From Watts Up With That?

[This post IS NOT an April Fool’s joke as was the previous]

by Guillermo Gonzalez

Since the 19^th century scientists have made meteorological measurements during solar eclipses (https://royalsocietypublishing.org/doi/full/10.1098/rsta.2015.0217). A total solar eclipse affords us the opportunity to measure the response of the atmosphere to a known forcing that is very different from the day-to-day hemispheric heating from sunlight superimposed on gradual seasonal changes. I made my own very small contribution to this topic during the October 24, 1995 solar eclipse in India (https://ui.adsabs.harvard.edu/abs/1997KodOB..13..151G/abstract).

One phenomenon that deserves further study is surface pressure fluctuations produced during a solar eclipse. These have been interpreted as gravity waves. They have been measured at several eclipses, though attempts are not always successful and quantitative results vary.

For examples from the literature, see (https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JD089iD03p04953?casa_token=-2NygK7STpQAAAAA:TlV1SXPo0Hlj5JdfNIbr7ZpFCgUL8xUpWCDzy0FuGraSbZPOKf2081Gy8bQ4xoSURvOxHbjEig30BcU , https://journals.ametsoc.org/view/journals/atsc/70/3/jas-d-12-091.1.xml?tab_body=abstract-display , https://royalsocietypublishing.org/doi/full/10.1098/rsta.2015.0217 , https://royalsocietypublishing.org/doi/full/10.1098/rsta.2015.0222).

There are a couple reasons published studies of eclipse gravity pressure waves have often had inconclusive results. First, usually only a few instruments have been deployed along the eclipse track. Second, local meteorological changes unrelated to the eclipse (such as a passing front or atmospheric tides) have masked the eclipse waves.

This deficiency can be overcome by deploying many instruments along the path of totality. Sounds like an expensive experiment. It can be done very cheaply with modern technology. Many phones have built-in pressure sensors. They also have built-in GPS sensors, providing accurate locations and times. Phones have multiple additional sensors, making them handy portable scientific data loggers.

My purpose in writing this short post is to encourage as many people as possible to use their phones to gather data during the April 8 solar eclipse with multiple sensors.

The Sensor Logger phone app (https://github.com/tszheichoi/awesome-sensor-logger , https://www.tszheichoi.com/sensorlogger ) can record and store the readings from any combination of your phone’s sensors. I’ve setup a crowd sourced solar eclipse experiment with Sensor Logger. You can join the experiment one of two ways:

1 – Go to https://sensor.tszheichoi.com/app/study/eclipse1 with the browser on your phone and follow the directions to join the experiment. The ID of the experiment is ‘eclipse1’.

2 – Download the Sensor Logger phone app. Then, scan the following QR code with your phone camera and follow the directions:

On April 8 you should be within or near the path of totality to participate in the experiment, but measurements might still be useful even if you’re hundreds of miles from it. Place your phone face up somewhere outside where it will be undisturbed for at least several hours. It should be fully charged at the start of the experiment or plugged into a power source. Start recording data about 3 hours before the predicted time of mid-eclipse at your location and end your recording 4 or 5 hours later. NOTE: your location will be recorded along with light level, magnetometer, sound level, and barometric pressure. If you have the opportunity, also record data 24 hours before and/or after. Your data will be stored by the app on the cloud.

I will collect the data from the cloud and analyze it. Hopefully, I will publish the results in a scientific paper some months later.

Bio: Guillermo Gonzalez is an astronomer who lives in northern Alabama and works for Tellus1 Scientific, LLC. He obtained his Ph.D. in astronomy in 1993 at the University of Washington. He has published over 90 research papers in astronomy and astrophysics journals.