Eye of the Storm - IDL Integral in Analyzing Satellite Imagery Used for Storm Tracking
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Customer Challenge
Ray Sterner of the Applied Physics Laboratory needed a data visualization solution that would allow anyone to view and track hurricanes on a website.
Solution Achieved
The summer of 2005 was an unusually active hurricane season, emphasized by record-breaking Katrina in August. Katrina is now considered one of the most costly natural disasters in American history. Although the high profile storm was devastating, it also initiated public interest in storms and weather patterns and prompted demand for better prediction capabilities.
In Katrina’s wake, the media hurried to obtain images of the storm to help the public appreciate the extent of the damage when the reality was hard to visualize. Many journal editors searching for images found the Johns Hopkins Applied Physics Laboratory (APL) Ocean Remote Sensing internet site, which is home to thousands of hurricane images in various states of their lifecycles that have been acquired since the early 1990’s.
The site, created in 1994 by APL researchers Ray Sterner and Steve Babin, began as a hobby after the pair conceptualized creating a repository for hurricane images that would be accessible by anyone with a computer. In 2005, they added stunning images of Katrina, most of which were processed using IDL® – a leading data visualization and analysis platform widely used in the scientific community.
The Katrina images were eventually featured in some of the most prestigious journals in the world, including National Geographic Magazine, which used images attained from the site for an August 2006 cover story.
Satellites Provide Consistent Information
To study hurricane patterns and behavior, scientists rely largely on satellite imagery, which provides them with the most frequent and accurate data available as a storm front forms, takes its course and dissipates.
The APL’s Ocean Remote Sensing site uses imagery acquired from instruments aboard the National Oceanographic and Atmospheric Administration’s (NOAA) polar-orbiting weather satellites to track the hurricanes featured on their website. The NOAA satellites orbit the Earth continuously, and can return up to two images per day of any particular point of interest, making the images a good source of change detection and pattern recognition.
Once data are acquired from NOAA’s Advanced Very High Resolution Radiometer (AVHHR), Sterner and Babin, a meteorologist, use advanced technology like IDL to produce visualizations of the weather patterns, including enhanced plots, charts, composites, overlays, and more.
Through the life of the site, Sterner has developed innovative processes using IDL to automate and enhance his image analyses. For instance, routines from his public IDL library plot storm movement and wind speed, make more visually intuitive overlay maps, and produce color images. He also used IDL to develop a stand alone application with windows following each hurricane, making important data accessible to anyone using the website.
Visit the APL website at http://fermi.jhuapl.edu/avhrr/index.html.
Key Benefits
- IDL allows the researchers to provide processed, up-to-date imagery of hurricanes
- Anyone interested in storm tracking can access easy-to-interpret images and track storm progress
- Using IDL allows the site creators to quickly and easily create new applications and routines to make processing the large amount of images