June 28, 2017
Ethan Siegel wrote an outstanding piece in Forbes this week about seven things to anticipate during the total eclipse on August 21st, 2017. One of the points that Siegel made is that many people will experience a noticeable temperature drop. The peer-review scientific literature reveals other meteorological impacts of solar eclipses too (mainly wind) so as an atmospheric sciences professor and meteorologist, I thought that it would be interesting to point out four cool weather activities that you and the kids can do for the upcoming eclipse.
Images from the Hinode spacecraft showing a type of solar eclipse
Track the temperature changes. Siegel does an excellent job explaining what happens when 80 to 99 percent of the sun is essentially “blocked. He writes:
sunlight reaching Earth outputs a total of approximately 700 Watts-per-square-meter in the infrared, where human skin is sensitive. By comparison, a fully overcast sky might block only about 65-70% of the heat from the Sun, something your skin will definitely notice. If you’ve never experienced it before, the lack of heat coming from the Sun can feel both surprising and disturbing. Prepare for this the same way you’d prepare for sundown; temperatures may drop by as much as 20-to-30 degrees Fahrenheit in some places over the course of an hour or two.
There is an awesome opportunity for all of us to scratch our “weather geek” itch even during the eclipse. The data below shows how temperature changed in Lusaka, Zambia during an eclipse on June 21, 2001. NASA Astronomer Mitzi Adams used a Thermochron Temperature Logger to make these measurements but you do not need to be a rocket scientist to make your own measurements. You can also track temperatures with
- An “old school” mercury thermometer
- A hand-held weather station (This link provides an overview of some of the more popular ones)
- Your phone or a weather app (However, make sure the app is providing temperature for your actual geographic location
- A personal weather station.
Changes in temperature during a 2001 eclipse over Lusaka, Zambia.
You might consider taking your measurements roughly every 10 minutes or so (starting an hour before the eclipse and continuing an hour after the eclipse). Record your temperature readings and times so that you can graph the results. For maximum accuracy, you might even consider groups of measurements at each observation time and taking the average of the group at each time.
Monitor how other meteorological variables change and sky conditions change. If you are using a weather station, it would also be interesting to observe how (or if) pressure, humidity, or wind is affected. To do this, simply add these measurements to the same data chart that you are tracking for temperature. If you do not have access to a weather station, there are several weather stations that you can view online such as Weather Underground, WeatherBug, and WeatherSTEM. The picture below reveals the weather conditions at the University of Georgia from our WeatherSTEM unit. WeatherSTEM CEO and meteorologist Edward Mansouri said in an email
Three of WeatherSTEM’s college football stadium weather stations are in the direct path of the August 21st total solar eclipse including Clemson University, Vanderbilt University, and Western Kentucky University. Others like the University of Georgia are very close. We will be showcasing in real-time the changes in key meteorological variables that take place during all phases of the eclipse including total solar radiation, temperature, humidity, and wind. I will be watching this once-in-a-lifetime spectacle from Clemson University’s Memorial Stadium
You might also notice sky conditions in the picture. I cannot wait to look back at the UGA WeatherSTEM “sky video” during the eclipse (These things are awesome to look at on any weather day so find one and explore it).
Weather and sky conditions at University of Georgia Geography-Geology building from the WeatherSTEM weather station and sky camera.
Assess the likelihood of cloudiness from your viewing location. Even if it ends up being cloudy at your viewing location, the “weirdness” of darkness in the middle of the day is awe-inspiring and humbling. Jared Rennie is a scientist at the Cooperative Institute for Climate and Satellites-North Carolina (CICS-NC). In conjunction with NOAA’s National Centers for Environment Information, Rennie developed a cloud climatology to provide guidance on the likelihood of cloudiness on August 21st. It is apparent that cloudiness is more likely east of the Mississippi River. You can use the CICS-NC Interactive Map to see what the viewable percentage is for your location by following this link. It is important to keep in mind that these are just percentage “estimates” for cloudiness not “guarantees.”
Average historical cloudiness on August 21 in the continental United States
Determine what the eclipse looks like from the vantage-point of a weather satellite. Most meteorologists know that there are some amazing satellites in orbit monitoring the weather. NOAA’s GOES-16 is a game-changing piece of technology that is revolutionizing how we monitor the weather. It will be intriguing to view the United States from the perspective of GOES-16 and other satellites during the eclipse. The website www.eclipse2017.org is a great resource for all things related to the eclipse, and they have included links for weather satellite observations.
The shadow of the total solar eclipse (March 9th, 2016) as seen by a geostationary weather satellite, JMA Himawari-8
This is clearly going to be a moment for the solar and astronomy enthusiasts, but there is definitely some cool factor for weather enthusiasts too. My colleague Dr. John Knox had the vision for an interactive viewing experience. This vision has become a reality so I will be joining thousands of University of Georgia students, faculty, and friends in iconic Sanford Stadium for “the blackout between the hedges.”
Where will you be? And be sure to wear certified protective eyewear no matter wear you are.