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The Use of Satellite Imagery to Assess Tornado Damage in the Central Appalachian Region Case Study: April 28 th , 2002 La Plata, MD. Tornado Ongoing Research Remote Sensing Imagery Analysis/Discussion Overview Data Providers 0 20 40 60 80 100 120 140 160 0 200 400 600 800 1000 1200 1400 1600 1800 2000 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Tornado Count Tornado Count Country vs. Regional Tornadoes by Year US Tornadoes by Year Central Appalachian Tornadoes by Year 0 50 100 150 200 250 300 350 400 450 0 2000 4000 6000 8000 10000 12000 14000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Tornado Count Tornado Count Country vs. Regional Tornadoes by Month US Tornadoes by Month Central Appalachian Tornadoes by Month Figure 1: Tornado track layer (NOAA-SPC) overlaid onto a USGS Digital Elevation Layer. La Plata, Maryland (March 14, 2002) Landsat Band 3 La Plata, Maryland (May 5, 2002) Landsat Band 3 Intensity F-4* Length 64 Miles Injuries 122 Fatalities 3 Property Damage > $100 million EF-Scale implemented in 2007 (*) Picture and data compliments of DOC published Service assessment Accessibility Frequency Resolution Inventory Google Earth Public Variable/Limited Variable (High) Variable Landsat 7^ Public 16 Days 30 Meter 1999 – Present Landsat 8 Public 16 Days 30 Meter (MS) 2013 – Present MODIS Public 1 - 2x Daily 250 Meter (R/NIR) 2000 - Present Aster Public 16 Days/Variable 15 Meter 2000 - Present NDVI Public Dependent on Source Dependent on Source Dependent on Source NLCD Public 5 Years 30 Meter 1992, 2001, 2006, 2011 Aerial Photos Variable Variable Variable (High) Variable Table 3 Figure 5 Figure 6 Figure 8 Figure 7 Objectives Determine the advantages and disadvantages of different remote sensing techniques in the detection and refinement of tornado damage paths, with a focus eventually on weaker tornadoes in remote areas. Create a matrix to be used at the warning forecast office level, highlighting the availability of these images, along with their timeliness and ease of accessibility for use in post-tornadic event assessments. Damage visibility: imagery type vs. magnitude of event At what EF rating is each imagery type useful in determining presence of tornado damage? 5 cases per magnitude category. How often is damage observed using each imagery type? Damage visibility: land cover differences in damage visibility Does the land cover type significantly affect how visible damage is between the imagery types? Damaged land reclamation How long after an event does the damage persist? Does that change depending on event intensity? Automated tornado detection based on before and after remotely sensed images References An overview of the imagery considered is shown in Table 3 above. The study focused mainly on easily accessible technologies at a warning forecast office site. Takeaways: Cloud cover often negatively affects the frequency of available images across all platforms considered. In general, as the resolution of the products increased, the frequency, inventory, and image window decreased. Greater data storage is required for higher resolution imagery The availability and use of aerial photographs is highly variable, and situationally dependent. Google Earth images have very high resolution with little data storage. However, it is highly variable and at times, limited. Seasonal differences can provide a large source of error within each platform, especially in the spring and fall with foliage gains and losses. A comprehensive review of the 2002 La Plata, Maryland tornado was completed due to the event’s high intensity, known data availability, past available research conducted, and close proximity to the central Appalachian Mountains Region. Two types of satellite images are presented below, along with a National Weather Service damage path image (originally published in the September 2002 service assessment) (Figure 4). Using both Landsat 7 (Figures 5 + 6) and Google Earth (Figures 7 + 8) before and after images, a definable tornado scar from the event is clearly visible in the same areas outlined by the storm survey in the F2 to F4 damage range. Intermittent damage is also visible in the lower damage classified areas, especially in the lower resolution Landsat imagery. While the Google Earth images were at a higher resolution, the damage wasn’t as noticeable throughout the study area. This was mainly due to the elapsed time between the event and the image date. Landsat 7 images have a recurrence interval of 16 days, while Google Earth images are highly variable both spatially and temporally, especially pre-2008. In this circumstance, the Landsat 7 image (Figure 6) was taken only a week after the event, providing the user with rapid and more useful data. The next available Google Earth image (Figure 8) was taken approximately 3 years after the event, which introduces both natural and industrial land reclamation error to the image. Also, the comparison before image (Figure 7), is incomplete spatially, with portions of the image dating back to the 1980s, which leads to a significant loss in resolution. Thus, while higher resolution Images would be more beneficial for the users in this circumstance, other factors can certainly limit it’s overall utility. United States of America. Department of Commerce. NOAA - National Weather Service. Service Assessment- La Plata, Maryland, Tornado Outbreak of April 28, 2002. N.p.: n.p., n.d. Print. *Additional References are available upon request Table 1 Figure 2 Figure 3 Table 2 Figure 4 ^ May 31, 2003- Scan line corrector failure on Landsat 7 imager
Transcript
Page 1: The Use of Satellite Imagery to Assess Tornado Damage in ... · Assessment- La Plata, Maryland, Tornado Outbreak of April 28, 2002. N.p.: n.p., n.d. Print. *Additional References

The Use of Satellite Imagery to Assess Tornado Damage in the Central Appalachian Region

Case Study: April 28th, 2002 La Plata, MD. Tornado

Ongoing Research

Remote Sensing Imagery Analysis/Discussion

Overview

Data Providers

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Country vs. Regional Tornadoes by Month

US Tornadoes by Month Central Appalachian Tornadoes by Month

Figure 1: Tornado track layer (NOAA-SPC) overlaid onto a USGS Digital Elevation Layer.

La Plata, Maryland (March 14, 2002) Landsat Band 3

La Plata, Maryland (May 5, 2002) Landsat Band 3

Intensity F-4*

Length 64 Miles

Injuries 122

Fatalities 3

Property Damage > $100 million

• EF-Scale implemented in 2007 (*) • Picture and data compliments of DOC published

Service assessment

Accessibility Frequency Resolution Inventory

Google Earth Public Variable/Limited Variable (High) Variable

Landsat 7^ Public 16 Days 30 Meter 1999 – Present

Landsat 8 Public 16 Days 30 Meter (MS) 2013 – Present

MODIS Public 1 - 2x Daily 250 Meter (R/NIR) 2000 - Present

Aster Public 16 Days/Variable 15 Meter 2000 - Present

NDVI Public Dependent on Source Dependent on Source Dependent on Source

NLCD Public 5 Years 30 Meter 1992, 2001, 2006, 2011

Aerial Photos Variable Variable Variable (High) Variable

Table 3

Figure 5 Figure 6

Figure 8 Figure 7

Objectives

• Determine the advantages and disadvantages of different remote sensing techniques in the detection and refinement of tornado damage paths, with a focus eventually on weaker tornadoes in remote areas.

• Create a matrix to be used at the warning forecast office level, highlighting the

availability of these images, along with their timeliness and ease of accessibility for use in post-tornadic event assessments.

• Damage visibility: imagery type vs. magnitude of event • At what EF rating is each imagery type useful in determining

presence of tornado damage? • 5 cases per magnitude category. How often is damage observed

using each imagery type? • Damage visibility: land cover differences in damage visibility

• Does the land cover type significantly affect how visible damage is between the imagery types?

• Damaged land reclamation • How long after an event does the damage persist? • Does that change depending on event intensity?

• Automated tornado detection based on before and after remotely sensed images

References

An overview of the imagery considered is shown in Table 3 above. The study focused mainly on easily accessible technologies at a warning forecast office site.

Takeaways: • Cloud cover often negatively affects the frequency of available images across all

platforms considered. • In general, as the resolution of the products increased, the frequency, inventory,

and image window decreased. • Greater data storage is required for higher resolution imagery • The availability and use of aerial photographs is highly variable, and situationally

dependent. • Google Earth images have very high resolution with little data storage. However, it

is highly variable and at times, limited. • Seasonal differences can provide a large source of error within each platform,

especially in the spring and fall with foliage gains and losses.

A comprehensive review of the 2002 La Plata, Maryland tornado was completed due to the event’s high intensity, known data availability, past available research conducted, and close proximity to the central Appalachian Mountains Region. Two types of satellite images are presented below, along with a National Weather Service damage path image (originally published in the September 2002 service assessment) (Figure 4). Using both Landsat 7 (Figures 5 + 6) and Google Earth (Figures 7 + 8) before and after images, a definable tornado scar from the event is clearly visible in the same areas outlined by the storm survey in the F2 to F4 damage range. Intermittent damage is also visible in the lower damage classified areas, especially in the lower resolution Landsat imagery. While the Google Earth images were at a higher resolution, the damage wasn’t as noticeable throughout the study area. This was mainly due to the elapsed time between the event and the image date. Landsat 7 images have a recurrence interval of 16 days, while Google Earth images are highly variable both spatially and temporally, especially pre-2008. In this circumstance, the Landsat 7 image (Figure 6) was taken only a week after the event, providing the user with rapid and more useful data. The next available Google Earth image (Figure 8) was taken approximately 3 years after the event, which introduces both natural and industrial land reclamation error to the image. Also, the comparison before image (Figure 7), is incomplete spatially, with portions of the image dating back to the 1980s, which leads to a significant loss in resolution. Thus, while higher resolution Images would be more beneficial for the users in this circumstance, other factors can certainly limit it’s overall utility.

United States of America. Department of Commerce. NOAA - National Weather Service. Service Assessment- La Plata, Maryland, Tornado Outbreak of April 28, 2002. N.p.: n.p., n.d. Print.

*Additional References are available upon request

Table 1

Figure 2

Figure 3

Table 2

Figure 4

^ May 31, 2003- Scan line corrector failure on Landsat 7 imager

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