
  • AAE: Absorption Ångström Exponent
  • BB: Biomass burning percentage (%)

Notes

  • Provides real-time measurement of black carbon concentrations with source apportionment
  • Distinguishes between fossil fuel combustion and biomass burning contributions
  • Maintains physical consistency between measurements
  • Automatically handles different column naming conventions