Preprints
https://doi.org/10.5194/amt-2020-480
https://doi.org/10.5194/amt-2020-480

  12 Feb 2021

12 Feb 2021

Review status: this preprint was under review for the journal AMT. A revision for further review has not been submitted.

An improved cloud index for estimating downwelling surface solar irradiance from various satellite imagers in the framework of a Heliosat-V method

Benoît Tournadre, Benoît Gschwind, Yves-Marie Saint-Drenan, and Philippe Blanc Benoît Tournadre et al.
  • MINES ParisTech, PSL Research University, O.I.E. - Centre Observation, Impacts, Energy, 06904 Sophia Antipolis, France

Abstract. We develop a new way to retrieve the cloud index from a large variety of satellite instruments sensitive to reflected solar radiation, embedded on geostationary as non geostationary platforms. The cloud index is a widely used proxy for the effective cloud transmissivity, also called clear-sky index. This study is in the framework of the development of the Heliosat-V method for estimating downwelling solar irradiance at the surface of the Earth (DSSI) from satellite imagery. To reach its versatility, the method uses simulations from a fast radiative transfer model to estimate overcast (cloudy) and clear-sky (cloud-free) satellite scenes of the Earth’s reflectances. Simulations consider the anisotropy of the reflectances caused by both surface and atmosphere, and are adapted to the spectral sensitivity of the sensor. The anisotropy of ground reflectances is described by a bidirectional reflectance distribution function model and external satellite-derived data. An implementation of the method is applied to the visible imagery from a Meteosat Second Generation satellite, for 11 locations where high quality in situ measurements of DSSI are available from the Baseline Surface Radiation Network. Results from our preliminary implementation of Heliosat-V and ground-based measurements show a correlation coefficient reaching 0.948, for 15-minute means of DSSI, similar to operational and corrected satellite-based data products (0.950 for HelioClim3 version 5 and 0.937 for CAMS Radiation Service).

Benoît Tournadre et al.

Status: closed (peer review stopped)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2020-480', Anonymous Referee #1, 21 Mar 2021
  • RC2: 'Comment on amt-2020-480', Anonymous Referee #2, 25 Mar 2021
  • RC3: 'Comment on amt-2020-480', Anonymous Referee #3, 27 Mar 2021

Status: closed (peer review stopped)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2020-480', Anonymous Referee #1, 21 Mar 2021
  • RC2: 'Comment on amt-2020-480', Anonymous Referee #2, 25 Mar 2021
  • RC3: 'Comment on amt-2020-480', Anonymous Referee #3, 27 Mar 2021

Benoît Tournadre et al.

Benoît Tournadre et al.

Viewed

Total article views: 407 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
292 104 11 407 4 2
  • HTML: 292
  • PDF: 104
  • XML: 11
  • Total: 407
  • BibTeX: 4
  • EndNote: 2
Views and downloads (calculated since 12 Feb 2021)
Cumulative views and downloads (calculated since 12 Feb 2021)

Viewed (geographical distribution)

Total article views: 355 (including HTML, PDF, and XML) Thereof 355 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 03 Aug 2021
Download
Short summary
Solar radiation received by the Earth's surface is a valuable information for various fields like photovoltaic industry or else climate research. Pictures taken from satellites can be used to estimate the solar radiation by identifying cloud properties of reflection. Several issues exist though: satellite sensors are all different. Even two identical instruments looking over the same place see different things. We aim at estimating solar radiation from a wide variety of such satellite sensors.