Validation of ILAS Version 3.10 ozone with ozonesonde measurements

Ozone (O-3) measurements made with the Improved Limb Atmospheric Spectromet er (ILAS) onboard the Advanced Earth Observing Satellite (ADEOS) were valid ated with correlative ozonesonde measurements conducted at five stations, A ndoya, Kiruna and Yakutsk in the Northern Hemisphere, and Neumayer and Syow a in the Southern Hemisphere. The ILAS Version 3.10 O-3 vertical profiles w ere compared with 79 correlative ozonesonde measurements that were made wit hin 500 km and 3 hours in distance and time differences, respectively. The comparisons indicate that ILAS O-3 typically has an accuracy within 20% bet ween 12 and 35 km. The precision of the ILAS O-3 is estimated to be +/-10-2 5% between 12 and 20 km, +/-5-7% between 20 and 30 km, and +/-5% between 30 and 40 km.