Because of the Sun

South Dakota Discovery Center Special Projects Director and 2017 National Geographic Grosvenor Teacher Fellow Anne Lewis has recently returned from an expedition to Svalbard, Greenland and Iceland.

This is the second in a series of blog posts from her about the expedition.

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I decided to do field work using GLOBE protocols. on my Grosvenor Teacher Fellowship because 1) that is what one does on an expedition according to every movie I’ve ever seen and 2) field work was a natural way to connect the Arctic and my teaching. My plan was and is to compare and contrast results from the Arctic field studies with results from Prairie field studies.

Selecting the field work protocols necessitated some thought, balancing equipment requirements, luggage space and a host of other variables, some of which I discovered only after I got to the Arctic. For example, I was in polar bear country and that meant I couldn’t go marching off on my own to set up transects. I had to adapt.

I used an infrared thermometer to take surface temperature readings.

The protocol that rose to the top of the suite I selected was surface temperature. I wasn’t expecting this to be the protocol but then there was a lot I didn’t expect about the Arctic. In retrospect, it made sense. The Sun more than any other factor is what makes the Polar region unique.

The Arctic in early July has a lot of sun. And what I mean by “has a lot of sun” is the sun did not set. Ever. It was 24 hours of daylight.  (See What is a Solstice for an explanation). Even the clouds couldn’t darken the sky to twilight let alone night levels of black. I found this 24 hour sunlight invigorating yet disorienting, a whole blog post in and of itself.

This constant sunlight meant that there was nonstop solar energy coming into the Arctic. Some of it, to be sure, was filtered out by clouds, but even on the cloudiest day Sun energy still got through.

We all know the Sun warms the Earth. We learn this as children, sometimes painfully after stepping barefoot on blacktop on a hot summer’s day. Yet while we know what happens, many of us cannot explain why. Allow me to digress a moment.

Copyright Kaitlin Naughten. Use by http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
Energy from the Sun warms the Earth and is radiated off as heat. Copyright Kaitlin Naughten. Used under Creative Commons license.

When a photon of energy from the sun hits the Earth’s surface, the surface will absorb some of the energy and reflect the rest. This absorption heats up the surface, a little or lot depending on several factors including the height of the sun in the sky (more about that in a bit) and the color of the surface with darker colors generally heating up more than lighter.

Eventually, though, the surface will release the absorbed energy, radiating it off as heat. Since this radiation happens 360° some of the heat is radiated downwards warming below the surface, some of it sideways, and some of it upwards warming the air above the surface. Some of that heat radiated into the air will make its way back to space as long as it’s not reabsorbed along the way.

On the hottest days on the Prairie which are also among the longest we wait for the relief of sundown to stop the constant barrage of incoming Sun energy so the Earth can cool down, radiating the heat back out to space. We didn’t have this sundown relief in the Arctic but then, we didn’t need it because the sun never got very high in the sky. It’s not just the length of days (i.e. how long the sun shines) that heats the Earth; it’s also the angle of the rays. A sun lower in the sky means the rays are less direct and therefore less intense.

A lower sun altitude means less intense solar energy.

On the summer solstice in Longyearbyen in Svalbard which is well above the Arctic circle, the sun only reached an altitude of 35° at solar noon, the point when it is at its highest and therefore the most direct. Compare this with a sun altitude of 69° at solar noon in my home city of Pierre, SD on the same date. We have to wait to later in October to have a 35° sun altitude at solar noon.

In measuring surface temperature, I was measuring the impact of the constant, though somewhat indirect energy on the Earth’s surface.

Selecting surface temperature as a protocol was a serendipitous choice as I discovered I could use it on land and at sea where I measured the temperature of ice and ocean. The procedure was different at sea since I had to take the reading off the side of the ship, a height of maybe 10 meters above the surface. On land I took the reading about 1.2 meters off the ground. This meant the two data sets weren’t comparable to each other but no matter.

Land and sea each had their own story to tell.

On land, the coldest surfaces were ice and snow. The warmest was dark sand, warmer than similarly colored rock even. Interestingly, plants-all low growing, a mixture of forbs and mosses–could be warmer or cooler than the nearby barren surfaces. I can think of several possible explanations but I would like data with more tightly controlled variables before I put my ideas out for public consumption. In science, you quickly learn there is almost never enough data.

This Svalbard Poppy was warmer than the surrounding rock.

One forb that was warmer than its surrounding rock was the Svalbard Poppy. This national flower of Svalbard holds the altitude record for flowering plants and indeed, we did see it on a gravelly ridge, well above sea level. The day was raw and gray, with squalls of icy flurries which settled on the plants. The flowers bloomed individually and in small groups. I counted 5 blooms in one cluster, a dot of life and color in an otherwise gray, brown and white landscape. This is the plant that was more than ¾ a degree Celsius warmer than the surrounding rock.

Sea ice and open ocean. The open ocean measured under sunny conditions–not shown- here-radiated more heat than the ice did.

At sea, I took temperatures of the surface, aiming my thermometer at both the dark open sea and the blue/white ice. The range of their temperatures overlapped–the highest ice temperatures were about the same as the lowest sea temperatures–but overall the open sea was warmer than the ice.

It did not come as a surprise that the dark sea radiated more heat than ice. More radiant heat results in a warmer atmosphere which melts ice and exposing more dark ocean surface. You can see where this is going. It was both sobering and compelling to see those final numbers in my spreadsheet. Somehow, the impact is different when it’s your own data.

I am still organizing and processing my experiences on the Lindblad expedition. My vision for how I want to use these experiences in my teaching is bolder after the expedition than before. My big dream is to develop a cross curricular unit (science, geography, literature, writing, math) that can be adapted to multiple grade bands with the Polar setting as the anchor. I don’t know where this will end. But I do know where it will begin.

With the sun.