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Published byHailey Purks Modified over 9 years ago
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Robert DeMaria
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Motivation Objective Data Center-Fixing Method Evaluation Method Results Conclusion
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Only west Atlantic has routine hurricane hunter aircraft for finding storm centers Satellite data used subjectively to find centers across the globe Improvements to accuracy in real- time highly desirable sos.noaa.gov/Education/tracking.html
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Geostationary satellites produce Infrared(IR) every 15 Minutes Forecast produced every 6 hours Due to time constraints, most of these images are unused Automatic method for estimating tropical cyclone location is highly desirable
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Tropical cyclones are roughly circular Use Circular Hough Transform (CHT) to produce estimate for tropical cyclone location by finding circles in IR imagery Compare accuracy to National Hurricane Center real-time center-fix
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2D Image of Temperature ◦ Created every 15 minutes
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A-Deck: Real-time estimate of position, velocity, wind speed, etc. ◦ Updated every 6 hours Best-Track: Improved a-deck data available after end of season
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Find a-deck position ◦ Given the time an IR image was created, look up most recent a-deck information and extrapolate position to IR image time Subset of IR image used ◦ Center image on a-deck position ◦ Image reduced to area around storm/area around eye ◦ Background removed from cloud shield using temperature threshold
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IR after subsect & thresholding:
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Laplacian of image performed to find edge pixels
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Circular Hough Transform performed for a range of radii on image Gaussian fit performed on accumulation space to produce center location
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For each time in best-track, find most recent IR image Estimate if eye is present in image ◦ If it is then perform center-fix searching for radii roughly the size of an eye ◦ If not, perform center-fix searching for radii roughly the size of the entire storm Error calculated as CHT center-fix distance from best-track location Compare error to that of the a-deck position
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Katrina 08/29/00 2005 Earl 09/02/06 2010 Charley 08/13/18 2004 Katrina 08/25/18 2005 Ericka 09/02/18 2009 Sandy 10/19/18 2012 No Eye Cases Eye Cases
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Charley 2004 – Very small but intense hurricane Katrina 2005 – Classic large, intense hurricane Ericka 2009 – Very disorganized weak tropical cyclone, did not make it to hurricane strength Earl 2010 – Strong hurricane in higher latitudes Sandy 2012 – Unusually large but only moderate strength, non-classical hurricane structure
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Mean a-deck error: 42 km Mean CHT error: 91 km Bias X: 6 km Bias Y: 8.5 km Bias Explained by Parallax
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Strong Circular Eye Greatly Improves Accuracy ◦ Eye Mean Error: 54 km ◦ No Eye Mean Error: 127 km ◦ Strong circular eyes are fairly rare
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Did not improve real-time center fix Rotational center may not be in center of cloud features: CHT may not be well suited to large-scale images CHT may be useful when an eye is present
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Use time-series information to improve Combine with information about vertical shear Improve eye estimation technique
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