Data Analysis

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Data Analysis
The Data Analysis section is intended to encourage students to practice describing and interpreting patterns in spatial data.

This activity contains 7 questions.

In this section you will be analyzing and interpreting imagery and data related to a small storm which occurred in November 2004 off the west coast of British Columbia, Canada. Unless otherwise stated, the source for this imagery and data is California Regional Weather Server, located in the Geosciences Department at San Francisco State University.

The visible satellite image below will help you locate the storm in question (see the yellow arrow). Scrutinize it and answer the following questions.

Using Pacific Standard Time (Z minus 8hrs), what is the date and time of this image? What is the approximate latitude and longitude at the core of the storm? The image appears to darken to the northwest of the Aleutian Islands (in the upper left). Why is this?

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

Now, take a look at this image, taken at the same time, by the same satellite, but using a different sensor. (Please Note: The fact that this image is somewhat smaller is NOT significant to any of your answers below.)

This is an infrared image. What is the difference in appearance between the two? What is the fundamental difference between visible and infrared satellite images? Click here for a clear and concise primer on weather satellites and imagery.

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

The infrared image above is color-enhanced, though some infrared imagery is shown in gray-scale. For comparison, look at these two infrared images of the storm from NOAA taken a few hours later. The first is color-enhanced, while the second is in gray-scale.

With an infrared image, you are not actually seeing the clouds or the storm. The coloration, though, is an indicator of the temperatures of the cloud tops, which indirectly indicates the intensity of the storm . Using the key at the bottom of the color-enhanced image (the key is in degrees Celsius), what are the aproximate temperatures of the cloud tops? Are the cloud tops colder or warmer than the surroundings? Do you think this is an indicator of the warmer clouds closer to the surface or the taller, more vertically developed clouds which rise into the atmosphere? How can this indicate the intensity of the storm?

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

To get an even more detailed view of this storm, you will use an interactive weather image server to create a small animation. Go to here and set the browser for the following parameters:

Year - 2004
Month - November
Day - 16th
Animation length - 2 days
Interval between images - 1 hour

Once you have input these settings, click on "Build Animation." Watch the times and dates of the images change to get an idea of the timing of the storm. Initially, the storm is not evident or visible. What time and date (Pacific Standard Time) does the storm seem to form? What direction is it circulating (clockwise or counter-clockwise)? What direction is the storm itself migrating? What is the common name for the global wind system found at this latitude?

Using the same input data, create an infrared animation of the same storm. What do you notice that is new or different?

The infrared animation below may also help you answer some of these questions.

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

Use this surface weather map to answer the questions below.

Is this a high or low pressure system?
What is the pressure at the core, in millibars? (Hint: This is labeled in blue type if you look closely.)
What is the general term for such a storm, especially when it is found outside the tropics.
Is there any other associated phenomena that you are expecting to see?

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

The gray areas in this image below indicate the presence of a strong polar front jet stream. Do you think this was a factor in the formation of the storm? What does your text say? What is the term for the dips or undulations that are found in this jet stream?

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

Finally, look at this weather map from the National Weather Service.

As you might have predicted, this storm has given rise to two classic weather phenomena. What are the common terms for these phenomena, and what is likely happening in each? In other words, how do they differ?

To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

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