Figure 1.

The spatial distribution of artificial light at night across Plymouth Sound and the Tamar Estuary, UK in cloudy conditions (5–8 Okta). Modelled scalar irradiances (µW m⁻²) are given for Blue (400-500 nm, A–D), Green (495–560 nm, E–H), and Red (620-740 nm, I–L) light on the seabed during Mean High Water Spring (MHWS) tide (A,E,I), Mean Low Water Spring (MLWS) tide (B,F,J), and immediately beneath the water surface (C,G,K). Measured planar irradiances are given for light incident on the sea surface (D,H,L). The coordinate reference system is OSGB 1936/British National Grid. Land is given by solid grey regions, the survey extent by dashed grey lines. Maps created in QGIS v3.4 (https://qgis.org).