Preprints
https://doi.org/10.5194/amt-2021-204
https://doi.org/10.5194/amt-2021-204

  26 Jul 2021

26 Jul 2021

Review status: this preprint is currently under review for the journal AMT.

Retrieval of aerosol properties using relative radiance measurements from an all-sky camera

Roberto Román1, Juan C. Antuña-Sánchez1, Victoria E. Cachorro1, Carlos Toledano1, Benjamín Torres2, David Mateos1, David Fuertes3, César López4, Ramiro González1, Tatyana Lapionok2, Oleg Dubovik2, and Ángel M. de Frutos1 Roberto Román et al.
  • 1Group of Atmospheric Optics (GOA-UVa), University of Valladolid, 47011, Valladolid, Spain
  • 2Laboratoire d’Optique Atmosphérique, CNRS, Lille 1 University, France
  • 3GRASP-SAS, Remote Sensing Developments, Villeneuve D’Ascq, France
  • 4Sieltec Canarias S.L., La Laguna, Spain

Abstract. This paper explores the potential of all-sky cameras to retrieve aerosol properties with GRASP code (Generalized Retrieval of Atmosphere and Surface Properties). To this end, normalized sky radiances (NSR) extracted from an all-sky camera at three effective wavelengths (467, 536 and 605 nm) are used in this study. NSR observations are a set of relative (uncalibrated) sky radiances in arbitrary units. NSR observations have been simulated for different aerosol loads and types with the forward radiative transfer module of GRASP, indicating that NSR observations contain information about the aerosol type as well as about the aerosol optical depth (AOD), at least for low and moderate aerosol loads. An additional sensitivity study with synthetic data has been carried out to quantify the theoretical accuracy and precision on the aerosol properties (AOD, size distribution parameters, etc.) retrieved by GRASP using NSR observations as input. As result, the theoretical accuracy on AOD is within ±0.02 for AOD values lower or equal than 0.4; while the theoretical precision goes from 0.01 to 0.05 when AOD at 467 nm varies from 0.1 to 0.5. NSR measurements recorded at Valladolid (Spain) with an all-sky camera for more than two years have been inverted with GRASP. The retrieved aerosol properties are compared with independent values provided by co-located AERONET (AErosol RObotic NETwork) measurements. AOD from both data sets correlate with determination coefficient (r2) values about 0.87. Finally, the novel multi-pixel approach of GRASP is applied to daily camera radiances together, by constraining the temporal variation in certain aerosol properties. This temporal linkage (multi-pixel approach) provides promising results, reducing the highly temporal variation in some aerosol properties retrieved with the standard (one by one or single-pixel) approach. This work implies an advance in the use of all-sky cameras for the retrieval of aerosol properties.

Roberto Román et al.

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2021-204', Reed Espinosa, 19 Aug 2021 reply

Roberto Román et al.

Roberto Román et al.

Viewed

Total article views: 369 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
279 83 7 369 6 3
  • HTML: 279
  • PDF: 83
  • XML: 7
  • Total: 369
  • BibTeX: 6
  • EndNote: 3
Views and downloads (calculated since 26 Jul 2021)
Cumulative views and downloads (calculated since 26 Jul 2021)

Viewed (geographical distribution)

Total article views: 335 (including HTML, PDF, and XML) Thereof 335 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 16 Sep 2021
Download
Short summary
An all-sky camera is used to obtain the relative sky radiance, and this radiance is used as input in an inversion code to obtain aerosol properties. This paper is really interesting since it pushes forward the use and capability of sky cameras for more advance science purposes. Enhanced aerosol properties can be retrieved with accuracy using only a sky camera, but synergy with other instruments providing aerosol optical depth could even increase the powerfull of these low-cost instruments.