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Digital Earth Africa’s Monthly NDVI Anomaly service provides estimate of vegetation condition, for each caldendar month, against the long-term baseline condition measured for the month from 1984 to 2020 in the NDVI Climatology. A standardised anomaly is calculated by subtracting the long-term mean from an observation of interest and then dividing the result by the long-term standard deviation. Positive NDVI anomaly values indicate vegetation is greener than average conditions, and are usually due to increased rainfall in a region. Negative values indicate additional plant stress relative to the long-term average. The NDVI anomaly service is therefore effective for understanding the extent, intensity and impact of a drought.Abrupt and significant negative anomalies may also be caused by fire disturbance.
From September 2022, the Monthly NDVI Anomaly is generated as a low latency product, i.e. anomaly for a month is generated on the 5th day of the following month. This ensures data is available shortly after the end of a month and all Landat 9 and Sentinel-2 observations are included. Not all landsat 8 observations for the month will be used, because the Landsat 8 Surface Refelectance product from USGS has a latency of over 2 weeks ([see Landsat Collection 2 Generation Timeline (https://www.usgs.gov/media/images/landsat-collection-2-generation-timeline)).
DE Africa makes this data available under the Creative Commons Attribute 4.0 license https://creativecommons.org/licenses/by/4.0/.
https://docs.digitalearthafrica.org/en/latest/data_specs/NDVI_Anomaly_specs.html
See all datasets managed by Digital Earth Africa.
helpdesk@digitalearthafrica.org
Digital Earth Africa Monthly Normalised Difference Vegetation Index (NDVI) Anomaly was accessed on DATE from https://registry.opendata.aws/deafrica-ndvi_anomaly.
arn:aws:s3:::deafrica-services/ndvi_anomalyaf-south-1aws s3 ls --region af-south-1 --no-sign-request s3://deafrica-services/ndvi_anomaly/arn:aws:s3:::deafrica-services-inventoryaf-south-1aws s3 ls --region af-south-1 --no-sign-request s3://deafrica-services-inventory/