{ "culture": "en-US", "name": "aria_dist", "guid": "0A30AE3C-771C-42E2-9288-9801C0D0E730", "catalogPath": "", "snippet": "OPERA Surface Disturbance Map from Harmonized Landsat Sentinel-2 for Hurricane Helene", "description": "

Date of Images:<\/SPAN><\/P>

10/2/2024 at 16:11 UTC (12:11 PM EDT)<\/SPAN><\/P>

Summary:<\/SPAN><\/P>

The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory and California Institute of Technology derived the disturbance maps using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. <\/SPAN><\/P>

The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who want to have a rough first look at the surface disturbance extent. The ARIA-share website has always focused on posting preliminary results as fast as possible for disaster response.<\/SPAN><\/P>

OPERA DIST-ALERT-HLS<\/SPAN><\/P>

The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the vegetation disturbance status (VEG-DIST-STATUS) and the maximum vegetation anomaly value (VEG-ANOM-MAX) layers. Images are provided from October 2, 2024. Each image consists of multiple MGRS tiles that were merged together for a composite image saved as a GeoTIFF file.<\/SPAN><\/P>

VEG-<\/SPAN>DIST<\/SPAN>-STATUS<\/SPAN><\/P>

Indication of vegetation cover loss (vegetation disturbance). The status label is based on the maximum anomaly value, confidence level, and whether it is ongoing or finished. \"First\" means the pixel has had an anomaly detection but no subsequent observations whether anomalous or not. \"Provisional\" means there have been two consecutive disturbance detections but not yet high confidence. \"Confirmed\" means that vegetation disturbance is detected with high confidence. The label \"finished\" is applied to confirmed disturbances that have had two consecutive no-anomaly observations or one 15 days or more after the last anomaly detection. If a new disturbance is detected, it will overwrite those in a \"finished\" state. These labels are reported for both above and below the 50% disturbance threshold based on the maximum anomaly value.<\/SPAN><\/P>

VEG-ANOM-MAX<\/SPAN><\/P>

Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year.<\/SPAN><\/P>

The DSWx-S1 products have these flags:<\/SPAN><\/P>

250 (light gray) and 251 (dark gray) represent HAND and layover/shadow masks, respectively.<\/SPAN><\/P>

Suggested Use:<\/SPAN><\/P>

VEG-ANOM-MAX<\/SPAN><\/P>