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Dates of Images:
Dates: 04/20/2024 (pre-flood), 05/06/2024, 05/07/2024, 05/09/2024, 05/15/2024, 05/21/2024 Time Zone: GMT (local crossing time of ~1:00 pm)
Summary:
These are NDWI measurements from PACE OCI using surface reflectances from OCI's SFREFL suite of the 2024 flooding in Brazil. NDWI is a normalized band ratio using the green (555 nm) and NIR (860 nm) for water content detection (green - nir / green + nir). The images show how the flood developed from a pre-flood day (04/20/2024) to the proceeding flooded days (through 05/21/2024) at ~1:00 local time (the overpass of the instrument). The changing extent of the floodwaters, along with what looks to be the amount of suspended sediment, is especially clear against the background of vegetation. Users should take into account that these floodwaters were sediment-laden, and thus some of that signal may depress the water signal. However, the change in NDWI from the pre-flood day can be used to identify flood extent.
Suggested Use:
NDWI is a normalized band ratio measuring the presence of water. Higher positive values water surfaces, low positive values to ~0 indicates flooding or high humidity, and negative values mean non-aqueous or drought conditions. In these images, it is clear that the presence of water increases greatly around the Jacui River during flood days compared to the pre-flood day (04/20/2024), showing the transition of the area around the Jacui River from non-flooded conditions (low NDWI values) to flooded (higher NDWI). Clouds have been screened from these products.
Satellite/Sensor/Resolution:
Satellite: PACE, sensor: OCI
Temporal resolution: daily
Spatial resolution: gridded to 0.015 degrees from a Level 2 product in instrument swath (varying pixel size, 1.2 km at nadir).
Credits:
NASA PACE Team, POC: Skye Caplan, Link to data: https://search.earthdata.nasa.gov/search/granules?p=C3620139902-OB_CLOUD&pg[0][v]=f&pg[0][gsk]=-start_date&q=oci%20sfrefl
Dates of Images:
Dates: 04/20/2024 (pre-flood), 05/06/2024, 05/07/2024, 05/09/2024, 05/15/2024, 05/21/2024 Time Zone: GMT (local crossing time of ~1:00 pm)
Summary:
These are NDWI measurements from PACE OCI using surface reflectances from OCI's SFREFL suite of the 2024 flooding in Brazil. NDWI is a normalized band ratio using the green (555 nm) and NIR (860 nm) for water content detection (green - nir / green + nir). The images show how the flood developed from a pre-flood day (04/20/2024) to the proceeding flooded days (through 05/21/2024) at ~1:00 local time (the overpass of the instrument). The changing extent of the floodwaters, along with what looks to be the amount of suspended sediment, is especially clear against the background of vegetation. Users should take into account that these floodwaters were sediment-laden, and thus some of that signal may depress the water signal. However, the change in NDWI from the pre-flood day can be used to identify flood extent.
Suggested Use:
NDWI is a normalized band ratio measuring the presence of water. Higher positive values water surfaces, low positive values to ~0 indicates flooding or high humidity, and negative values mean non-aqueous or drought conditions. In these images, it is clear that the presence of water increases greatly around the Jacui River during flood days compared to the pre-flood day (04/20/2024), showing the transition of the area around the Jacui River from non-flooded conditions (low NDWI values) to flooded (higher NDWI). Clouds have been screened from these products.
Satellite/Sensor/Resolution:
Satellite: PACE, sensor: OCI
Temporal resolution: daily
Spatial resolution: gridded to 0.015 degrees from a Level 2 product in instrument swath (varying pixel size, 1.2 km at nadir).
Credits:
NASA PACE Team, POC: Skye Caplan, Link to data: https://search.earthdata.nasa.gov/search/granules?p=C3620139902-OB_CLOUD&pg[0][v]=f&pg[0][gsk]=-start_date&q=oci%20sfrefl