New remote sensing approaches for light pollution observations

Supervisor: Stefan Wallner

Contact information:  stefan.wallner@univie.ac.at

Expected duration: 8-12 months

 

Project description & Goals:

As we are now seeing, many cities worldwide, are changing current existing and mostly outdated lighting situation systems from inefficient lamps of past generations to Light Emitting Diodes (LEDs), often emitting large amounts of light in short wavelengths (blue). This foregoing will lead to major issues for light pollution research in the future. The majority of gathered data originate from either one-dimensional photometric measurements by detecting the brightness of the sky's zenith luminosity, logged by so-called ‘Sky Quality Meter’-devices, or from satellite data, mostly obtained by the ‘Visible Infrared Imaging Radiometer Suite’ (VIIRS) satellite. Both methods lead to difficulties in the long run, as their spectral sensitivities show weaknesses, being mostly blind to short wavelengths. Even if cities become brighter, by changing the colour of light emitting sources, existing devices are going to predict a decrease in skyglow. One of the aims of the project is to quantify this effect, taking a closer look on the true effectiveness of current used devices and their data analyses, and also try to find novel approaches in their usage. Satellite data, especially from VIIRS' Day/Night Band, will be used to analyse surface radiances and to compare data with ground-based observations. A concept of important parameters for future devices shall be developed in the end of the study.

 

Working plan & Milestones (including final thesis):

 

  • Month 1-2: Collect information about current existing measurement devices and get in touch with satellite data.
  • Month 3-4: Perform an intercomparison study between various observational methods and their effectiveness (ground-based and satellites).
  • Month 5-6: Compare and work on results, find strengths and weaknesses of existing techniques. 
  • Month 7-8: Develop a concept of important parameters for future instruments and devices.

 

References:

Hänel, A. et al. Measuring night sky brightness: Methods and challenges. J. Quant. Spectrosc. Radiat. Transf. 2018, 205, 278-290.