The ring is the year, starting at the December solstice at the top and running clockwise. Each band is one voice, North Pole outermost; its colour is that place's day length, from polar night (deep blue) to polar day (gold). The bands light up as the year plays.
The bar is the meridian itself. Each parallel glows while its voice sounds. The sun marker rides between the tropics: it is the latitude where the sun stands overhead at noon, and the reason for everything you hear.
Tap or hover a parallel, or its band in the ring, to see its whole year of daylight; tap it again to let go.
The numbers beside the bar are that day at each parallel: day length, and sunrise and sunset in local solar time (noon is 12:00 everywhere on the line). Everything here is calculated from the sun's geometry (D, derived); later layers will add measured weather, ocean and ice.
Layer 2 adds air, sea and ice, each on its own instrument so the chorus has room. The sung voice still carries the light. The organ is the air: on a cold day it plays one dark rank; on a warm day it adds the octave rank and opens up. A warm night also breathes fuller. The strings are the sea, an octave under each ocean parallel, heard day and night because the ocean doesn't sleep; warmer water sounds fuller. Sea ice is a lid on the sea voice, quieting it, and a high glass shimmer as loud as the ice is dense. The buttons recolour the ring by each layer. Air temperature is ERA5 reanalysis (D, modelled; Copernicus, CC BY 4.0, via Open-Meteo); sea surface temperature is NOAA OISST v2.1 (R); sea ice is the NOAA/NSIDC Climate Data Record v6 (R). Each value is the mean over the breath's block of days, at the grid cell nearest the parallel.
Places and territory. The land and ice voices stand on Inuit Nunangat (75°N), at the Nunavut–Manitoba boundary (60°N), in South Dakota (45°N), on the Edwards Plateau in Texas (30°N), and in Antarctica (75°S and 90°S). Acknowledgements of the peoples whose lands these are, in their own words where they publish them, are being prepared and will be added here.
Sources. Daylight is calculated from solar geometry (Meeus, as in NOAA's solar calculator; checked against the JPL DE421 ephemeris). Air temperature: ERA5 reanalysis (Copernicus Climate Change Service, CC BY 4.0), via the Open-Meteo historical weather API. Sea surface temperature: NOAA OISST v2.1 (Reynolds et al. 2007; Huang et al. 2020), via NOAA CoastWatch ERDDAP. Sea ice: NOAA/NSIDC Sea Ice Concentration Climate Data Record, version 6, via NOAA CoastWatch ERDDAP. Each value is the mean over a breath's days at the grid cell nearest the parallel; the cell used and its distance are recorded in data/meridian/. The South Pole's air temperature is ERA5 standing in for the Amundsen–Scott station record. The audio is licensed CC BY 4.0.