Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2024-07-12 Title: Soil Burn Severity Dataset for the South Fork Fire occurring on the Mescalero Agency and Lincoln National Forest Publication Information Publication Place: Salt Lake City, Utah, USA Publisher: USDA Forest Service Geospatial Data Presentation Form: raster digital data Online Linkage: https://fsapps.nwcg.gov/afm/baer/download.php Description Abstract: This soil burn severity dataset was derived from Sentinel 2 data and field validated by a Forest Service Burned Area Emergency Response (BAER) team. It is based upon an initial Burned Area Reflectance Classification (BARC) dataset created by analyzing satellite imagery. A pre-fire and post-fire Sentinel 2 scene were processed to develop a differenced Normalized Burn Ratio (dNBR) image. The dNBR image attempts to portray the variation of burn severity within a fire and captures the combined effects of the fire to vegetation and soil components of the ecosytem. The preliminary BARC dataset was assessed by a Forest Service BAER team and modified, if necessary, based on field conditions. Purpose: These data were created by the USDA Forest Service Geospatial Technology and Applications Center (GTAC) to support Burned Area Emergency Response (BAER) teams. Supplemental Information Fire Name: South Fork Agency: USDA Forest Service Type of assessment: Emergency Fire size (as mapped): 17060 acres Pre-Fire Imagery Date : 2022-04-28 Post-Fire Imagery Date : 2024-06-26 Output Dataset Projection: NAD_1983_UTM_Zone_13N Datum: D_North_American_1983 Spheroid Name: GRS_1980 Mapping Comments: None Product List south_fork_nm3333810576620240617_sbs.tif = Soil burn severity (SBS) dataset in raster format south_fork_nm3333810576620240617_SBS.png = PNG thumbnail version of the SBS Time Period of Content Multiple Dates/Times Single Date/Time Calendar Date: 2022-04-28 (pre-fire image) Single Date/Time Calendar Date: 2024-06-26 (post-fire image) Currentness Reference: Severity data correspond to the date of the post-fire image. Status Progress: Evaluation of methods in process Maintenance and Update Frequency: As needed Spatial Domain Bounding Coordinates West Bounding Coordinate: 426377.2246242813 East Bounding Coordinate: 440807.2246242813 North Bounding Coordinate: 3697323.3360778526 South Bounding Coordinate: 3687633.3360778526 Keywords Theme Theme Keyword Thesaurus: none Theme Keyword: Wildland Fire Theme Keyword: Wildfire Theme Keyword: Burned Area Emergency Response Theme Keyword: BAER Theme Keyword: dNBR Theme Keyword: Fire Severity Theme Keyword: Burn Severity Theme Keyword: USDA Forest Service Place Place Keyword Thesaurus: none Place Keyword: NM Place Keyword: south fork Fire Access Constraints: These data are publicly available. Use Constraints: There are no restrictions on use, except for reasonable and proper acknowledgement of information sources and limitations as preliminary/draft data. Data Set Credit: USDA Forest Service Native Data Set Environment: GeoTiff Data Quality Information Positional Accuracy Horizontal Positional Accuracy Horizontal Positional Accuracy Report: Landsat data are terrain corrected using ground control points and processed to an RMSE of less than 1/2 pixel. Lineage Process Step Process Description: These data products are derived from Sentinel 2 data. Pre-fire and post-fire scenes are analyzed to create a differenced Normalized Burn Ratio (dNBR) image. The dNBR image portrays the variation of burn severity within the fire. The pre- and post-fire images are terrain corrected and further processed to convert top of atmosphere reflectance. The Normalized Burn Ratio (NBR) is computed for the pre- and post-fire images using the following formula: (NIR Band - SWIR Band) / (NIR Band + SWIR Band) = NBR The Differenced NBR is computed to determine severity by subtracting the post-fire NBR from the pre-fire NBR: (PreNBR - PostNBR) = dNBR Due to a lack of timely satellite imagery without cloud cover, the initial BARC was processed with large areas obscured by clouds. An earlier run of imagery provided some information of those areas, but it was of poorer quality due to the temporal and spectral nature of the collection. The previous run only provided nNDVI, and a 4 class BARC product. In order to build the most accurate SBS layer, we combined these two layers and used significant input and field validation to blend these clouded areas into a more accurate and comprehensive SBS. First the clouded areas were isolated and vectorized from the dNBR 256 BARC. These were then used to clip that BARC, as well as isolate the older initial data to only those areas. Those two areas were then joined together, with the initial data resampled up to match the BARC. Once completed we took and readjusted the ranges of the BARC data to match the field observations of those areas. We then had the analysts help explain in great detail their field observations, then blended with the use of a pixel editor the areas of preliminary data under the cloud cover to try and interpret the reality on the ground as best we could with the information available. Once complete we blended these values. The values in those areas were assigned to pre-adjustment medians within each burn class to avoid the adjustment of those 256 values when that shift was implemented. Therefor those clouded areas do not exhibit a range of values within those 256 values, and are all one singular value within that range. Additional Comments: Due to this hybridized approach, the clouded areas have much less accuracy than the nonclouded areas, degrading the overall quality of the product. This caveat should be clear when using this Data. The clouded areas are available within the BAER data and therefore can be used to isolate the two approaches if there is a need to know where those interpolations were made. Original BARC thresholds: Unburned/Low threshold = 50 Low/Moderate threshold = 85 Moderate/High threshold = 140 Revised SBS thresholds: Unburned/Low threshold = 50 Low/Moderate threshold = 93 Moderate/High threshold = 166 General descriptions of the severity classes are below: Unburned / Very low: The area after the fire was indistinguishable from pre-fire conditions. This does not always indicate the area did not burn (i.e. canopy may be occluding the burn signal). Low: Areas of surface fire with little detected change in cover and little detected mortality of the dominant vegetation. Little to no change in the soil color, structure and condition occured. Moderate: This severity class is between low and high and means there is a mixture of detected effects on the dominant vegetation. High: Areas where the canopy has high to complete consumption. Changes to soil structure, color and condition are significant and hydrophobicity may have occured. Spatial Data Organization Information Direct Spatial Reference Method: Raster Raster Object Information Vertical Count: 1 Spatial Reference Information Horizontal Coordinate System Definition Planar Map Projection Map Projection Name: NAD_1983_UTM_Zone_13N Map Projection Parameters Standard Parallel: 0.0 Standard Parallel: 0.0 Longitude of Central Meridian: -105.0 Latitude of Projection Origin: 1.0]];-5120900 -9998100 450445547.391054;-100000 10000;-100000 10000;0.001;0.001;0.001;IsHighPrecisio False Easting: 500000.0 False Northing: 0.0 Planar Coordinate Information Planar Coordinate Encoding Method: row and column Coordinate Representation Abscissa Resolution: 30.0 Ordinate Resolution: 30.0 Planar Distance Units: Meter Geodetic Model Horizontal Datum Name: D_North_American_1983 Ellipsoid Name: GRS_1980 Semi-major Axis: 6378137.0 Denominator of Flattening Ratio: 298.257222101 Distribution Information Resource Description: Downloadable Data Metadata Reference Information Metadata Date: 2024-07-12 Metadata Contact Contact Information Contact Organization Primary Contact Organization: USDA Forest Service, Geospatial Technology and Applications Center (GTAC) Contact Person: Mark Nigrelli Contact Address Address Type: mailing address Address: 125 S. Sate St., Suite 7105 City: Salt Lake City State or Province: UT Postal Code: 84138 Contact Voice Telephone: 801 975 3479 Contact Electronic Mail Address: baerimagery@fs.fed.us