5 CONCLUSIONS AND DISCUSSION. 
During a period of eight months it was not pos 
sible to obtain imagery of reasonable quality of 
the NOAA-7 AVHRR system, a system with a near daily 
revisit capability. This is due to the high cloud 
cover, which is often present in the Lower Tana 
River region. This demonstrate the weekness of 
optical satellite systems in operational aplication 
practices and the urge for non-optical systems 
like radar for areas with a high cloud cover such 
as the tropics and many deltaic regions in the 
world. 
Despite the facts just mentioned, the AVHRR-images 
indicate their usefulness for investigation and 
monitoring of the vegetation growth in smaller 
regions. The radiometry and spatial resolution is 
sufficient to allow for such applications. Although 
no atmospheric corrections were performed on the 
imagery the enhanced images are in agreement with 
the field observations. 
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