Current atmospheric models used to predict the times of sunrise and sunset have an error of up to four minutes at mid-latitudes (0° - 55° N/S).1 At higher latitudes, slight changes in refraction may cause significant discrepancies, including determining even whether the Sun appears to rise or set. While different components of refraction are known, how they affect predictions of sunrise/set has not yet been quantified.2 A better understanding of the contributions from temperature profile, pressure, humidity, and aerosols, could significantly improve the standard prediction.3
Because sunrise/set times and meteorological data from multiple locations will be necessary for a thorough investigation of the problem, we will collect this data using smartphones as part of a citizen science project. This analysis will lead to more complete models that will provide more accurate times for navigators and outdoorsman alike.
If you have questions about the project, feel free to email us at riseset-l@mtu.edu.