Extended Data Fig. 1: Benchmarking of daylight intensity measurements at 10 m with published measurements and calculations.

The units from our data are in each case converted and plotted corresponding to the units and type of plot used in the respective compared publication. (a) Nightlight data measured for individual wavelengths between August 24–25, 1999¹⁰⁰. (b,c) Analysis from (a) performed on natural light data measurement for August 24–25 2010. (c): saturation and noise-equivalent irradiance thresholds are indicated 400 nm (pink line), 500 nm (green line) and 700 nm (red line). (d) Calculations of light irradiance at different ocean depths¹⁰¹. Black arrow points at UVA spectral range clearly present at 10 m water depth and below. (e,f) Our measurements from July 4, 2011 and August 24, 2010 at 12:00 noon for comparison. (g) Irradiance data calculated for different water depths based on in situ measurements of the attenuation coefficients in coastal waters in Corsica using a PhotoreSearch PR-670 spectrophotometer in a custom UW housing on July 4th, 2010, under bright sun at noon¹⁰². (h,i) Our measurements from July 4, 2011 at 12:00 noon timepoint. (j) Irradiance in atmosphere and in water at different depths¹⁰³. (k,l) Representative daylight measurements from July 4, 2011 and August 24, 2010 at 12:00 noon timepoint from our 10 m measurement set for comparsion. (m,n) Average spectral irradiance and individual wavelength penetration under different ocean depths¹⁰⁴. (f,i,l) Examplary saturation and noise equivalent irradiance (NEI) levels of the RAMSES hyperspectral radiometer indicated as dots. Panel a reproduced with permission from ref. ¹⁰⁰, Springer Nature Ltd; d reproduced with permission from ref. ¹⁰¹, Cambridge University Press; g reproduced with permission from ref. ¹⁰², Elsevier; j reproduced with permission from ref. ⁶⁶, Mary Ann Liebert, Inc.; m and n reproduced with permission from ref. ¹⁰⁴, Oxford University Press.