Assessing the contribution from different parts of Canary islands to the hemispheric spectral sky radiance levels over European Northern Observatories

Transcription

1 Assessing the contribution from different parts of Canary islands to the hemispheric spectral sky radiance levels over European Northern Observatories M. Aubé (a b c) (a) Cégep de Sherbrooke, Québec, Canada; (b) Université de Sherbrooke, Québec, Canada; (c) Centre de Recherche en Astrophysique du Québec, Canada Funding for this research was provided by the fond québécois pour la recherche sur la nature et les technologie (FQRNT), by Éducation, loisirs et sports Québec and by Instituto de Astrofisica de Canarias.

2 Outline Important variables involved Modeling ILLUMINA Model features Canary island 2010 experiment Modeling experiment Light pollution detector : SAND-3 Typical spectrum and key wavelength Model input Results contribution maps - sensitivity maps - all sky radiances References

3 Important variable involved

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5 ILLUMINA Model features GPL Licence Heterogeneity of the environment (topography, ground reflectance, light sources geographical distribution) Spectral dependance Light source angular output pattern (horizontal isotropy is assumed) Molecule and aerosol optics: molecules -> scattering aerosols -> scattering & absorption molecules and aerosols extinction along the light path Computation of shadows (grid and subgrid scales) Up to 99 source types per horizontal cell 3D computation (1024 x 1024 x 50 levels) Logarithmic vertical scale which allow a better simulation near light sources where atmospheric concentration and light intensity are higher

6 Canary islands 2010 experiment Obs. Roque de los Muchachos La Palma (ORM) ORM OT Obs. Teide Tenerife (OT)

7 Modelling experiment Geographical domain 400 km x 300 km Spatial grid resolution 1 km 2 observation sites simulated OT, ORM 41 viewing angles Zenith angles = 0, 20, 45, 60, 70, 75 Azimuth angles = 0, 45, 90, 135, 180, 225, 270, aerosol optical depth 0.025, 0.05, 0.1, wavelengths 435 nm, 498 nm, 546 nm, 569 nm, 615 nm 2 periods Before midnight, after midnight Overall h cpu (12 years on one node)

8 Features: Light pollution detector: SAND-3 Web based control 2 nm resolution Robotized mount Heating Ventilation Webcam Oper. To: -20 C to 55 C CCD camera Handheld version used in Canary Islands Spectrometer Webcam

9 Typical spectrum and key wavelength OT, Tenerife 17 viewing angles Zenith angles = 0, 45, 70 Azimuth angles = 0, 45, 90, 135, 180, 225, 270, sites ORM, OT

10 Model input Shuttle Radar Topography Mission Band 1 and 3 also used Light output Pattern Inventory

11 Model input Knowledge from a local expert of the typical lighting devices used by regions along with typical after midnight reduction by regions (expert was Javier Diaz from Instituto de Astrofisica de Canarias) SAND spectral data for Tenerife at z=70 deg have been used to calibrate light inventory Aerosol optical depth have been determined with nearby AERONET sunphotometers and with a Microtops handheld sunphotometer Sea level atmospheric pressure from local meteo stations

12 Observatorio del Roque de los Muchachos Canary sky law. Contribution to zenith Hg 546 nm radiance over ORM

13 Observatorio del Roque de los Muchachos... Contribution to zenith HPS 569 nm radiance over ORM

14 Observatorio del Teide Canary sky law.. Contribution to zenith Hg 546 nm radiance over OT

15 Observatorio del Teide. Contribution to zenith HPS 569 nm radiance over OT

16 Sensitivity maps

17 Sensitivity maps (1) a place between Los Barros and Amagar (2) between El Pueblo and Bellido (3) 3 km north of El Paso (4) 1.5 km east of Puntagorda (5) 1.5 km ESE of San Antonio

18 All sky plots ORM OT Computed before midnight Na 569 nm radiance (W/nm/Sr)

19 Complete results and references Technical report: Related publication: Aube, M., Kocifaj, M., (2012) Using two light-pollution models to investigate artificial sky radiances at Canary Islands observatories Monthly notice of the royal astronomical society Vol. 422, Issue 1, pp Complete online data:

20 Ongoing and future works Casiana Munoz-Tunon (Spain) Javier Diaz (Spain) Alex Oscoz (Spain) Carlos Arencibia (Spain) Chris Elvidge (USA) Jean-Denis Giguere (Canada)

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26 Light Pollution : Theory, Modelling, and Measurements conference April , Smolenice castle, Slovak Republic Organisers: Miroslav Kocifaj (Slovak Republic) and Martin Aubé (Canada) Topics: Theoretical concepts for modelling light pollution Numerical tools and simulation experiments Effects of atmospheric aerosols and obstacles on light pollution Impact of spectral characteristics of light sources and reflecting surfaces Observational techniques and data products Design and evaluation of dark sky friendly lighting technologies Deadlines: Abstracts: October Early birds registration: January Fees: 350/400 EUR including reception, meals, coffee breaks, proceedings website: