Print: Frozen Symmetry

“Frozen Symmetry

A cottonwood reflects on itself in a frozen farm pond during an intense sunset

The Grass is Greener…

Nature photography often plays “tricks” with me. Perhaps this is to teach me lessons about the bigger picture, about life?

One lesson that keeps coming up for me in my photography pursuits has a theme related to “The Grass is Always Greener on the Other Side of the Fence…” proverb.

I live in a beautiful area of Northern New Mexico, between Santa Fe and Taos, off of the “High Road to Taos.” This scenic route is a destination for many that want to see and experience the natural beauty and cultures of the Sangre de Cristo mountains. Beautiful light and compositions abound here on any given day. I try to photograph the sunrise and sunset every day when I am at home and not on the road.

Maybe I was getting tired of the same old scenery and needed to see some new landscapes? To quench my wanderlust and desire for exciting photographic opportunities, I packed up my truck and drove to the Tetons and Yellowstone in mid-December.

New Mexico had another dry and warm winter that year. The skiing at home was bleak. Changing that up for the deep snow and cold winter in Northwest Wyoming was my goal of this road trip.

Wolves, bison, foxes, bighorn sheep, and amazing alpine lighting on the Tetons were good highlights for this winter road trip. Satisfied with my nature photography exploits on my trip up north, I made the long venture home. Driving my old, yet trusty, truck for hundreds of miles on icy roads, through snowstorms and next to big rigs on the interstates was taxing on me.

By the time I got close to home, it was almost dark. Northern New Mexico welcomed me with deep and vibrant colors in the sky. I had taken enough photos on this trip, though, and all I wanted to do was get home and take a hot shower. As I drove slowly past a familiar pond, bright red and cold blues of the sky reflected off the ice and meltwater. I kept driving. I did not “need” any more photographs.

After passing the pond, that little voice inside my head spoke up. “What are you doing? That is an amazing scene, your camera, and tripod are on the seat next to you. Go back and photograph that!”.

Backing my truck up to the pond and looking through my viewfinder at the pond, a stunning reflection of a stately cottonwood tree, stark and bare of leaves, was precisely displayed in this frozen mirror. It was still and cold. In the ice and cold water, I could see every little branch of the tree.

My “lesson” for this trip showed me that this photograph was the best of a two-week winter road trip. The trip was a great experience, and that is what life for me is all about, experience first. The photos I created on the road trip were worthy. Ironically, the best photograph, in my view, was taken within a mile of home, when I returned to my place.

Shiny Ice

As I photographed the reflection of the tree in the partially frozen pond, it was hard to differentiate the light reflected from ice with light reflected from water.

Since ice is frozen water, wouldn’t ice and water reflect the same amount of light? Not really. Ice has a slightly lower index of refraction (n_ice = 1.31) than water (n_water = 1.33). The index of refraction of a substance is the ratio of the speed of light in a vacuum to the speed of light in that substance.

The reflectance of light from a material surface depends on the index of refraction of that material. The slightly lower refractive index of ice results in less reflection from ice as compared with reflection from a liquid water surface. At normal incidence, both water and ice reflect about 5% of the light incident.

Generally, water has a smoother surface than ice. Light reflecting from water reflects from only one surface. Light that doesn’t reflect from the water surface propagates into the water, where it is eventually absorbed and converted to heat.

Ice often has some snow on its surface. Snow is made up of small ice crystals with air gaps between them. Light falling onto snow may be reflected at the first surface, but any light that isn’t reflected will meet lots more ice/air interfaces as it travels through the snow, and at every surface, more light will be reflected. The result is that much more light is reflected from snow than from water. You can see this when you look at a snowy scene with an unfrozen body of water surrounded by snow. Sunlight reflecting from the snow surface is much brighter than that reflected from the body of water.

The amount of sunlight reflected from snow and ice is crucial in climate change. The albedo of a surface is a measure, ranging from [0,1], of how much sunlight reflects from it. A low albedo surface does not reflect as much sunlight as a surface with a high albedo.

Sea ice has a much higher albedo compared to other earth surfaces. A typical ocean albedo is approximately 0.05, while bare sea ice varies from about 0.5 to 0.7. The ocean only reflects about 5% of the sunlight incident on it. The ocean absorbs most of the energy from sunlight.

Sea ice, with a much higher albedo than water, reflects 50 to 70 percent of the incoming energy. The sea ice absorbs less solar energy and keeps the surface cooler.

Snow has an even higher albedo (0.9) than sea ice. Sea ice covered with snow reflects about 90 percent of the incoming solar energy. Snow insulates the sea ice below it.

Once the snow on top of sea ice begins to melt, a cascading effect begins. Meltwater from snow on top of ice has a lower albedo than the unmelted snow. Melt ponds gain more energy from sunlight relative to the surrounding snow, which accelerates more melting of the surrounding snow and a positive feedback loop.

The more the snow on top of the ice melts, the more ice melts, absorbing more and more solar radiation, warming the Earth more and more.

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