Monthly Global NDVI at 5 km based on AVHRR product - 1982 to 2019

Long-term monthly NDVI calculated through daily images of AVHRR (NOAA/CDR/AVHRR/NDVI/V5), which were cloud screened and aggregated by percentile 90th on Google Earth Engine-GEE. All the images were exported from GEE to R environment where the follow procedures were executed on a pixel-basis: <strong>Outlier removal</strong> based on a temporal moving window, used to identify and remove NDVI outlier values (<em>i.e.</em> greater or less than 1.5 standard deviation calculated on 60-months time window) <strong>Smoothing and gap filling</strong> approach implemented by the greenbrown package (TSGFssa method) The final product is composed by 456 NDVI global images without gaps and for each month was produced an ancillary image indicating: <strong>Disregarded pixels</strong>: -25000 (removed) and -32000 (nodata) <strong>Gapfilled pixels</strong>: -20000 <strong>Smoothed pixels</strong>: all values greater than -20000 indicate the difference between the original and smoothed AVHHR NDVI To access and visualize the maps use: OpenLandMap.org Publication in preparation. All files were internally compressed using "COMPRESS=DEFLATE" creation option in GDAL.<br> File naming convention <em>(veg_ndvi_avhrr_p90_5km_s0..0cm_</em>20000101..20000131 <em>_v1.0)</em>: veg = Vegetation theme ndvi = Normalized Difference Vegetation Index avhrr = NOAA CDR AVHRR V5 product p90 = Percentile 90th to aggregate the daily images 5km = 5 km of spatial resolution s0..0cm = land surface as vertical reference 20000101..20000131 = from 2000-01-01 to 2000-01-31 (time reference) v1.0 = version number