Archive for the ‘albedo’ tag
Did you take a photo of white paper on the ground June 21 for the Albedo Project?
Whether or not you participated, you can now take a look at the data at the Albedo Project website. Locations of all the photos are shown on a Google Map. Zoom in to find your data point. And if you’d like to peruse the photos of white paper, you can find them in Flickr.
Photos were sent in from over 30 US states and 11 countries, pointing out that projects like this would not happen without participation by photo-snapping volunteers!
This is “not bad for a first effort,” according to the web site. However, the resulting albedo calculated from the photos is not very accurate. Here’s the results summary from the Albedo Project website:
“The average albedo for all samples is 0.11 – That’s pretty low, but when you look at the images, you can see that it makes sense. Some of those photos are dark, and they were not adjusted in any manner. (The average albedo for Earth is about 0.3)”
Why is the number so low? The photos did not provide a full representation of the Earth’s surface. About half of the photos were taken on grass, about a third were on concrete or brick, and most of the others were on soil or sand.
Wherever you are – anywhere in the world – on June 21st consider taking and submitting a photo of a blank white piece of paper between 5:00 and 8:00 pm.
Your photo will not be just a picture of a pretty white piece of paper, it will be scientific data used to calculate earth’s albedo – the proportion of solar energy that bounces back out to space when it hits the Earth’s surface.
For three years Dr. Kathleen Gorski and her students at Wilbraham and Monson Academy near Springfield, MA have been snapping pictures of white paper and using them to measure albedo by comparing the white paper to the surrounding ground surface.
Now they are opening the project up to anyone who would like to participate!
Here’s how you can get involved:
- Stick a reminder in your calendar for Tuesday June 21, 2011 between 5:00-8:00 pm so that you don’t forget. (Note: I added this step to Kathleen’s instructions because I know I will need a reminder!)
- Put a white card (index or business cards work well) on any ground surface with the white side facing up.
- Snap a digital photo. No particular position for the camera is required. Just hold it, look down, and take the shot. (Kathleen has found that any camera will do – a cell phone or SLR will both work. And any resolution will be fine.)
- Email the photo to firstname.lastname@example.org.
- 5. Include the location (either your city and state or your latitude and longitude).
Kathleen and her students will analyze the data, comparing the response of the white card to the response of the ground surface in each photograph using ImageJ software and will depict the data points on a map. They will be posting the results this summer or fall on a new project website, and Kathleen will be presenting about the project to teachers at the National Science Teachers Association meeting in Hartford, CT in the fall.