Part 4—Explore Additional NEO Data

Step 1 – Select & Display a Map of Snow Cover

Use the same procedure as in Step 1 of Part 2 to go to the NASA Earth Observations (NEO) website and display the Land Dataset, Snow Cover (MODIS) image for January 1, 2009 to February 1, 2009. Click on the Land tab under the map and select the Snow Cover (MODIS) dataset.
Note: Be sure you have selected "Snow Cover (MODIS)" and NOT the "Snow Cover & Sea Ice Extent" dataset.

Click on the Land tab and then select the Snow Cover (MODIS) dataset.
select snow cover modis

Click the image to view a larger version in a new window.
Jan 1 snow cover iamge

Step 2 – Find Out About the Snow Cover Dataset

  1. Examine the January 1, 2009 to February 1, 2009 image.
  2. Satellites can detect snow cover due to its high amount of reflectivity. Areas with higher snow cover are "brighter." In the NEO images, the amount of snow is given as a percentage of cover. 100% cover would mean areas with no bare patches. In areas with 50% cover, half of the ground is covered with snow while the other half is vegetation or soil, both of which are less reflective.

  3. Click About this dataset to learn more details about what the map is showing.
    about this data set button snow cover
  4. When the text box opens, choose the intermediate level, by clicking more detail. Use the information in the text box to answer the following questions about the data set:
    • Why is snow important (beyond it is fun to play in)?
    • What percentage of light is reflected by snow vs. bare ground?
    • What influence might this have on the Earth's energy balance?
    • Snow is a key source of water for the Earth. It provides water for drinking and for crops. Snow typically reflects 80% or more of the sunlight that falls onto it. Bare Earth only reflects 5-40% of the sunlight. Because it is highly reflective, snow plays an important role in the Earth's energy balance. Without snow and ice, Earth's surface temperature would be higher.

Step 3 – Explore How Snow Cover Changes over the Course of A Year

Before you begin, create a Snow Cover folder to hold the twelve images you will download.
  1. Go to the NASA Earth Observations (NEO) website and download the Snow Cover (MODIS) January 1, 2009 to February 1, 2009 image at a resolution of 0.5 degrees and save it as 01_snowcover.jpg. Repeat the process for all twelve months of 2009 until you end up with a total of twelve images, named from 01_snowcover.jpg to 12_snowcover.jpg.
  2. If you need help downloading the images, follow the same procedure as in Part 2, Step 3.
  3. To animate the Snow Cover images using ImageJ, follow the same procedure as in Part 3 with the Reflected Shortwave Radiation images.
  4. If you had difficulty creating or saving the stack, then use the Snow Cover stack (Snow.tif) provided in the link below. To download and save the Snow Cover stack, on a PC, right-click on the link and on a Mac, control-click on the link. Then choose File > Save As... and navigate to where you want to save the stack.

    Snow.tif (TIFF 8.9MB Jan13 10)

  5. Experiment with changing the speed of the animation. Step through or animate the Snow Cover images from January 2009 through December 2009. Carefully observe the changes that occur during the year and then answer the following questions:
    • What regions of the Earth are the most snow covered each month?
    • How does this change in relationship to the seasons?
    • Which months of the year have the largest area of snow cover in the Arctic regions of Canada and Siberia, Russia?
    • The Northern Hemisphere is the most snow covered region on Earth during the months of December to February. However, snow cover follows seasonal patterns. From June through August, snow cover in the Southern Hemisphere increases, especially in places of high elevation like the Andes Mountains. In general, winters are less harsh and there is less snow cover in the Southern Hemisphere when compared to the Northern Hemisphere. This is because the Northern Hemisphere has more of its area covered by land masses. Additionally, snow cover in the Southern Hemisphere is influenced by the moderating affect of the oceans. The largest snow cover in the Arctic regions of Canada and Siberia occurs during the months of December through February.

Step 4 – Select & Display a Map of Land Surface Temperature

Use the same procedure as in Step 1 of Part 2 to go to the NASA Earth Observations (NEO) Web site and display the Land Dataset, Land Surface Temperature (Day) (MODIS) image for January 1, 2009 to February 1, 2009. click on the Land tab under the map and select the Land Surface Temperature (Day) (MODIS) dataset.
Note: Check your selection carefully as there are three other Land Surface Temperature datasets besides this one.

Click on the Land tab and then select the Land Surface Temperature (Day) (MODIS) dataset.

land surface temperature map selected

Click the image to view a larger version in a new window.
jan land surface selected

Step 5 – Find Out About the Land Surface Temperature (Day) (MODIS) Dataset

  1. Examine the January 1, 2009 to February 1, 2009 image.
  2. Imagine a summer evening while you are walking barefoot on a warm sidewalk, sandy beach, or pool deck. That warmth that you feel in your feet, came from the Sun's rays shining on Earth during the day and warming its surface. Some surfaces hold that warmth longer than others. Can you think of a place that is always cool on a summer day? A grassy lawn would be one example. Satellites can detect the temperatures of these surfaces on the Earth. Some areas change temperatures dramatically over the course of a year.

  3. Click About this dataset to learn more details about what the map is showing.
    about this data set button
  4. When the text box opens, choose the intermediate level, by clicking more detail. Use the information in the text box to answer the following questions about the data set:
    • How is land surface temperature different than surface air temperature?
    • Why do scientists monitor land surface temperature?
    • Land surface temperature is measured at the surface of the Earth, directly on the surface material whereas surface air temperature is measured at a height of one to two meters above the ground. Surfaces on Earth heat and cool differently. It is important to monitor them in order to predict weather and climate.

Step 6 – Explore How Land Surface Temperature (Day) (MODIS) Changes over the Course of A Year

Before you begin, create a Land Surface folder to hold the twelve images you will download.
  1. Go to the NASA Earth Observations (NEO) website and download the Land Surface Temperature (Day) (MODIS) January 1, 2009 to February 1, 2009 image at a resolution of 0.5 degrees and save it as 01_landsurface.jpg. Repeat the process for all twelve months of 2009 until you end up with a total of twelve images, named from 01_landsurface.jpg to 12_landsurface.jpg.
  2. If you need help downloading the images, follow the same procedure as in Part 2, Step 3.
  3. To animate the Land Surface images using ImageJ, follow the same procedure as in Part 3 with the Reflected Shortwave Radiation images.
  4. If you had difficulty creating or saving the stack, then use the Land Temperature stack (Landtemp.tif) provided in the link below. To download and save the Land Temperature stack, on a PC, right-click on the link and on a Mac, control-click on the link. Then choose File > Save As... and navigate to where you want to save the stack.

    Landtemp.tif (TIFF 8.9MB Jan13 10)

  5. Experiment with changing the speed of the animation. Step through or animate the Land Surface Temperature (Day) images from January 2009 through December 2009. Carefully observe the changes that occur during the year and then answer the following questions:
    • What regions of the Earth are the warmest each month?
    • How does this change in relationship to the seasons?
    • Land surface temperature warms and cools as the seasons change on Earth. As the incoming solar radiation increases in the spring and summer months, the temperature generally increases. However, the warming in the spring is delayed in snow covered areas, because the snow reflects a large percentage of the incoming solar radiation back out to space.

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