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Abstract Are you a snow aficionado? What atmospheric conditions produce light, powdery snow, and what conditions produce heavy, wet snow? This project shows you how to use data from daily balloon soundings of the atmosphere and your own snow measurements to find out.Objective The goal of this project is to investigate the effect of atmospheric temperature on snowfall depth. Introduction If you're lucky enough to live in a place that gets snow in winter, you know that the feel of the snow can vary a lot. Sometimes it can be light and fluffy, and other times heavy and wet. The light, fluffy snow has less water content than the heavy snow. What accounts for these differences? One possibility might be the temperature of atmosphere in the clouds where the snow forms. Another possibility might be the temperature of the atmosphere through which the snow falls on its way to the ground. You may be wondering, "How in the world am I going to measure the temperature of the clouds?" Fortunately, you don't have to make the measurements yourself. The National Oceanic and Atmospheric Administration (NOAA) has already done it for you. Twice a day all over the U.S., weather balloons are used to take atmospheric soundings. The data from these soundings is available online (Unisys Corp., 2005). Figure 1 shows an example of an upper air sounding plot. This is a standard graph used by meteorologists to analyze data from a balloon sounding. There is a lot of additional information in the graph, but basically it is a plot of temperature (x-axis) vs. height (y-axis). The white data line on the left shows the dewpoint vs. pressure, and the white data line on the right shows the temperature vs. pressure. The pressure (in millibars, mb) is shown on the y-axis in blue lettering, and the height (in m) is shown in white lettering. A sounding plot is also called a "Skew T" plot, because the temperature axis is plotted at an angle (i.e., skew) of 45°. The temperature lines of the Skew T are in blue (at 45°).
Atmospheric pressure decreases with height above the Earth's surface. The higher you go, the less atmosphere remains above you, so the pressure decreases. "Meteorology uses pressure as the vertical coordinate and not height. This works out better for thermodynamic computations that are done on a regular basis. Pressure decreases in the atmosphere exponentially as height increases reaching 0 pressure in space. The standard unit of pressure is millibars (mb or hectopascals-hPa) of which sea level is around 1015 mb. Here is a table of pressure levels and approximate heights (Unisys Corp., 2001):"
Figure 2 shows how to read the temperature at a chosen pressure level (height). On the y-axis, find the pressure level (in mb) where you want to know the temperature. Follow the horizontal pressure line over until it intersects with the temperature plot (right-hand data plot, in white). Then follow the 45° temperature line down and to the left to the temperature axis. In the example below, the temperature at 700 mb was about −11°C.
There is a lot more information in the sounding plot, but it isn't important for this project. If you want to learn more about sounding plots, see the references in the Bibliography section. In this project you will use atmospheric sounding data combined with your own measurements of the snow depth to liquid ratio to find out if there is a relationship between atmospheric temperature and snow quality. Terms, Concepts, and Questions to Start Background Research To do this project, you should do research that enables you to understand the following terms and concepts:
Questions
Bibliography
Materials and Equipment To do this experiment you will need the following materials and equipment:
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If you like this project, you might enjoy exploring related careers.
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Meterologist The atmosphere is a blanket of gases, surrounding Earth, that creates our weather. Meteorologists study the measurements and motion of the atmosphere, and changing events within it, so that they can predict the weather. This weather forecasting helps the general public and people who work in industries such as shipping, air transportation, agriculture, fishing, forestry, and water and power better plan for the weather, and reduce human and economic losses. |
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Remote Sensing Scientist or Technologist Have you ever climbed up high in a tree and then looked at your surroundings? You can learn a lot about your neighborhood by looking down on it. You can see who has a garden, who has a pool, who needs to water their plants, and how your neighbors live. Remote sensing scientists or technologists do a similar thing, except on a larger scale. These professionals apply the principles and methods of remote sensing (using sensors) to analyze data and solve regional, national, and global problems in areas such as natural resource management, urban planning, and climate and weather prediction. Because remote sensing scientists or technologists use a variety of tools, including radio detection and ranging (radar) and light detection and ranging (lidar), to collect data and then store the data in databases, they must be familiar with several different kinds of technologies. | |
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