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remote_sensing_methods:burned_area_reflectance_classification_barc [2013/09/13 12:06] (current)
jgh created
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 +<​sup>​[[:​bug_reporting|Report a bug, broken link, or incorrect content]]</​sup>​[[http://​methods.landscapetoolbox.org|{{ field_methods:​methodsguide3.png?​220x120|}}]]
 +====== Burned Area Reflectance Classification ======
 +[[http://​www.landscapetoolbox.org/​about/​get_involved|{{:​abstract_in_dev.gif|}}]]\\
 +Written by: Grant Hamilton
 +
 +===== Other Names =====
 +BARC
 +
 +===== Description =====
 +Burned Area Reflectance Classification (BARC) is a method using remotely sensed data to assess the severity of fire damage to vegetated areas developed by the US Forest Service and US Geological Survey. ​ It is premised on the contrast in near infrared (NIR) and mid infrared (MIR) reflectance between pre-fire vegetated surfaces and post-fire denuded surfaces: "​Imagery collected over a forest in a pre-fire condition will have very high near infrared band values and very low mid infrared band values. Imagery collected over a forest after a fire will have very low near infrared band values and very high mid infrared band values"​ (USFS Remote Sensing Applications Center, n.d.).  ​
 +
 +{{:​remote_sensing_methods:​barc_spectral_response.png}}
 +
 +
 +<​sub>​Source:​ USFS</​sub>​
 +
 +===== Related Methods =====
 +• [[remote_sensing_methods:​normalized_difference_vegetation_index|]] (NDVI)
 +
 +• [[remote_sensing_methods:​enhanced_vegetation_index|]] (EVI)
 +
 +• [[remote_sensing_methods:​normalized_burn_ratio|]] (NBR)
 +
 +===== Calculating Burn Severity Using BARC =====
 +Burn severity is calculated using [[remote_sensor_types:​landsat_etm_7]] and/or [[remote_sensor_types:​landsat_8]] imagery. ​ The [[normalized_burn_ratio]] (NBR) is used to assess a fire's severity:
 +
 +//%%((Band 4 - Band 7) / (Band 4 + Band 7)) x 1000 = NBR%%//
 +
 +where Band 4 includes wavelengths from 0.76-0.90 µm (NIR) and Band 7 includes wavelengths between 2.09-2.35 µm (SWIR). ​ If pre-fire imagery is available the differenced Normalized Burn Ratio (dNBR) is used:
 +
 +//​%%Pre-fireNBR - Post-fireNBR = dNBR%%//
 +
 +Higher dNBR indicate more severe damage. ​ Areas with negative dNBR values may indicate increased vegetation productivity following a fire.  "​Non-Processing Areas" include parts of the image obscured by clouds or smoke or water bodies.  ​
 +
 +===== Accessing Datasets ​ =====
 +=== Recent and Near Real-time Data - Burned Area Emergency Response (BAER) ===
 +Datasets for recent (generally in the current year) and ongoing fires cannot be downloaded on demand. ​ The user must submit a request which is processed by the Burned Area Emergency Response (BAER) team.  Delivery of datasets may take some time depending on the length of the request queue. ​ BAER data is intended for federal and state incident managers. ​ BAER's imagery request queue is available at http://​svinetfc6.fs.fed.us/​birch/​.
 +
 +=== Historic Data (1984 - 2011) - Monitoring Trends in Burn Severity (MTBS) ===
 +Only fires of greater than 1,000 acres in the western conterminous United States (CONUS) and greater than 500 acres in the eastern CONUS are recorded. ​ Data also covers Alaska, Hawaii, and Puerto Rico.  Fires on both private and public property are recorded. ​ Historic data can be downloaded on demand from the Monitoring Trends in Burn Severity (MTBS) website at http://​mtbs.gov/​compositfire/​mosaic/​bin-release/​download.html. ​  
 +
 +===== Explanation of BARC Datasets =====
 +As they are derived from [[remote_sensor_types:​landsat_etm_7|Landsat 7]] and/or [[remote_sensor_types:​landsat_8|Landsat 8]] imagery, BARC datasets have a resolution of 30m.  ​
 +
 +BAER 8-bit datasets contain unclassified values of for use by BAER teams in the field. ​ These datasets are referred to as BARC-256 by federal agencies.  ​
 +
 +MTBS datasets are available as mosaics of the CONUS, Alaska, Hawaii, or Puerto Rico.  They are in ERDAS Imagine (.img) format. ​ MTBS dataset values are classified into four levels of fire damage severity using a variety of methods, e.g. Jenks Natural Breaks; wherever possible the Landsat TM derived datasets are calibrated with field data (Hudak, et al, 2004). ​ These datasets are referred to as BARC-4 by federal agencies. ​ MTBS suggests the following symbology: ​
 +
 +//Value 1 = Very Low or Unburned (Dark Green)//​\\ ​
 +//Value 2 = Low (Cyan)//​\\ ​
 +//Value 3 = Moderate (Yellow)//​\\ ​
 +//Value 4 = High (Red)//​\\ ​
 +
 +Values of 0 indicate "​Background/​No Data", values of 5 indicate "​Increased Greenness/​Increased Vegetation Response",​ and values of 6 indicate "​Non-Processing Area Mask".
 +
 +{{:​remote_sensing_methods:​barc_ex.png}}
 +
 +**Damage severity of the 2011 Abrams Fire on the eastern slope of the Organ Mountains in New Mexico. ​ This map was created in ArcMap 10 using the MTBS mosaic and suggested symbology.** ​  
 +
 +===== Technical References =====
 +Hudak, A.T., Robichaud, P.R., Evans, J.B., Clark, J., Lannom, K., Morgan, P., Stone, C.  2004. Field validation of Burned Area Reflectance Classification (BARC) products for post fire assessment. ​  In Greer, J.D, ed. //Remote sensing for field users; proceedings of the tenth Forest Service remote sensing applications conference//,​ April 5–9; Salt Lake City, UT. http://​www.treesearch.fs.fed.us/​pubs/​23530.  ​
 +  * Discusses calibrating Landsat TM derived dNBR values to field-collected data.
 +
 +USFS Remote Sensing Applications Center. n.d. BARC - Frequently asked questions. http://​www.fs.fed.us/​eng/​rsac/​baer/​barc.html.  ​
 +  * Includes a tutorial on calibrating BAER-256 datasets to field-collected data.
 +
 +===== Datasets =====
 +  * USFS. BAER imagery support, BARC request page - http://​svinetfc6.fs.fed.us/​birch/​requests
 +
 +  * USGS and USFS. National MTBS Burn Severity Mosaics - http://​mtbs.gov/​compositfire/​mosaic/​bin-release/​download.html
 +
 +===== Discussion/​Comments =====
 +<​sub>​**You must have an account and be logged in to post or reply to the discussion topics below. [[http://​wiki.landscapetoolbox.org/​doku.php/​Home?​do=login&​sectok=db3676cff5bcd873b609b4e582432d73|Click here]] to login or register for the site.**</​sub>​
 +~~DISCUSSION| ~~
  
remote_sensing_methods/burned_area_reflectance_classification_barc.txt · Last modified: 2013/09/13 12:06 by jgh