A joint intercomparison campaign of Brewer and Dobson instruments from WMO regions, Africa and Europe, Region Association (RA -I and RA-VI) respectively as well as a training course will be held in El Arenosillo Spain. The campaign is also open to other instruments such as BiTec Sensor (BTS), with the objective of evaluating the performance and inter-relationships of different instruments and contributing significantly to long- term strategic planning for post- Brewer/ Dobson era.