MS El Rafael Prez Ruiz Research Assistant Laboratorio de Percepcin Remota y Sistemas de Informacin Geogrfica Instituto Tecnolgico de Sonora Ciudad Obregn, Sonora, Mexico MY RESEARCH HAS BEEN FOCUSED IN THE SEASONAL AND INTERANNUAL VARIATION OF GAS EXCHANGE (CARBON DIOXIDE AND WATER VAPOUR) BETWEEN THE BIOSPHERE AND THE ATMOSPHERE OF SEASONALLY DRY ECOSYSTEM IN ARID AND SEMI- ARID ZONES, MAINLY IN A TROPICAL DRY FOREST IN NORTHWESTERN MEXICO, AS WELL AS THE INFLUENCE THAT PRECIPITATION HAVE IN THE ECOSYSTEM PROCESSES THAT DETERMINATE THE DINAMIC OF GAS EXCHANGE AND THE CARBON BALANCE. EDDY CORRELATION SYSTEM: 13 m MICROMETEOROLOGICAL TOWER 3-D SONIC ANEMOMETER CSAT-3 CO2/H2O INFRARED GAS ANALYZER LI-7500 SEVERAL METEOROLOGICAL EQUIPMENT QUALITY CONTROL AND CORRECTIONS: WPL DENSITY FLUCTUATIONS CORRECTIONS EVALUATION OF THE SYSTEM PERFORMANCE WITH THE SURFACE ENERGY BALANCE (Rn G = LE + H) FILTERING USING REJECTION CRITERIA OF u* = 0.15 m s-1 GAP FILLING FLUX PARTITIONING (NEE = Reco - GPP) METHODOLOGY 3-D SONIC ANEMOMETER IRGA GAP FILLING ACCORDING TO FALGE et al (2001) AND REICHSTEIN et al (2005) FLUX PARTITIONING ACCORDING TO REICHSTEIN et al (2005) RESULTS PLEIADES (PARTICIPATORY MULTI-LEVEL EO ASSISTED TOOLS FOR IRRIGATION MANAGEMENTE AND AGRICULTURAL DECITION SUPPORT) IRD-ITSON-UNISON-COLPOS-UNIVERSIT CADI-AYYAD THANK YOU!!! MERCI BEAUCOUP!!! MUITO OBRIGADO!!! MUCHAS GRACIAS!!!