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(v) Execution of programme MIRPOINTS, which extracts digital Meteosat thermal infrared counts 
for specified point locations (some 1,200 meteorological station and other locations in Africa) 
from available hourly images and archives extracted data in a database. 
(vi) Execution of programme HRPRO, involving processing of available, in principle hourly, Meteosat 
images to determine cold cloud duration (CCD) for each pixel on the basis of satellite calibration 
data, cloudtop temperature thresholds for specific geographic regions and time intervals between 
successive images: product: daily cold cloud duration (CCD) images. 
(vii) Execution of programme DAYPRO for determination of cumulated cold cloud duration (DCCD) 
and number of rainfall days (DNRFD) for ten-day periods; stores results in ARTEMIS database. 
(viii) Execution of programme DECPRO, which converts 10 day CCD maps into\ ten-day estimated 
rainfall (DERF) maps, by using predetermined linear regression relations; stores result in 
ARTEMIS databse. 
(ix) Execution othe programme MNTPRO, once a month, which adds the three ten-day DERF and 
DNRFD maps and stores the created monthly map in the ARTEMIS databse; furthermore, this 
programme compares the estimated monthly rainfall map (MERF) with long-term normal rainfall 
reference maps and generates absolute and relative rainfall anomaly maps (MRFANABS/REL); 
stores results in the ARTEMIS database. 
The above nine processing steps are executed in a fully automated sequence, primarily during the evening and 
night hours, thus leaving the system free for other operational and developmental processing tasks during the 
day. 
NOAA AVHRR data for vegetation assessment is acquired by FAO on magnetic tape from two sources: 
(i) NOAA AVHRR Global Area Coverage (GAC) (4 km resolution) data, covering Africa, the 
Near- East and South-West Asia, as received by the satellite during daily mid-afternoon 
overpasses and transmitted to the receiving and archiving facilities of NOAA in Washington D.C. 
After quality control by NASA GSFC, data are transmitted to FAO by courier and received for 
thematic processing generally within 7-10 days after data acquisition by the satellite. 
(ii) NOAA AVHRR High Resolution Picture Transmission (HRPT) (1.1 km resolution) data, 
covering West Africa, as received by the ESA receiving station at Maspalomas, Canary Islands. 
Data are transmitted to FAO by express mail and generally received within 10-14 days after 
acquisition. 
Processing of NOAA AVHRR GAC and HRPT data is done automatically by the ARTEMIS system as 
follows: 
(i) Mapping of channel 1 (red), 2 (near infrared) and 5 (thermal infrared) data of daily available 
orbits to the ARTEMIS common geographic format projection and resampling of 4 km resolution 
input data to 7.6 km ARTEMIS product output resolution. 
(ii) Calculation of normalized difference vegetation index: ch 2 + ch 1/ch 2 - ch 1 and identification 
of cloud-covered areas, by using thermal infrared channel 5 data. 
(iii) Generation of ten-day vegetation index composites (DNDVI) by using a maximizing technique 
on all available daily data. 
(iv) Storing of the resulting DNDVI images in the ARTEMIS database.