The questions below are based on the following products. View and compare them by selecting a different image for each radio button. Note that the imagery and products are no longer labeled for you. This means you will have to differentiate the imagery from each other before moving through the exercise for most effective learning. Write down which option number is which product for reference along the way.
What time of day are the images from?
The correct answer is a.
The small amount of dark in the bottom left (western) corner of the visible and natural colour products tells us that it’s dawn.
What month do you think it is in these images?
The correct answer is c.
Based on the slope of the terminator, the sun is north of the equator. This means the Northern Hemisphere is in the summer month of August.
Since these products are from a summer morning, the low clouds in the night microphysics RGB should be:
The correct answer is b.
During the warm season and warm weather regimes, low clouds are light blue-grey. They are only light green during the cold season and cold weather regimes.
View the night microphysics RGB and look at the low clouds. Why are they both light blue and light green?
The correct answers are b, c.
The height of the clouds and their latitudinal differences make them look different.
The cloud tops are warmer in the southern portion of the image so they are likely lower. However, since the thickness of the troposphere is markedly different in the northern and southern portions of the image, it is impossible to truly compare the cloud heights without more information, say, from soundings.
The closer to the equator you get, the less clouds look like “winter” low clouds on RGB imagery unless there is a climatological anomaly in the area.
There are generally two heights of clouds off the western coast of Africa from Liberia to Senegal. Which product could you use to identify their cloud-top height differences?
The correct answers are b, c, d, e, and f.
The most effective products to use are the infrared channels and the night microphysics product. The water vapour, dust RGB, and severe convection RGB can be used for this but they shouldn’t be depended on in all situations to differentiate the cloud heights, especially at night with low-level clouds. The other imagery are not useful at night, or cannot see low enough in the atmosphere to see these clouds.
Identify the two different height clouds in the following drag and drop interaction.



Use the above radio buttons to switch between imagery options, then drag the two different heights onto the appropriate clouds.
The cloud heights can be differentiated by cloud type or by colour in the different imagery. In the IR imagery, the lower clouds are smoother in texture. In the night microphysics RGB, the lower clouds have a center that contains sparse yellow-green speckling. In the dust RGB, the lower clouds are yellow with green edging. All the rest of the clouds are higher in that vicinity.
For an objective analysis of the entire infrared image, use the below image where red areas are low-level, green areas are mid-level, and blue areas are high-level clouds. Some clouds were not captured as they were too small for the objective analysis to pick out.
This is not an operational product as it is for instructional purposes only.
Identify the areas that are land and ocean by dragging land and ocean markers to various locations that you can identify with the seven available images. Use the radio buttons below the imagery to switch the imagery type for ease of finding the surface features.







Use the above radio buttons to switch between imagery options, then drag the “land” and “ocean” labels to the correct locations on the image.
Option 6 makes it easier to define where land and ocean are. Ocean is dark blue or black, and land varies from earth tones through greens. In the areas where the natural colour imagery is dark, you can use other channels and products to help you identify the difference. The night microphysics RGB can be useful to help you differentiate clouds from land from ocean.
The following night microphysics RGB image shows an objectively-analyzed land and ocean mask. The land areas are coloured brown and the ocean areas are coloured blue. Areas where you can see the night microphysics RGB are areas where it iss too cloudy to differentiate the surface features.
Arrange the list of products to the order of the options in the comparison slider above. For instance, if you believe "option 1" in the comparison slider to be the night microphysics RGB, move the "night microphysics RGB" answer choice to be the first in the following list.
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