Image Archive
Frequently Asked Questions
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What is this?
This is a web accessible collection of images maintained by the Precipitation Diagnostics Group (PDG) in the Mesoscale and Microscale Meteorology Division of NCAR. The images encompass a wide range of platforms including satellite, radar, surface, upper-air, and model output. The spatial domain is largely limited to the central United States and, prior to 2002, the warm season. Although PDG did not create the images and is not responsible for their content, a large portion of the archive originates from within NCAR. The archive was originally created for PDG members, but was transferred to the World Wide Web for use by partner institutions.How do I get the raw data?
Except for WSI radar composites, we do not have raw data. The case selection kit was not intended to be a comprehensive raw data repository. Only images were saved.Where did you get the images?
Why did you create this?
To summarize daily weather over the U.S. and help isolate potential case study periods.What types of images do you have?
Image selection varies depending on availability and the time of year. It has evolved over time to accommodate changing image sources and additional image types. We may broaden the selection during field campaigns or otherwise interesting weather events. The image types were chosen for their potential to isolate and identify case-study periods during the warm season over the U.S.Why is this time missing?
Internet downtime, 3rd party web page changes, or other circumstances beyond our control may prevent us from downloading images for extended periods. Alternate images from secondary sites sometimes fill in the gaps.Alternate sites
Many external sites have supplemental image archives. For example:
- Atmospheric Radiation Measurement (ARM) Program
- Joint Office for Science Support (UCAR)
- NCDC Historical GOES Browse server
- NCDC National mosaic reflectivity images
- Plymouth State Weather Center
- SPC Mesoscale analysis archive
- SPC Severe weather report archive
Technical
Are the time stamps wrong?
A time stamp shown in an image is generally correct. The image filename, on the other hand, may contain a later time. The two times should never be more than an hour apart. The time embedded in the filename corresponds to the time the image was added to the archive. Near the end of the day (in UTC), this may cause an image to be bumped to the following day.
Cookies
Cookies keep track of your most recently chosen date, max_frames value, extra_days value, and image category. They also retain your animation settings. No personal information is kept.Printing an image
Printing web pages can be tricky, especially when dealing with HTML frames. The following suggestions may help. First pause the animation on the image you desire. In Microsoft Internet Explorer, right-click in the whitespace above or below the image, and press Print. This brings up the print dialog window, from which you can choose a printer, print to a file, or change the options. In other browsers, try saving the image by right-clicking it and selecting Save Image As.... After saving the image, use other software to print the image independently from the browser.Downloading a lot of images and Making a movie
Making a movie usually requires downloading a lot of images. This is facilitated by the Image list link at the bottom of each animation window. Clicking this link produces a list of URLs for all images in the animation. Write a script like this to download the images and use 3rd party software to create the movie.
I can't change the date!
Try pressing the Go! button after selecting a new date.The Back link/button does not work.
The Back link in the animation frame may not work properly in some browsers. If you run into this problem, try the browser's Back feature or click the Go! button in the left panel. These all should have the same effect.No images for X or The page cannot be found
No images were saved for this date.Sorry! Image category unavailable for X. Change date or increase "extra days".
The image type may be listed, but no images are available for the initial date. This accomodates the "extra days" feature. If you increase the number of extra days, the animation should begin, but without images from the first requested date. The author would change this confusing behavior, but has yet to devise a solution using static HTML.
Please report problems to Dave Ahijevych at ahijevyc@ucar.edu
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