{ "culture": "en-US", "name": "modis_flood_1_day", "guid": "", "catalogPath": "", "snippet": "MODIS NRT Flood Product (MCDWD): 1-day composite, cloud-shadow masking applied.", "description": "
The MODIS NRT Global Flood product (MCDWD) reports flood and surface water detected by NASA's MODIS optical instrument. This instrument is carried on two NASA satellites, Terra and Aqua, and thus provides twice-daily near-global observations. It is an optical instrument so cannot see through clouds.<\/span><\/p> The product is delivered as 1, 2, and 3-day composites. These alternatives are provided to minimize the influence of clouds on the product: clouds will block the satellite view of the surface (potentially causing false-negatives where the product does not detect water), and cloud shadows can be erroneously detected as water (potentially causing false-positives where the product predicts water or flood occurrence when there is none).<\/span><\/p> The 1-day product only uses observations from the product date, and will report water if it is detected by any single observation (in general over one day, there will be two observations, one from each satellite).<\/span><\/p> The 2- and 3-day products combine observations over the current plus previous day (2-day), or current plus two previous days (3-day), and require multiple water detections before a pixel is marked as water in the output. This can dramatically reduce false-positives from cloud-shadows, and may permit flooding to be observed when clouds move out of the way. But they may also not be as up-to-date as the 1-day product.<\/span><\/p> Link to 2-day product: <\/span>https://maps.disasters.nasa.gov/arcgis/home/item.html?id=f7178cdbcc434ff09538999ab5ce8d83<\/a><\/p> Link to 3-day product: https://maps.disasters.nasa.gov/arcgis/home/item.html?id=b33741d95e924507b75b334f16ec23f1<\/a>
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