AP Physics
5 June 2011
Project Analysis
In our project, “How Permanent is Permafrost?” we used Google Earth and Microsoft Excel to explore the area around Chersky, Russia. More specifically, we examined the presence of permafrost, which is soil that has a sub-zero temperature for two or more consecutive years. Permafrost is found primarily in the Northern Hemisphere, including in the area surrounding Chersky, but it regularly melts and freezes depending on the season. Permafrost is an important thing to study because trapped in it is frozen dead plant and animal matter. As the permafrost thaws, this matter decays, releasing gases such as carbon dioxide and methane, which contributes to global warming, as they are greenhouse gases. Additionally, the melting of permafrost can change the landscape of a region and even affect the infrastructure that is built upon it – without a stable base, buildings and bridges are liable to crack and fall apart (pictures of this occurrence were seen when exploring photos of the region in Google Earth). As a result, many scientists study the temperature of permafrost so that they can better understand and, hopefully, learn to prevent this issue.
Using Google Earth, we became familiar with the area around Chersky, such as the types of permafrost that surround it and the distance the different borehole sites are from the town. It was discovered that Chersky is primarily surrounded by continuous permafrost, which is defined as an area where permafrost makes up more than 90 of the soil. We were then presented with data to graph and analyze, gained by drilling boreholes into the soil. This data included the temperatures 0.8 and 3.2 meters below the surface of the permafrost and, for some locations, the above-surface temperatures, both in January and July. The data indicates that in January, temperatures above the surface were lower than the temperatures 0.8m below the surface, which were lower than the temperatures 3.2 m below the surface. This makes sense, since the permafrost has retained heat from the warmer seasons that precede January – the permafrost closer to the surface is more likely to lose heat, so it is lower in temperature. The opposite occurred in July – the deeper into the ground, the lower the temperature, as the permafrost on top of this layer acts like insulation for the lower layers – most of the heat that penetrates the permafrost affects that upper layer. This relates to the concepts of thermodynamics that we learned in physics we have learned, including the formula for the rate of heat transfer, which involves the thickness of the object (H = kA∆T/L). For all but one of the data sets, the surface temperature in both January and July has risen over the years, possibly an indication of global warming. The temperature changes within the permafrost were relatively small - slopes of the regression lines only had orders of magnitude in hundredths of degrees Celsius per year and were (seemingly randomly) positive or negative. Overall, the data simply confirms pre-established theories such as global warming and the equations and concepts of thermodynamics.